Engine Rebuild Part 3 (the finale)
 

I'm pulling for you and have been following along since your first engine drop. Thank you for sharing. Wish I was closer so I could help. Please keep updating your build as you go. It's very much appreciated.

+996. Thank you for your generosity detailing your build for us.

It looks like you're really taking your time and doing a thorough job. I'm looking forward to the rest of the build and crossing my fingers that this is the last time you ever have to take this thing apart!

-shawn

I'm a little overwhelmed just looking at your concise pictures, and all of the work you've put into this project. Very impressed with your 'light' restoration and cleaning. Needless to say, you are fr beyond my capabilities regarding your complete engine rebuild. Bravo to you for taking on this project, can't wait to hear of your finished engine growling for the first time. Well done.

Are you a "regular" shadetree mechanic or have you done this sort of thing before? Quite impressive but probably terrifying to even consider such a project for most of us!

Can't wait to see it all bolted up and get your review on the upgraded configuration.

Wow! That is all I can say Logan. This is awesome information. I would just end up with a lot of cool tools if I attempt to do this in my garage.

Very nice indeed! Great documentation (and certainly it will help people in the future)!

Nicely done so far. Looks like you know what you're doing and being very detailed with respect to clearances, which is key.

What did you end up with for imbalance on the pistons/rods?

A great service to the m96 community. Thanks!

btw, I thought I read all 6 compression numbers where fairly uniform, so I don't get how #2 clogged jet could do all that?

simply WOW

Logray thanks so much for documenting your rebuild. 3 months is a long time and the anticipation mustve be difficult. As you know Im currently waiting for my 3.8 nickies to return to me for my rebuild. I think most of us here can handle small jobs such as brakes and suspension but to rebuild the motor in your own garage is quite impressive. I wish I had the knowledge and experience to do it. Im looking forward to the day you start her up. Good luck with the rest of your assembly. Please post impressions once you've taken her out for a test drive.

Thanks all, can't wait to get the car running again. Really miss driving a real car instead my F150 boat.

As for imbalance, the engine balancer said he got it "dead on", with a wry grin of course... within .2 grams for a set of 4 is what I was told.

The DMF was about 20 grams off at 5 inches out mind you... took quite a bit of trimming to get it in balance. They had everything bolted up and balanced on the balancer... then as soon as the DMF was bolted up it threw the whole thing out of whack.

https://lh5.googleusercontent.com/-E...0/IMG_4644.JPG

The pressure plate didn't need as much trimming.

https://lh5.googleusercontent.com/-d...0/IMG_4645.JPG

And everything is indexed and ready to bolt back up once I get to that point... which will be a ways away.

It's only a theory at this point that #2 jet was clogged just enough to not allow as much cooling oil to #2, thereby heating it and adjacent #1 and #3 ever so slightly, and very slowly over time. Perhaps it was allowing enough flow and this is just normal wear and tear. The rings seemed overheated and brittle, especially when comparing them with the new rings. While I was removing one of the oil control rings in bank 1 it cracked in two with very little effort on the ring expander.

The oil foiling was in bank 1 where the trashed piston jet was... no fouling on the other bank. And I have been told not to expect conventional symptoms from this engine... so the even compression may have been a red herring. The leak down test did show slightly higher numbers in bank 1, with everything leaking past the rings... vacuum gauge showed below normal readings and also pointed towards worn rings.

Those were the only issues I could find. It's sorta a moot point though with a total overhaul. New cylinders, rings, pistons, and on and on and on as my wallet is burning.

You're an inspiration to us all. Keep up the good work and the pictures when you can.

I'm also looking forward to your impressions to your new engine.

an oil control ring failing (brittle) would explain excessive oil getting into combustion.

I bet that thing is going to rip once it's all back together! Since it's balanced so well and has the JE slugs now, do you plan to raise the redline a few hundred RPMs?

Thank you for posting this. Great photos.

sweet! great update!

Agreed, a great thread with lots of fantastic pics and information. :thumbup:

Great rebuild pics! An awesome contribution to the 996 community. Thnx!

within .2 grams is great and far better than factory (i think in the 993s they permitted up to 6 grams of mismatch).

Trying to balance with a DMF has got to be murder. No thoughts of ditching it for a lightweight flywheel?

Can you please identify the thrust shims in your pics. I remember someone here had an issue with his crank a few months back....

jrgordonsenior: Thrustshims are in the middle of the bearing carrier.

https://lh3.googleusercontent.com/-K...2/IMG_4647.JPG

Borrowed your pic logray :)

And thanks for superb thread :D

I've thought about a LWFW, but everything I've read says to stick with the DMF... and this is not a race car. As you point out though, it is a little tempting with a well balanced engine. I'm after longevity first, and performance second.

Yep, you can see the thrust shims in that pic pointed out above, a little horseshoe looking piece on the 4th tower from the bottom (or top) of pic. There is one on the backside too.

It's important that they are installed with the grooves facing out, and axial play is measured during and after carrier assembly.

From what Jake tells us, sometimes this material is soft from the factory (perhaps leading to premature failure as mentioned earlier), and I believe he has a process to cryogenically enhance them. I'm not sure if he also coats them with PC3 anti-friction for further longevity.

hmm, those wrist pin clips don't look like they have much area to keep the wrist pin in place.

perhaps thats just the picture.

Hmm, I'm sure it's fine, but I see what you mean.

There is a chamfer on end of the piston pin, so if pin moves the chamfer pushes the pinclip tighter to the groove.

Great catch! You might be onto something here actually. It looks like I accidentally inserted the clips backwards. The hole for the tang in the piston is drilled at an angle, and the tang on the clip looks like it should go at the same angle. DOH! Well good thing I haven't dropped the bearing carrier in yet (or worse, sealed up the case).

They are certainly seated though, but I will pull those clips again and order up some new ones.

edit: Darn, 1 week backorder on those clips. Another week of delays. :(

Here is a pic of an unsuccessful insertion courtesy flat 6 innovations website, you can see the the clip is not seated in the inside groove (but the correct orientation of the clip):

http://flat6innovations.com/images/s...ssembly/45.JPG

Good work and nice write up!

I'd mention the greatest area for a potential problem is in the wrist pin clips. After installing them all, measure the ID of the installed clip with a dial caliper. If any are smaller, that means it's not seated fully in the groove and may back out. This could be due to a wrist pin being a bit too long, insufficient depth of ring groove or just the clip not being fully seated.

Also from your earlier specs, bore of 3.8976 and piston size of 3.8945, this yields a clearance of .0031, your specified clearance is .0035. You're on the tight side of the spec. and I realize it's +- .0005. Being a bit tight is OK but break in will be more critical and you could develop a bit more heat in the process. For this reason I'd give a couple of more thou to your ring gaps. This will be a safety valve and eliminate a potential ring butt failure. The recommended gaps are generally the absolute minimum and I like to give a bit more, say .002-.004+ for both the top and 2nd. This is good insurance and gives you a cushion. I've seen many motors with collapsed pistons and scored cylinder bores just because a ring butted. A couple of extra thousanths of added ring gap would have prevented this.

Another couple of points, check the sharp edges of the machined piston pocket edges on the crown. If these are sharp, radius the edge very slightly with a stone or crocus cloth. The sharp edges can cause detonation from glowing heat.

I also started assembling pistons and rings dry about 35 years ago. Assembly lube on the pin and a spot on the thrust faces of the pistons, dry clean bores, dry rings and grooves. Many long time builders do this, many still oil everything up fully.

In building motors, more info is better. Make your decisions based on hearing opinions from those in the trade that build successful motors. Decide what is right for you. Not trying to tell you what you should or shouldn't do, just passing on a bit more info to chew on.

GL!

Thanks for the tip!

This has been on the back my mind too. I am going off what LNE is instructing since they finished the cylinders and provided the piston specs to JE.

edit: the piston/wall clearance is to be set to .0035".

I'm still chewing on the numbers myself, but here is some more info to throw out.

There is a coating on the piston skirt where the measurement is taken which might add .0005 according to LNE.

The bore spec is 99mm, which is actually .0000378 larger than 3.8976.

JE recommends minimum end gap clearance of appx .0043-.0045 per bore inch for this product. Which works out to something slightly different than what LNE recommends.

Top .017"
2nd .018"
Oil .015"

I inquired whether to use those numbers since it was somewhat unclear based on some other instructions and was ultimately provided .015 top, .016 middle, and .015-.016 for oil. The oil rings were already within that range.

This isn't something I want to screw up, and I do appreciate the advice. It's easy to remove material but adding material back means ordering a whole new set of rings. :(

I gave them a once over after the machine shop checked/recommended the same thing. There was one piston that needed a little deburring. The rest are smooth as butta.

Interesting. I wonder if that is based on the application you were using (CI?), and Nikasil warrants oiling it up. Everything I've read for this specific product says to lube it up to promote ring seat/seal. These are recommendations from both LNE and JE.

JE:
"We recommend a light coat of non-detergent oil on the piston's skirt and cylinder walls for initial installation. DO NOT USE DETERGENT OIL, SYNTHETIC OIL, OR AN ADDITIVE until the rings have seated."

LNE:
"We recommend a light coat of non-synthetic oil motor on the cylinder walls for initial installation ... Do not install the rings and cylinders dry!"

Porsche factory manual recommends the same thing.

I attended the M96 101 Engine Building school at Flat 6 in Sept. Jake recommended grinding off the hook on the wrist pin clip flush with the clip. The potential for not lining up the hook with the hole is too great and if the wrist pin clip falls into the carrier during installation, the carrier will often need to be disassembled to find it. All the wrist pin clips we installed had the hook ground off.

For 99 mm bored engines Jake recommended 0.015 for the top, 0.016 for the second and 0.015-0.016 on the oil ring.

Wow thanks. That really restores my confidence on the gaps.

So you mean to say you ground the hooks on the clips completely off, so they are in a sense round, with no tang?

Yes, the hooks were ground off flush so that the clip is a perfect circle. That way, the hook can't get hung up and pop off if it isn't aligned perfectly. Lining up that hook would be tough.

Here's a picture from the course that shows a clip that has had the hook ground off. (sitting between the 2 wrist pins)

Wow! What a marvelous idea! This will make the 4-6 insertion much less painful. :) I think I will still keep the hooks on for the other 9 clips I can see easily and do on the bench.

Thanks for sharing (and of course thanks to the brains behind it if you are lurking.)

Next week I'll order a new set of clips for the 1-3 pistons I'll be re-doing. Since I shouldn't be re-using clips that have already been installed.

Quadcammer I owe you one for bringing this subject up!

Another tip:

warming the piston with a heat gun/hair dryer will make it so you can drop the pins in place and push them through with a finger. If the pins are a light press or interference fit in the rods, warm them too. This will preclude the use of the driver and hammer. If after warming they are still a bit tight, chill the pins in the freezer for a few minutes.

Use a straight seal pick as a lever tool to install the clips. You'll get to where you can snap them in place in a second or two, first time every time effortlessly. I'd still verify the clips are fully seated by measuring the ID.

I'd also keep the hooks on the easy clips. Its the last 3 that I would grind off.

Thanks again! I certainly will carry out those measurements (except for 3 of the clips that are done blindly a foot deep in the case where that would be nearly impossible).

The fit on the wrist pins is very tight, like .0005 to .001. The machining tolerances are impressive to say the least! A careful hand is all that is necessary.

As for installing the clips, I'm still not sure what the "best" method is. I've read that some can do it with brute finger strength, others with strange angles and twisting, and others still the use of tools. I'm pretty sure tools are the answer and I wouldn't disagree that a pick would be a good tool here. If you've seen the tool that inserts the clips over a foot deep into the 4-6 pistons after they are installed in the case, it might become more clear. So far, this appears to be the best method... the clips are not twisted, yet compressed in a similar fashion that is required to place them into the insertion tool (if that makes sense). If the tool is good for installing 3 of the clips, then it should be good for the rest.

https://lh6.googleusercontent.com/-1...0/IMG_4662.JPG
https://lh4.googleusercontent.com/-Q...2/IMG_4663.JPG

Installing wrist pin clips was my least favorite part of engine assembly. Those things are finnicky and a real pain on the finger.

With respect to ring gaps, I always tended to aim for the looser end of spec. With high oil temps and extended tracking, I like the additional gap, even with slightly higher oil consumption. A butted ring does some really ugly stuff.

If you leave the hooks on the other 9, is the difference between cut and uncut weight going to throw off your balance? Or is it to small an amount?

Just guessing but the clips are probably worth a couple grams, and the hook might be worth 5-10% of that. I could do the same on the other bank to even it out.

Anyways, I'm contemplating keeping the hooks in place, since it's my car and my time if I have to crack the case open to fish for clips it's not the end of the world.

Update:

Two steps backwards and one step forward.

I received 4 of the replacement 6 clips that I need, there was a slight mix up when I said I need three packs of 2 (and they charged me for three clips and sent 4 rings or two packs of 2). The other 2 clips are to arrive Tuesday, along with... tada!

http://www.flat6innovations.com/rrproboxsterrods.JPG (image courtesy F6I)

I was at a point in the rebuild where I had to make the decision which had been on the back of my mind since the get go. Yes I already dropped some pistons into the cylinders, but call it an anxious test fitting or what have you (I'm over it and thanks again) ;). I blew the budget and ordered a set of R&R rods from Charles to arrive next Tuesday. I couldn't bear buttoning this thing up and driving her around for 10 or 15 years with brand new everything pretty much but my same old tired rods.

During the idle time waiting for the clips and rods I also had a chance to mull over another potential issue while re-measuring everything for the 15th time. This issue did not come up during the initial test rig fitting.

On the other case half that I had not yet assembled, I test fitted all of the rings again. What I discovered was that the oil rings seem to be a few .001" too small. When I say "seem", it is REALLY difficult to get a precise measurement with a .015" feeler gauge. The gauge "fits", but not apparently without slightly distorting or moving the oil rings out of alignment. It is very very difficult to say this with certainty and a straight face though, as there is a small amount of oil in place while taking the measurement to help keep the oil rings from moving, perhaps that oil is throwing things off. The oil rings are extremely thin, and don't have much spring to them, so just resting in the cylinders there is a small amount of clearance between them and the walls. I can square them up fine, but as soon as I attempt to get a feeler gauge in the gap the rings move ever so slightly. The only ones I can fit in without them moving are the .013 and .014 gauges, but even then it takes more than a steady hand and my measurements are sometimes skewed if I barely touch one of the rings with the gauge.

Here's where it seems to get a little weirder. I tore down and cleaned the other cylinder half and re-measured those as well. Same thing! Every single oil ring in every single cylinder has the same problem. They all appear to be about .001 or .002 smaller than the recommended .015".

Now I'm not adverse to filing every single oil ring (as I have already done with the top and second rings), which will be difficult since they are so thin, even with a dab of oil the piston filer might chip the face so I might have to remove the .001 or .002 "by hand" with a wet stone or jewelry file. But it does strike me as odd that not even a single oil ring is correct. Perhaps JE messed up the machining or sent the wrong rings or LNE didn't finish the cylinders at 99mm???

I did measure the cylinders at .0001" smaller (3.8975") than LNE did (3.8976") during their quality check, and 99mm is .0000378" larger than 3.8976". End gap measurement does change by a factor of Pi, so perhaps the math does work out if my measurements are right.

If the oil rings were made to fit a 99mm bore based on a .015 gap, and the cylinders actually measure out to be .0001378" smaller than 99mm, that works out to .0004" less end gap. Which might explain why the .014 fits but the .015 does not appear to.

Even though I'm working at 68F (JE recommendation), I'm wondering if perhaps that is not right either, and it's supposed to be 72F as I read elsewhere and may account for a few .0000x" skew of the measurement as well.

All of the cylinders are extremely close though. I can pretty much interchange any of the rings I custom filed to the other cylinders and they are almost dead on (with the exception of a couple that are slightly larger).

Now obviously I don't want rings ends to butt, and I am guessing everyone will suggest to file them down and wider is better... however does anyone find it odd that not a single oil ring appears to be correct from the factory?

Comments and suggestions are much appreciated !!!!!!

With the slight temperature differences and typical measuremt errors that can occur when dealing with units this small, I would feel safe to just run the oil rings the way they are (unless you plan on starting up the car in the artic circle). We often run ring clearances much tighter than the published specs without issues, so don't loose any sleep over the oil controls being .001" small.

I'd actually be more concerned with where your compression rings are now. As stated before, I'd open up the top maybe .002" .003" more for good measure, and have the second at least 2-3 thou larger than the first. This additional amount will not cause any compression loss at all, just a huge safety valve if one cylinder or more happened to run a bit hot for any one of many reasons which they can. These include a partially clogged injector, slight blockage in water passage, blockage in oil cooling jet , air leak in intake and several others.

Very slightly tight oil rings are not nearly as serious as tight compression ones, that's because that portion of the the piston is much cooler than the crown that is in contact with the hot combustion gasses. Where the danger lies is if a compression ring gets a bit tight, friction dramatically increases, which in itself causes much more localized heat that makes the piston swell to the point of seizure. This ruins the piston and often the cylinder surface as well at the very least.

This is not a go kart motor that you can fix for $50 and 2 hours if something goes awry. I can see you're full of questions and certain amounts of uncertainty. Make it easy on yourself and clear all the doubt. Doing this stuff for a living since the '70s, I know that every motor will start instantly, sound terrific, and no noise or smoke before I attempt to start it for the first time. It's knowing about potential problem areas and addressing them and removing all doubt during the building process.

Drag the oil scraper rails on a stone a couple of times till you can push the .015" blade in there and if you're so inclined open up the compression ring too. I would, you'll sleep better.

Don't run anything more than the .015" on the top and .016" on the second with this normally aspirated build. This is tried and true with 300+ engines built to these specs.

Listen to these guys first and foremost! They are the experts on these motors. Advice I was giving was general and not Porsche 996 specific.

Thanks for the input, I really appreciate it and it is a major confidence booster. No, the car will not start in the arctic circle and probably won't see too many below freezing start-ups.

I think at this point that the differences in measurement could be attributable to temperature or just very slight differences in machining. Similar to the way the temperature of your hand affects the width of the .001 feeler gauge perhaps.

After spending more time with it, I can say for near 100% certainty that at 68 or 72 degrees, the .014 gauge is the only one that fits without distorting the oil rings. The .013 gauge slides in with little resistance, so I'm pretty comfortable knowing the gap is greater than .013, but less than .015. The .015 gauge will only fit if it distorts the rings. Here are a few pictures of the .014 gauge in an oil ring gap.

Mind you, the .014 is a tight squeeze in itself, holding the feeler gauge on it's own.

https://lh6.googleusercontent.com/-w...0/IMG_4672.JPG
https://lh3.googleusercontent.com/-_...0/IMG_4673.JPG

And thank you Nick for the comments. I think under normal circumstances I would open up those gaps a little wider, but seeing as how these are the recommendations from two very reputable sources for this particular engine and material, I am set on running .015, .016, and .014 at this point.

Excellent writeup. It's good to see some of the rebuilds in greater detail.

Although one RL'er insinuated that everyone who owns a 996 needs to know how to do this, I'll just tip my hat here and leave it to the experts. Way beyond my comfort zone.

Thanks!

I've been doing a little research on the use of sleeve retainer Loctite 640 and use on piston spray jets.

Over in the 993 forum here and on pelican, apparently when installing the squirters, some use a tiny dab of sleeve retainer for the jets.

When installing my jets, they really didn't need to be "pressed" into place, in fact they pretty much dropped right in without much interference. Conversely, when I removed them they didn't put up much of a fight, in fact, I sneezed on them with an Allen wrench and they dropped right out.

I'm wondering if I need to be concerned about them floating around, or if the oil pressure from the oil galleries, pump, heat expansion, and spinning crankshaft will be sufficient to hold them in place.

I did clean the new squirters before I installed them place.

I use the 640, Jake Raby says he often finds the squirters loose during disassembly.

Thanks for that bypro!

Back to work today with a few updates.

Clips arrived and installed successfully and CORRECTLY this time. Everything cleaned again as if though I were sending this car into outer-space. Reminds me of the few times I've visited a data recovery clean room. Pistons re-installed into the 1-3 half. Here are a few clip installation pics.

https://lh6.googleusercontent.com/-A...0/IMG_4678.JPG
https://lh4.googleusercontent.com/-L...0/IMG_4679.JPG

New R&R rods arrived and bolted onto the crank. Man-o-man are they pretty. Now I can sleep at night. The machining is impressive to say the least. I emailed Mike to be sure the small rod bushes were right, the tolerances are pretty crazy tight (considerably tighter than what's in his instructions)! A great thing is that they come already balanced within a gram, magnafluxed, precision honed, measured, ARP hardware, etc. A worry free experience to say the least.

https://lh4.googleusercontent.com/-P...0/IMG_4680.JPG

And looked through the WSM and found this interesting picture. It seems to be the only mention that the hooks need to be ground down before using the tool for the 4-6 piston installation. Funny how it's not spelled out except for a little dashed line around the insertion tool. Well I'm sure if it wasn't mentioned here I would have encountered that big oops while trying to put those clips into the 4-6 pistons. Good thing it would have been my time... but if this were someone else's engine I would be working on that would be a big loss. Sooooooo much time would be wasted !!!!!

https://lh5.googleusercontent.com/-z.../s307/clip.PNG

Hopefully tomorrow the short block will be ready for the heads... still have to complete and drop in the bearing carrier and seal the 4-6 case half before the only part of this build I've been dreading... the 4-6 clip installations.

I didn't ground the hooks, if you insert the clips in the tool with an angle the hook will fit thru the holes in the block.
And that's the only reason, that I can think of, why the hooks should be grind down. :)

Nice to see that your project is going forward, can't wait the dyno numbers ;)

Just got my 3.6 w/3.4 heads & cams back yesterday. I too will be excited to see my dyno numbers and yours once you get it completed. Mine's all stock w/slightly decked heads. My 3.4 dyno'd around 270 on a Dynojet, this one shouldn't be much more, maybe 280. It certainly idles and revs up nicely. I drove it easily around the block and will break it in next weekend weather permitting....

Thanks speed, yeah I do plan to grind the hooks for the 4-6 installations, I'm not sure if completely off or not. But it does make perfect sense if they are perfectly round there is less danger of them flying off during installation. If I were doing this for a customer I would probably do that. The hooks supplied by JE are a little bit longer than the stock hooks, they probably would have a problem fitting through the hole.

Yes, certainly will get it on a dyno, but a lot of work before then!

Some progress today, but a possible issue with deck height. The pistons are out of the hole by a tiny bit, and I haven't had time to measure how much yet. I see the specs on LNE's support site are .04" to .06". Not sure if that applies to M96 or air cooled. I don't think that is for M96. Not sure if this will be a problem if the pistons peek out of the cylinders at TDC. If I press down on the piston tops and try to square them once they are at TDC, I can get negative readings in the hole by appx -.003" to -.005". But just the action of the crank turning puts them ever so slightly off square and out of the hole. And certainly normally there is some oil in between the bearings, affecting this reading as well. Any guidance here would be appreciated.

Here's today's action.

Completing the bearing carrier with chain guide, billet tensioner & pad, and some chains.

https://lh3.googleusercontent.com/-F...2/IMG_4682.JPG

New washer and clip installed for the LNE billet paddle.

https://lh6.googleusercontent.com/-P...0/IMG_4683.JPG

And some chains. Ohh.... these chains are going to be a pain in the butt during install.

https://lh4.googleusercontent.com/--...2/IMG_4685.JPG

Pistons in and pushed to the top of the bores ready to drop in the bearing carrier.

https://lh5.googleusercontent.com/-D...0/IMG_4686.JPG

Bearing carrier dropped in.

https://lh5.googleusercontent.com/-7...0/IMG_4687.JPG
https://lh6.googleusercontent.com/-6...0/IMG_4688.JPG

Pistons pushed up to the crank and rod caps installed and torqued to spec.

https://lh5.googleusercontent.com/-G...0/IMG_4690.JPG
https://lh4.googleusercontent.com/-0...0/IMG_4691.JPG

And this was as far as I got. Measured the deck height on the pistons at 3 and 9 o clock, the flat top portions of the piston. I haven't yet had a chance to measure how far out of the bore they are at TDC. As stated above after gently "pressing down" on the pistons to where they were as square as I could get them I measured between -.003" and -.005" (piston top below deck).

https://lh3.googleusercontent.com/-W...0/IMG_4692.JPG
https://lh3.googleusercontent.com/-z...2/IMG_4693.JPG

Re-calibrated instruments, and took a fresh set of measurements, a couple times each cylinder, not touching the piston after it reaches TDC.

+ indicates piston top above deck, - indicates below deck. Top = top of engine measured on flat topped piston face.

Cyl 1

Top -.005"
3 & 9 o'clock 0"???
Bottom +.005"

Cyl 2

Top -.0028"
FW -.0020" (9 o'clock)
Pulley -.0010" (3 o'clock)
Bottom -.0008"

Cyl 3

Top -.0036"
3 & 9 o'clock 0"???
Bottom +.0050"

engine porn....love it

Well crap. I think I may have hit a wall here.

Can't find any info about proper deck height, looking at the figures, and guessing it's supposed to be 0 decked, and then within some tolerance of that. What that tolerance is + or - is no where to be found.

The only thing I can find which seems to be pertinent is the engine build page on F6I's site stating when Jake measures the deck height, all were within .0015" of each other. Judging by the pics and the instrument used the pistons appear to be in the cylinders during measurement.

That's about right on the deck height - nothing to worry about there. You rock the piston one way, measure, rock it the other way, measure, then take the average of the two.

You're forgetting the head gasket thickness, and that accounts for most of the total deck. FYI, these engines run a VERY tight deck, we've seen some tighter than .024" including the thickness of the head gasket, but it varies from block to block.

That's why it's so critical to lock cams when doing an IMS retrofit - if the timing jumps even the slightest, you get piston to valve interference. That is also why when the IMS bearing fails, even the slight jump in timing is catastrophic. This engine is very much an interference engine. We do however build in more valve pocket than is necessary in the pistons, just to add a bit more margin of safety.

This is good information, I do appreciate it!

Yes I was forgetting the head gasket. The hand smacking the forehead moment became apparent to me when I pulled up a compression ratio calculator, measured old head gasket, and played around with some numbers... the chamber CC figures I used were just a guess. It seemed like a few .00x's in either direction didn't affect the ratio that drastically, .022 deck produced 11.9:1 and .025 deck produced 11.7:1... and I suppose the point being the heights should be very close otherwise there is a problem to solve.

Interesting the valve pockets on the new flat topped design appear to be symmetrical, different from earlier designs. The pocket casting recess on the underside of the piston does look different on the exhuast (JE logo side) from the intake. But according to the build sheet, intake and exhaust pocket depths are both .213" and 15 degrees! ;)

Figures I used:

HG width of .022 ish
Pistons .003 to .005 below cylinders
Appx .025 total deck
Chamber CC: 51 (don't have actual spec or measuring kit)
Displacement: 3603 CC / 220 CI / 3.6L !!!! :)
CR = 11.7:1

Produces close to the advertised* CR of 11.8:1.

I'm going to double check my preliminary measurements that I took after rocking the pistons, but looks like I'm back on track today to seal up the case and drop in the other three pistons. :)

*advertised CR: there is a disclaimer on LNE's site:

"specified compression ratio may or may not be an exact representation of the actual compression ratio and may vary slightly from the advertised compression ratio"

:):):):):):):):):):):):):)

Preparing to mate the case halves. Cleaning everything is ongoing. In the case of the cylinders it is critical. They have already been scrubbed, cleaned with hot water & dish soap, cleaned some more, more compressed air, more cleaning. For the final cleaning, I take some accuwipes (like them better than kim wipes b/c they are thicker), and denatured alcohol and rub the cylinders until there is absolutely no residue on the wipes when they come out (left wipe residue, right wipe no residue).

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The inspection proceeds with a final up close inspection with a flashlight, up close in all of the oil galleries, water passageways, looking for any casting flash or any debris that might cause a problem. The mating surfaces of the case halves are cleaned again with acetone, and the mating surfaces of the bearing carrier and case halves are cleaned. Even though the threads were cleaned prior to shipping to LNE, I chase them again. The water channel gaskets are placed into the 1-3 halves.

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Preparing to apply the drei bond. I had to raise the temp to about 65 in order to apply this, it says over 59 degrees. I measured out appx 1.32mm bead.

https://lh4.googleusercontent.com/-c...0/IMG_4705.JPG

Before applying any silicone, make sure you are 100% ready to drop the case half on. You need a helper. The pins and sleeves need to be in place. You need to have the new bolts ready to insert. Study where to apply the bead of silicone and have the diagram right next to you during application. There is very little time to work with once you start dispensing the silicone. I put accuwipes between the rods to hold them in a vertical position so they don't get in the way during lowering of the half. The 4-6 chain is carefully folded onto itself so it rests out of the way and can be picked out of the chain box later.

https://lh5.googleusercontent.com/-M...0/IMG_4700.JPG

And the next part is magic. There's no time to take pictures. The silicone goes on, and carefully lifting and setting the case half in place set into the align pins and sleeves. Then bolts go on, torqued per the WSM and in a specific sequence. Then a sigh of relief.

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Inspecting the oil scraper gaskets from the sump to make sure they are correctly seated after mating the halves.

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Tomorrow, the REAL fun begins!

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Logray. I am really enjoying following this. Great write up!

Thanks Doug!

Ditto.

BTW...I'm sending you my engine ;)

I hope you are taking a count on how many hours you spend on this work... that will be an interesting number :D

I might send you my engine too :D

Awesome write up, I've really enjoyed reading it. Thank you for all the details and pictures.

:cheers: looking good logray :)

holy bloody christ that is so overly complicated its insane. how are you supposed to get the rod to stay in place while you put the wrist pin in?

aye

Logray

Thanks again for all the work you are doing documenting this. I realize how much extra time is required to take all the photos and to write everything up. Back in 2009 when I was undertaking the fix of my intermix I started with the intent to photograph and document every step. But that intent soon fell by the wayside as it could easily double the time involved.

I have always thought that Flat 6 should produce a DVD/Video on the rebuilding these engines to compliment the classes they offer. Maybe you should beat them to the punch. I for one would gladly pay to have this sort of documentation if I was undertaking a rebuild.

You don't even know the half of it. Insanity is a good term for it. I lost a lot of swear words in the process. It certainly twisted my brain around a few notches to come up with some of this stuff, since it's not all in the work shop manual.

The rod stays in place by gravity, and a little lube. No joke. You flip the case upside down, and since the piston is at bottom dead center the rod is at a neutral point on the crankshaft centered in the cylinder. As long at the other side of the crank case is level the rod won't swing out of direction. There is an alignment tool you are supposed to feed through the piston into the rod, but I found the tools that I purchased were pretty low quality, and the alignment tool was bent, so it would always nudge the rod out of position as I was twisting it out, despite being lubed up. Let me tell you how fun it is to remove a pin that doesn't want to go in from only that hole in the adjacent cylinder. Good thing it only happened once. In the end I was able to get perfect alignment using the boroscope on a TV and a mirror (it is a very tight fit IIRC =< .001" for the pin in the rod and piston). A cold pin in a warm piston and rod helps too. ;) #6 is a huge pain in the ass, then it gets easier from there.

Doug, I considered "selling" this info, but... the market for DIY M96 engine rebuilds are very small, probably not enough to justify the time put into it (and then I would have to support it/etc.). A shop like flat 6 has a much better chance at doing this based on their experience. But it's interesting their DVD has been "in progress" for so long but perhaps never finished... possibly due to the same reasons? I think Jake's onto other things and would rather teach the classes, which I hope to attend some day. Also a pro shop would be unlikely to buy something from a shadetree DIY'er. So I figured I would post it here for the community. I will archive it off though in case something happens to RL. It's not all here anyways, this is a summary, I could certainly go more detailed but don't have 4x time...

That being said, there isn't much here that hasn't been said before (or posted before, or provided in pictures elsewhere)... and the process basically mirrors the work shop manual. Have you been up to flat 6's site, his engine build web page? It's not drastically different from this thread. Mind you there are some places where you have to get creative, no shop manual or DVD is going to help you.

No guts ... no glory... wonderful wright up and have enjoyed the tread may the rest go smooth for you and first start not be to nerve racking.

I agree 1000 times.

Thank you logray!!!

wow...bet you long for a nice simple V8.

Keep up the good work.

More thanks. Following you on this is has been fascinating!!

When it comes to removing the old sealant from that pan, I'd suggest trying a scotchbrite sponge (blue). I tried a variety of methods and this was the best by far. It took the sealant right off without damaging the light texture on that face. The red/brown scotch brite pads were too aggressive for my taste.

-Shawn

Thanks for the tip! I think I might try that out. I like the red/brown ones myself.

Hey Logray,

Superb thread, i love it and hope many will tempt the journey of rebuild like you thanks to your posts.

Keep it coming, I love this thread !

Agreed, the red/brown pads are awesome for heavy cleaning. I was just worried that I was removing the texture on the seal surface so I went with a lighter option.

You're in the home stretch so I'm sure the excitement is building... Good job!

To clean sealant do you use any product ? Or just scotchbrite dry ?

Acetone or paint thinner work great along with the scotch brite.

Who/what baffle system is that? Much different looking than the X51 baffles....

Stock 996, I might open up the baffles a little, perhaps when some funds come in along with a deeper sump kit.

I'm having trouble remembering. I think I just used IPA, but I might have used simple green first and then followed it up with IPA. I definitely finished with IPA to make sure I had no oily residue or contaminants on the surface.

what is IPA ?

Not a beer drinker huh? :roflmao:

Isopropyl alcohol.

Sorry, I'm used to working with science people and we always abbreviate it.

You've got a PM.....

Thanks JR.

That new tensioner looks familiar! I also bought a set of those tools for future use, kind of a just in case. Sorry to hear they are not quite perfect. But it looks like the timing tool works well.

Did you know that the head gaskets in the 3.6 and later in the 3.8 were changed from the earlier 3.4 in the way the cooling passages were made. In the earlier versions the opening in the the gaskets for the cooling passages were of different sizes to vary the flow to different areas of the engine to better control the heat. When Porsche went to the 3.6 they made them all the same size. I read somewhere that this has contributed to hot spots and may be some scoring of cylinder heads. I forget where I read this, but if you look at the 3.4 gaskets there is a left Iand right version due to the sizing of the holes and in the 3.6/3.8 the left and right are the same as the holes for the cooling passages are all the same size,

Glad to see you are back online for the project.

Yes, I've read about this and have the old and new gaskets to compare (want to see a picture?). And understandably, this might be a problem with stock Lokasil, pistons, and stock thermostat (and perhaps without other mods depending on how you drive the car).

I asked about this, and was told that Nikasil along with the JE pistons and 160 degree thermostat is all that is needed to tackle this problem for "street use", and no other mods necessary for the larger head gasket (although the chain box bolt hole was a small surprise but no big deal). If this was a race car on the other hand... keeping the oil cool might need the help of a deeper sump, accusump, dual tandem scavenge pumps, and an externally plumbed oil cooler to replace the stock oil heater.

And yes, I'm sure the new actuator will work out fine, even though it is old stock. I ohmed out the solenoid and it is fine. There was a nice coating of oil on the actuator while in storage so I'm sure it's OK. Thanks again! :)

Bravo for all the picture and your work documenting this ! this is great.
I wish I had more miles on my car to justify the giant 996 puzzle game :)

:corn:

Short update. A few final things completed before raising the engine and mounting it. All electrical, water, hydraulic, and fuel connections completed.

Adding fluids, priming engine with oil, installing spark plugs and coils, mufflers, and perhaps first firing tomorrow.


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Bravo!

Hey Carey, thanks... at least one person is still reading this thread. ;)

When do you get your car back?

Log what kind of oil are you putting in it? :icon107: Just kidding...

Have fun breaking it in. Nice and very informative with pictures documentation of the procedures to go through.

Oh, we are all reading this tread and give you the thumbs up. Awesome write-up!!!!

awesome! waiting for the video of first firing.

I check your thread for updates twice a day! Can't wait for you to fire it up and enjoy the fruits of your labor. Your thread has been terrific and will be used as a reference by many who follow in your footsteps. Thanks for taking the time and making the effort to share with us!

logray, Thanks for all your added effort by bringing us this highly informative thread. I have looked forward to reading all of your updates. The photos are great.

Haven't missed a single word :thumbup:

Getting close my friend... Received all my LN parts except the cylinders. I was told they will ship this week. Im like you, been driving my pickup for over 3 months now. Its time to get back on track... :cheers: so, when's Your start up ceremony???

I love what you are doing Logan. The waiting period during break in miles are going to be tougher than the build..

Bravo! Fantastic! Congratulations!

Congratulations Logan. It must be a great feeling! Especially to not have any leaks, etc. now for the first drive!

i got so excited when I saw this I sat down to show it to my wife. Then when I started to explain why I was so excited I realized you "just had to be there":)

Congrats man I would never be able to do this but it has been fun to read.

Really sounded smooth. Nice job congrats.

Bravo-there are two sucess stories here .The obvious one that the engine is done .The other is the fantastic documentation along the way .The pictures and narrative are excellent and useful for all of us.
Thank you .What's your next project ?
Dave

:rockon:

Now go drive the S***t out of it :burnout:

Thank you for taking so much time documenting all the process !

I think this is the best engine rebuild thread so far. You almost have enough to make it a real book.

I wish Jack would have his DVD out, so that I could watch the whole thing on my HDTV during the cold winter nights :)

Congrats, and great thread. Very informative and a great read

Fantastic!! What a thrill and reward that must have been for you after all that work. I'm excited just watching it and thanks again for all the extra time spent documenting it for all of us to follow!

Thanks everyone. Yes, you certainly had to "be there".

It was an anxious but gratifying 15 minutes after startup, scrambling around looking for leaks, listening for strange noises, monitoring the computer and vitals... even after a good nights sleep, I'm still amazed that there were absolutely 0 issues. No leaks, no unusual noises, no hard starting, no hesitations, etc. It started almost immediately as you can see from the video, and aside from the puffs of smoke/oil burn off from the tail pipes you would have never known it missed a beat in the 4 months of downtime. Pulling the plugs and injectors, priming the oil and fuel prior to starting probably helped dramatically with the easy startup.

Without having been in the drivers seat yet, my first impressions were that the engine seemed to run incredibly smooth. With my hand on various parts of the engine, there were no hesitations or wobbles. The person monitoring the gauges and changing the rpm's commented that he could barley feel the engine.

The sound was incredible. The 3.6L stock cans along with the fabspeed headers give it a nice throaty sound. The video and audio recording from my cheap camera simply do not do the sound justice. It was pretty incredible to hear it roar, especially up to the 4000 rpm area (can't wait to go higher!). I will post some more video later once I have time to edit it down and publish HD quality stuff.

While monitoring the vitals, I almost had a heart attack, I saw 14 degrees cam deviation on bank 2, but then remembered I was using the wrong file provided by Durametric (with the current version 6 you cannot monitor bank 2 cam deviation on ME5.2.2, but I helped them debug this so it will be included in the next release of v6, if not already available). Once I got the right file loaded up both banks were at 0 degrees and steady, but I think it might have ticked over to 2 degrees by the time the 15 minute run was over with (I've noticed ME5.2.2 DME after battery reset is slow to register cam deviation, it might take certain conditions before it completely registers). I'm fine with a 2 degree cam timing advance on both banks.

Monitoring other vitals, after the 15 minute run everything looked normal, by the end of the run, IATS was 63c, ECTS 102.8c, and oil temp 111.8c. Not surprised it heated up a little in the garage with just the one external fan blowing on the front and the two high speed radiator fans turned on manually. Didn't have a time to look at rough running or other values yet, but a brief glance at O2 sensors looked normal, and there were no fault codes. I'll gather some more data during the next run.

I can't wait to get in the drivers seat and drive the sh**t out of it. ;) First things first though, change the oil filter, top the oil off, and bolt on the cross members, heat shields, cowling, and bumpers.

I have a good 2 mile straight stretch of 10% grade nearby where I should be able to really open it up (prob. keep under 5k rpm, but loading the engine heavily in 2nd or 3rd) and also get some good engine braking on the way back down for hill repeats. Here are the break in recommendations from LNE, and I'm not using a dyno:

http://www.mototuneusa.com/break_in_secrets.htm
http://www.aircooled.net/gnrlsite/re...s/engnbrkn.htm

I'll post some videos from the drivers seat during the first road test/break in.

Once that's done, a couple hundred miles later the oil and filter will be changed. I'll probably be using Valvoline MC 4T VV740 10w40 (perhaps a couple changes) before switching to synthetic.

And after that... I'm also dying to know the results of the 3.6L bore. is there anyone in the Reno/Sacramento/Bay Area that would like to donate some dyno time or make some recommendations? I'll provide the beer, or chips, or cookies or whatever! :) :) :) :) :) :)

i'm not! you take 'anal retentive attention to detail' to a whole new level! :-) fantastic job taking your time to ensure even the tiniest operation was carefully considered. thank you for documenting this so well for us! have fun.

Excellent, I love it when you get to the point of the "moment of truth" and start the motor. Very rewarding! Job well done. I will use this as reference for the day I need to do some internal work to my motor. Enjoy the car now!! :cheers:

Well as if to say "you forgot about me"... I discovered a problem!

I was going over my notes from yesterday and saw the IATS of 61C. Wait... 63C? 145F??? No way is it that hot in my garage or the airbox for that matter !!!

Thanks to Loren's help, I ohmed out pins 1 and 3 on the MAF and sure enough it's not in spec and appears to have a short. It's only 61F outside (16C) and appx that in the airbox. Installed the MAF in the car again and it started reading at 19C, then while leaving the ignition on (engine off), it slowly started creeping up on it's own to 20C, then 21C, then 22C, and it certainly isn't 72 degrees today.

Good thing there are cheaper alternatives on ebay, pelican, and amazon to paying $600 the dealer wants for a new MAF.

FYI. Much cheaper source for MAFs.

http://www.autohausaz.com/search/pro...0Mass%20Sensor

Thanks Chao. Hows your car running after all that work you had done?

Logan,

My car runs great! The one thing you will notice is how much smoother the car pulls but with authority. I am curious to see what your dyno numbers will be. Shoot, I will pitch in for a case of beer to get your engine dynoed...

I have not driven my car for about 8-10 weeks and its sitting in the garage on a battery tender. I am thinking about selling it even after saying I won't because I want something else. Maybe, I will change my mind again after I drive it. Choices choices...

What are you thinking about getting?

Not quite sure but looking for the right 993TT. My wife gave me the look when I mentioned it and said I should have not have dropped the engine for maintenance work last fall. I see it as a huge plus for someone who is looking to pick up a high mileage 996. Call me a fool. Anyway, back to regular programming...

Logray, excellent writeup, congratulations on your success!

There is a saying that I am sure you have in the US too (sorry for any translation errors): Luck is strangely enough always on the well prepared persons side!

With your attention to detail and more importantly constantly questioning your work I am not surprised about 0 problems to follow up. Great! Myself is more prone to rationalizing my work instead of questioning if I did it right, and I have NEVER had 0 problems after an engine rebuild....

It is a true inspiration to see that a "normal" guy actually can both rebuild and improve the insanely complicated flat 6 that Porsche produce.

Good luck with the break in driving!


Thanks,

Johan

Sounds good - I'd love to hear it rev past 5K when it is fully broken in!

It must be a great feeling of accomplishment when you do all this yourself. It reminds me of building my first PC back in the 386-25 MHz days - piecing together the parts from different suppliers. PC building on your own back then was a bit more difficult, the parts were not as much of a commodity as they are now. There are some parallels in these two worlds.

Love the video. Sure sounds smoooooooth! Keep them coming.

Thanks guys.

Also I thought I might share this article I fished up. In addition to the motoman and aircooled guy's break in web pages I posted earlier... (from LNE's oil bible) I found it interesting the shell aviation Lycoming and Continental horizontally opposed engine break in procedures to be surprisingly similar... a good read for any gear heads out there (warning technical content):

http://www.shell.com/home/content/av..._30071255.html

Ya gotta be happy with what you see. I hope you are developing a really big grin now when you take it out.

Indeed I am, honestly I cannot drive it enough. :) :) :) :)

The next oil change will probably come sooner rather than later. I'm trying to come up with an excuse to take a long road trip.

It is great that you keep reporting your first oil change ! I always wondered how much ferrous deposit would be in a new engine :) now we know !
Did you open your oil filter ? I think you now have one of those metal ones so I wonder if you are gonna go through the headache of opening those.

Keep it up... it is almost like this engine is ours :D

Out of curiosity, have you tallied up the entire cost of the rebuild? I know you did the heads months ago. I have 130K on my engine and have been thinking about a 3.4 to 3.6 rebuild/upgrade.

Was the magnetic drain plug able to get all the ferrous parts or did you also pick some up in the oil filter? Any signs of plastic actuating cam pad materials? I have not changed my oil after the overhaul on my car so was wondering if you saw some in yours.

Total cost was somewhere around $12k, including machine shop services, parts, and the valve job from the previous build.

No, there were no cam pad pieces. I believe I read that the latest material Porsche uses for these pads stands up to the test of time better than previous materials. All 4 of the variocam actuator pads I installed 1000 miles ago were perfect, and I just re-installed them. While I did the rebuild, I replaced the other 6 pads/ramps/guides as well.

I didn't crack open the filter, but I certainly will, I wouldn't be surprised to see some stuff in there. It's a metal filter from Napa. I need to buy one of those filter crackers.

Longacre makes a great filter can opener. Works kind of like a copper pipe cutter. 50 bucks or so but its really slick.

Logray, I all ready have some displacement envy :D

I changed my oils 3k km after the rebuild. I had no magnetic drainplug but there was no debries in the oil.
But in the oilfilter, there was some metal and small pieces of gasgetsilicon. Will check the filter again in next oil change, but I'm planning to drive 10k km with these oils.

I didn't use any breakin oils, becouse I had no work done to the cylinders....

What is the theory behind why you use a different oil for break in?

Hah T, very funny... are you still looking at moving "up" to a 997 ?

As for the oil question, the synthetic stuff is just too slippery and doesn't have enough ZDDP for proper break in.

Break in oil is often regular ol' straight weight motor oil with a huge dose of ZDDP and other anti- scuffing additives to help promote rings seat/seal and enhanced wear protection. You don't want to run break in oil for very long because it can damage cat converters. Also in the case of brad penn, it's not a multi weight oil, so although it performs just like a 5w30 weight once it gets to operating temp, when it's cold it doesn't flow as well as a 5w30. It's not designed to be used year round, in other words. I think Joe Gibbs offers a multi grade break in oil.

You want to wait until the rings are good and mated with the cylinder walls before going to the synthetic stuff.

In the case of this engine, to ensure the rings are seated quite well, I might do two changes using non-synth motorcycle for about 1500-2000 miles worth of driving until I change to synthetic.

Also just for fun I'm going to send in the break in oil for UOA.

Hope the injectors are the answer!

Good job documenting the process, fun to follow.

Hope it works as well! Interesting you had to trim them. I was able to confirm the 3.8 injectors will work on my car.

Why not run a oem 996tt fuel pump as well?
Do the 3.4 and 3.6 use the same bar fpr?

The 996tt fuel pump prob wouldn't work, since its designed for AWD gas tank. Also, the pump I'm running is specified for a 2001 3.4L which are also matched with the injectors I'm running now too... the newer C2 996 pump has an integrated fuel filter and I can't remember if it is returnless or not. I'm not sure it would work either.

Good to hear the 997 injectors will work for you Carey.

Good news about the fuel trim issue!

After replacing the injectors I put about 50 miles on the car. The long term trims went back to their usual 1.08+ and short term down to -0.11 (and continued). At this point power was down and idle was rough.

Frustrated, I cleared the fuel trims again and re-installed the new MAF (previous 50 miles were with old MAF). Put another 125 miles on the car, FRA remains solid at 1.03, and it wants to tick over to 1.01/1.02. TRA remains solid at -0.03. Injection time has decreased so certainly it has helped. To summarize:

Old injectors, new MAF = not good
New injectors, old MAF = not good
New injectors, new MAF = good

So, the fuel trim problem appears to have been solved, but I still need to add more miles to verify. The figures are well within spec, and the car still has tremendous power and runs great (even better than before with the old injectors) HOWEVER... (getting tired of howevers)

There is still a third related problem, once the car heats up, it still runs great, and idles great EXCEPT on a hot re-start it idles very poorly randomly, barely able to hold 680 RPM idle with no loads (stumbles a little as it dips lower) and then the ECU changes timing/adds fuel etc and gets the idle up and holds it steady and smooth for a long time, but will occasionally lose the 680 or 720 rpm and stumble again. In fact, it actually stalled on me at a stop light once. Once there is a load (A/C, fans, etc) it immediately smooths out again and can hold it indefinitely. No codes, of course, I'm dying for a code but the DME doesn't want to offer me any help. ;)

I watched the rough running values and they don't go above 2.0, but they are pretty random and between 0.5 and 1.2. Ignition timing is a little across the map too when this happens. It is still very very smooth though when it is not going through one if it's stumbling fits. And it never does this at RPMs above 700 (although rough running does still register occasionally and randomly).

So I am thinking this is a DMF, cam/crank position sender issue. While the DMF springs still tested out per the TSB each time I've had it off, perhaps there is an issue with the reference mark magnet or a toothed segment (although I did inspect before re-installing). I'm hoping it's just a crank sender issue.

I ohmed out the crank sender and it is only at 839ohms. Reading rkellisons post he measured new @ 938KOhm and old @ 915KOhm. I think he means ohms, not k ohms, since the spec for a "good" crank sender is 0.8k to 1k ohms. Mine does fall within the range of good, albeit closer to the "out of range" spec and is apparently "tired". I might test it again once it heats up, or artificially heat the sensor, since that is the only time the issue is present. At about $100 online I might just pull the trigger on a new sensor, even if it doesn't fix the issue.

I'm trying to find ohm specs for the cam position sensor, can't find them anywhere. They are a PITA to ohm out anyways, might just see if the crank sender fixes it first before diving in to that. I have observed bank 2 deviation after DME (battery) reset is "slow" to read, and sometimes it "settles on" +2 deg and sometimes at +3 deg (but once it "reads" it doesn't move from there, so there is no worry of slippage, I know it is mechanically sound). I could swap the CPS between banks, but at another $100 for a sensor on top of the $12k I've spent on this project I might just buy one of those too. I think though I will tackle the crank sender first because it's easy to get to. Perhaps it is co-related to the bank readings since the DME might be having trouble reading TDC and therefore affecting where it reads cam position as well.

I'm hoping this isn't the DMF, that is only slightly more involved (and expensive of course). :@

Getting very close to calling this one "done" and ready to throw on the dyno. :)

Great job and great thread. Thanks for all your pictures and documentation. Very cool to watch you through this process - it's something I could never do myself - you must feel really good about yourself as you should since you say you are a shade tree mechanic/non-professional. It's like one of my desktop users @ work telling me they re-installed the O/S on their work computer on their own without my help - I would be shocked.

Check / clean the Idlecontrolvalve, mine was stuck after rebuild.

Just a tought.. :)

Thanks guys again.

I've removed and cleaned and dismantled the IACV since the rebuild. For anyone who hasn't done this it's surprisingly easy to remove the pin, then twist the magnetic part from the control half and get the insides very clean. Anyhow, yes is very clean and I don't think it is causing this problem. The IACV makes the big adjustments, and the computer makes the smaller ones with timing. The ones that are happening here are problems with the smaller adjustments.

When it goes through one if it's hot idle fits, the ignition timing is fluctuating a little more than normal at idle, and when it stumbles the engine just ramps up the RPM a little, the idle smooths out, and the transition is very smooth, so if it is using the IACV for a larger adjustment it is doing it's job correctly (or the DME is just using timing advance to compensate).

After even more driving (I think I have like 800 miles on the car now since rebuild) the long term fuel adaption has gone to 1.00 for both banks. The power is just phenomenal, I wish I would have done the injectors and new MAF from the get go. It really feels like it's supposed to now. Magic happens above 5k RPM.

Interestingly, the idle fuel trims remain slightly negative, -0.05, but this time when it's stumbling at idle it doesn't seem that it's because of a lack of fuel sensing rich running (with negative short term trims down below set points at -0.1, nearing -0.2). And of course these readings will adjust based on driving conditions. I'm very confident the fuel trim problem is resolved. I'm thinking the problems apparent might have been compounding, the DME perhaps retarding timing because of the idle ignition timing issue, MAF issue, weak injector issue all the while pulling back even more fuel until near CEL status, which I'm sure would have happened if I didn't address the fuel trim issue.

If you see the other thread I've started I'm starting to lean on an issue with cam or crank position sender or flywheel.

What is interesting, something I've noticed since owning the car for 5 years is after a DME reset the cam deviation values take a while to adapt. Bank 1 deviation doesn't move at all and seems to "learn" more quickly than bank 2. Here's what I've observed paying closer attention to the detail. From the other thread I started.

I'm starting to think it could be a cam sensor issue. The cam deviation values for bank 2 are being misreported each time I reset the DME it takes many drive cycles before it "stabilizes". When I first fired the car it read 0 as it always does and then moved to 3 for bank 2. Bank 1 seems to learn more quickly and settles on 3 degrees (hasn't moved yet). Bank 2 initially after DME reset reads 0 degrees and takes while to register but then moves to 1 or 2 or even 3. Still, until enough drive cycles are complete it even will go back to 0 degrees and sometimes even blip to 1 degree at idle, but when in gear the value doesn't change. I'm wondering if this is because of an issue reading reference marks from the flywheel or crank sender. I might just bite the bullet and order up a new cam sensor. I could swap senders between banks, but that is a major pain in the ass since I have to remove the AOS. I would much rather just remove the air con compressor since that is a whole lot easier, and fortunately the sensor (or bank) that is having the issue reading timing.

If I still had my PST2 I would disconnect the bank 2 cam sensor and reprogram to ROW and see if that solves it. Darn. Shouldn't have sold that thing so soon. And on this subject my spare DME exhibits the same issue as well, so I've ruled that out (and also ohmed out the wiring and read 5 volts going to the cam sensors, and ohmed out the crank sender, although that is still suspect).

The actuators and solenoids are brand new, the cam sprockets are one piece, torqued to factory spec using blue loctite, the timing was set using the factory timing tool, the IMS tube received a new LNE ceramic bearing, the teeth on the IMS tube were fine, the chains are all new. I'm confident it is mechanically sound, unless the issue with the CPS is co-related to a problem on the camshaft, perhaps the reference piece has a problem (although I doubt it).

Here's that thread regarding troubleshooting the flywheel:

https://rennlist.com/forums/996-foru...ired-easy.html

Great news!

Glad to hear you have it all sorted out. Can't wait to see the dyno results.

Great to read the end of the rebuild. Chasing those last few bugs must have taken some persistance after all the work you'd done.

You should be able to stick the foam chunks back into the seat with white glue!

Cheers, Ben

Good work Bud! Looking forward to dyno #s... Ive put about 550 miles on mine so far. I cannot wait to unleash it on the track.

I can attest that logray's car feels like a turbo.
Without the lag. Impressive!
Now I wish that I had Jake do a 3.4 to 3.6 build last year, even tho it would have doubled my bill.

logan great to see a great ending to all of your hard work. Enjoy.............

This car is so unbelievably fun to drive again I can't even describe it in words.

The alignment was the icing on the cake. I can't even believe how great the car is, it is totally sorted, and just has more power than I'm comfortable using on the street. I'll have to get it out to AX this spring.

After cancelling the first dyno appt. so I could resolve some issues, I've been shopping around again. I failed to ask the price of the first recommended place, which turned out to be $200 for just a couple pulls. "No tune" I tell them, just want the numbers. "well we have to set it up the same either way, so we're charging you the same". Argh.

There are no less than 5 shops with "open" dyno's in the greater Sacramento area, the one of which who actually works on Porsche's "doesn't do dyno pulls" anymore.

The rest all want between $150 to $200 for just a run or two. Seriously? Are people that desperate? Just because I have a Porsche badge on my hood ???? It seems like a lot to me to strap the car down and stick a couple probes in the tailpipes. Maybe they have a big insurance bill to pay.

Now we just need some good driving weather! First Sac Valley Region autocross is 4/22...

If you get exact weight of your car and can log acceleration with a gps device, you can work it out. Aero drag can also be worked out as we know the Cd (or just assumed).

I just paid $125. at Stillen for 3 runs on his DynoJet !

What is the correct resistance for the iacv? I've been hunting for the cause of a slightly rough idle.

S.

The Dynojet up at Thunderhill is $75 for 3 pulls with A/F ratios IIRC....

Awesome, thanks JR! Willows is pretty close to me. I'll call them up today. ... also I noticed they have an open track day TODAY!!!! $250 for the full day. Too bad my 996 isn't race prepped. Hmmmmm.... ;)

uber: IACV winding and ohms: http://www.renntech.org/forums/topic...new-cel-codes/

How could you resist??? Bring a helmet and turn some laps! Im hitting the track Saturday. :thumbsup:

I know... too good to be true... but I would have to "sneak" past inspection without an extinguisher, cage, & kill switch.

I just looked up the dyno info at thunderhill, only $60 for three pulls! Now that's more like it!

http://www.mcedyno.com/MCE%20RACING%20-%20Pricing.html

They require a a cage and kill switch for a DE? That's crazy... what club is this? no way to "sneak" past if that's the case.

It's an open day for race prepped cars only today (no street cars)... not a DE... they do have OPEN days though sometimes for street cars.

Dyno results from a awd dynojet. Not entirely what I was expecting.

Stock intake, stock air filter, no porting. Fabspeed headers, 3.6L stock mufflers. Maybe it can't breathe well enough. I have a K&N I can throw on there and also have a Softronic ECU tune I can install.

Something doesn't look right, and my butt dyno agrees with me. Sure sounds good though. Watch and listen to this thing scream !!!!


https://lh3.googleusercontent.com/-a...s1280/dyno.jpg

Must be a conservative dyno. Feels stronger than that. Is it fully broken in? It's screaming for an exhaust!!

1300 miles on the rebuild, I would think most of the break in is done by now.

Either I've stunned everyone with monumental numbers or all the gearheads are over in the racing forum. :)

I did a little analysis, if someone wants to check the numbers.

------------------------------------------------
Stock 3.4L numbers from the WSM:
------------------------------------------------

300 din @ 6800 rpm (2000-2001 year engines)
296 din (1998-1999 year engines)

After LNE 3.4-> 3.6L upgrade
Measured 264.12 ft/lbs dynojet SAE rwhp

@ 20% loss, 317 SAE FW / 321 DIN / 325 STD
@ 15% loss, 304 SAE FW / 308 DIN / 312 STD

Depending on drivetrain loss, a gain of as much as 25 DIN HP over a brand new stock 1999 3.4L after the 33.33 cc increase per cylinder !!!

Certainly my 3.4L was NOT making 296 HP before I took the knife to it, so my actual gains are much higher (no I did not dyno before the rebuild). It was both tired (150 compression) and sick (cylinder contamination).

------------------------------------------------
Stock torque numbers
------------------------------------------------

258 ft/lbs @ 4750 rpm

Measured 225, a very flat 200-225 mind you, which certainly mirrors how the car feels, pick any gear at any speed above 3500 rpm and you can't go wrong. :) :) :)

But certainly not 258 the factory measured from stock. This was unexpected and a little disappointing. Maybe the aftermarket exhaust manifolds are hurting, or lack of complimentary intake mods. Maybe they picked the wrong gear for the pulls.

-----------------------------
AFR
-----------------------------

Looks suspiciously perfect to me.

Maybe the engine was too cold, or maybe it's time to do more mods!

Any thoughts?

What gear was used on the dyno??

I had my car dynoed before the rebuild and got 255hp on the wheel's on 5th gear.
4th gear pull was 243hp on the wheel's

Looks like you are in the ballpark .If we take speed r II dyno number of 255 and and compute drivetrain loss - 255/296=86 % or 14% loss .
This will be controversial-996 power factor 3400cc/296=.087
3600x.087=313.2 at the flywheel or 313.2x86%drivetrain loss=269 rwhp
The logic is that the only thing that has changed (so far) is displacement .Therefore it should be a pretty good relationship and the power factor is a reasonable yardstick .
Three things come to mind -200 cell cats -Jakes cams and a DME adjustment .A goal of 100hp per liter sounds about right .Assuming the heads can support the required flow .

Your TQ numbers seem low compaired to Prodrivers. Did you install a new clutch plate? Or maybe your tires were slipping a bit?

SpeedrII, it was done in 4th, I'm pretty sure that's the standard. 5th would spin the wheels awfully fast, maybe 150mph+ in 5th at 7000rpm? I'm just saying maybe they picked 2nd or 6th, I doubt 6th though because it would have taken forever to get to 7000rpm and would have noticed the problem right away. After watching the video again I think it was 4th, 2nd would have spun up really fast, and the spoiler would have barely deployed at the top end of 2nd, it came up well before that.

Tusler, yes the torque numbers are a little low :(. Yep, new clutch disc with about 250 miles on it (and I went through break in with it already, no sense of slippage on the road at WOT after break in). Not sure about tire slippage but they certainly had it ratched down well with about 8 straps between front and back. The rears were at 44psi and it was a 55 degree day IIRC.

drechel, I agree, I think this is ballpark for HP and I'm quite happy with that, just that the torque numbers seemed slightly low.

I think with porting, ECU, and CAI I could probably squeeze out a few more. Maybe I'll throw the K&N filter in the stock box for a little more sound (it is awfully tame now compared to how it used to be with the full fabspeed it).

But I think I am very happy at this point, and I'm not going to change anything major with the car, just drive it and enjoy it !!!!

One area that could unleash more of the engines potential is the throttle body .I thought I read that the 3.6 was using a larger bore .Plently of places provide that service -especially in California .
One again thank you for sharing the build and the all the pictures .It has been a terific education and most interesting .It will be boring without your project to track .
Dave

OTH the TQ stays up nonce up and thats a good thing.

Is your TB the cable operated one? Measure the ID of it and if its smaller than 74mm. I have a spare 74mm you can try out.

To my knowledge, cars should be dynoed on the gear that is closest to 1 ratio.
On 996 it's 5th gear... I bet that you would gain some hp if you dyno the car again with 5th gear.
Wheelspeed is high, about 240km/h. If the dyno allows thesekind of speed's I would do new pull's ;)

+1 :thumbsup:

Was the dyno inertia or brake dyno?
I believe that inertiadyno will show lower torgue figures allso, if dynoed in too small gear :)

FWIW I think you're choked up. The stock mufflers are extremely heavy and congested. An after market system, perhaps Fabspeed's, would expand your new motor's ability to breathe. Stay with the stock air box but switch to a better element, I use BMC.

4th gear is where most stock geared Porsches dyno. Mine have always been in 4th....

Here's my latest dyno sheet on a Dyno Dynamics machine. They produce considerably lower results than a Dynojet, many say 10% less. I'll have to get on a Dynojet if I want to race with NASA this year. I'll probably go to a 2.5 TB and hopefully get the WHP down to 270 or so.

Our motors are significantly different, you use the larger Nikies cylinders to get to 3.6, I used the 3.6 crank and rods with decked 3.4 heads, cams, and a 5 angle valve grind. I also have 3.8 manifolds to straight pipes, FVD's slightly enlarged throttle body, and GIAC's street flash. YMMV....


http://img585.imageshack.us/img585/3429/dyno1e.jpg

Uploaded with ImageShack.us

Thanks for the offer! I remember looking at FVD's 76.4mm body years ago when I did my Softronic flash. Unfortunately, right around the time I bought the flash, Scott stopped supporting Motronic 5.2.2. Took my money and ran with it!

My T/B is stock cable op at 74.8 mm. Are you sure yours isn't 76.4mm? I don't remember a 74mm for the 996 (1998-2001), except maybe on a smaller Boxster engine. I'll send you a PM.

I would be open to throwing it on and taking it to the dyno again, which I'm starting to get the itch a little to see what was up with those torque figures.

I'm just not sure how much it could help without complimentary intake and exhaust porting. Heh maybe I could get out the dremel like speed rII did. ;)

Interesting, even hte dyno operator Kevin noted it should be done at gear closest to 1:1 ratio. After looking at WSM, 4th gear is 1.22 and 5th is 1.02. The machine I used goes to 180mph which is about 150mph. It might take some convincing though, to get this machine spinning that fast.

It was an intertia dyno. A dynojet 424 linx, link below. As for higher numbers, I would want to see whatever is comparative, but it would also be interesting to see what it could do in 5th gear.

http://www.dynojet.com/automotive_dy...o/default.aspx

I concurr... I'm guessing a lot of the problem with mine is on the intake side, with the stock box and stock filter, 3.4L T/B, and 3.4L porting. In fact the long term fuel trims have gone a little negative with the 3.6L injectors, which might indicate the same thing, less air means less fuel right! And that AFR graph might also indicate boring-ness happening inside. You're talking to someone that used to have EvoX CAI, IPD plenum, fabspeed headers, cats, and mufflers. I also have a K&N for the stock box I removed long ago while troubleshooting my MAF. But I think I'll throw it back in just for fun. I could have the fisterD mod done on my 3.6L stock muffers, at least shipping would be cheap since he's close to me. I think I would stop at fisterD though.

I'm contemplating reflashing my DME with the softronic flash, but without any support or much info from Scott on what he "tuned" I'm a little hesitant, don't want to do any damage. The first time I bricked my DME I had to learn how to flash it on the bench, now I've flashed 3 times on 2 different DMEs without issue (both PST2 and Softronic). The 5.2.2 is difficult to flash and some of the original models had bad NVRAM.

No doubt your other mods are exploiting your upgrades, the straight pipes and the throttle body. My valves also had a grind FWIW...

I nearly forgot about plugs too... geez the snowball certainly gets bigger once it starts rolling down hill.

You're right I just measured it and it's 76mm. I think FVD opens them to 78mm? Not much thickness in the wall.

PM sent on the larger T/B. Yes FVD goes to 76.4mm.

I tried looking for the 3.6L throttle body specs but couldn't find them.

For sure I think this might help, if the stock 3.4L head ports can handle the extra volume. Considering I've got the 3.6L mufflers and aftermarket headers, I am thinking this would help including the K&N w/ the stock air box.

I don't want to go crazy with mods nor tear into the engine again at this point, but I wouldn't mind giving this a go and maybe putting her back on the dyno to see if it can breathe easier.

Anyone out there know off the top what the 3.6L T/B measures out at (or would like to measure)?

Forgot to give you A/f ratios.....

http://img407.imageshack.us/img407/7945/dyno2s.jpg

Chew on this... The GT3 RSR has to breathe through a pair of 29mm restrictors. It makes 460 hp. Max. torque: 430 Nm at 7,250 rpm.

http://911nation.com/wp-content/uplo.../normal-10.jpg

Did you ever get this resolved? I've done the exact same thing that you did, with the exact same build, (threw a rod twice on the track, so two rebuilds) and I couldn't be happier!! What a machine it is now! (I actually did a bit more, single mass flywheel, Accusump, Oil crap, Tranny work, etc.) --- BTW, Love your head bolt idea, will do that next time I tear it apart.

What is driving me bonkers though is the idle. :to_order: Since the car mostly plays on the track, it's not too bad of a problem, but I still have the original stock seats, and would like to drive it on the street more.

LOL!

YES!!!! I did fix it!!!!

It was a combo problem. My IACV was toast, the open winding was only providing half the resistance (this was the biggest contributor). But other things that were contributing: I didn't upgrade the injectors when I upgraded the displacenent (leading to a computer induced rich condition, and even though I had swapped the injectors for larger ones the computer hadn't learned yet, it needed a reset and was still dumping too much fuel), my MAF and CPS were also marginal. ALSO, make sure you don't have any vacuum leaks. I didn't, but did a very thorough check.

Now it PUUUURRRRRSSS at idle, but I don't spend much time there (I like the other end of the tachometer better). ;) :burnout:

Oh, forgot to mention those 3.6L cans I bought from a RL member, one of them has a broken baffle inside and squeaks/rattles all over the place, so this winter it will be off to Dr Fister D for repairs.

logray - hope you stillpost here

where did you get the torque specs/sequence for all the different bolts? manufacturer recommendations?

Havn't seen Logan here for a couple years. Try Renntech's forum.

Logray - Thanks so much for undertaking this detailed writeup ! This is an Awesome and valuable thread to a guy like me: below is why....I am not sure my below warrants a new thread (I am not sure how forums work to well...I am kind of new)...but I am looking for 1) crank specs 2)feedback on my choices.

thanks
************************

I am rebuilding a 997.1 3.8L S motor (D-chunk crack cyl 5) into a 4.0. Likely failure was a gel slug behind the water pump (wrong coolant added?)....Oil was chocolate milk mixture. (bought it this way as a project with 100K miles on it); could be gel slug was from coolant added after Dchunk failure and low coolant showed....I will never know.

Cases are coming back next week from LN Eng with nickies and JE pistons. IMS solution also being installed in the rebuild.

This will be built for street...no plan to ever race...so following decisions were made (I am open to hearing advisement if you disagree on any decision or have opinions)
1) stock rods will be reused (new bearings)
2) Using NEW OEM bolts everywhere (connecting rods, head bolts,crankcase carrier bolts etc.....I was advised if not racing..then ARP would not be needed...only really needed for the high RPM abuse of racing)
3) replacing water pump
4) Undecided on LN eng billet timing chain guide ($330) vs stock ($40) since not racing...might do it anyway for "insurance"...since it is deep in the motor)
5) all new chains and guides
6) heads were inspected at a shop..they stated guides were good...just changing the seals and resurfaced them
7) all new oil separators
8) reusing oil/coolant heat exchanger (they seem to be a suspect part from what I read even when bought new they are no always good...so if it aint broke on that one I dont want to take a chance on replacement)
9) Bought wrist pin insertion tool..plan to grind wrist pin hook away (I read this is the flat six approach) on cyl 4-6
10) will weight and match all opposing pistons+rods+rings+bolts+pins+clips for best balancing
11) Undecided but probably will send crank and all parts to shop for professional matching(to confirm my work) and crank balancing/magnaflux (This is not where this motor had a problem..so I suspect magnaflux is not needed...but insurance again comes to mind))

...lots of other smaller decisions made...but above are the bigger ones or not fully decided ones to give folks a flavor of the project

REAL question for why I am writing...I cant for the life of me find specs for 3.8L crankshaft! Info is not in the WSM. Trying to confirm Journals are in spec for standard main bearings or not so I can make my big parts buy for the rebuild.

Below are my measurements:
Crank Main Journals: Average =62.992 +.0432 / -.0292 (Max=63.03518; Min= 62.96279)
Crank Rod Journals: Average = 52.98794 +0.018 / -0.0131 (Max=53.00599; Min=52.974875 if too many sig-figs please disregard. I measured in inches the converted in excel to metric..not sure why I didnt just do metric....I am just not used to metric.

Full Disclosure: I am mech eng...but this is my first engine rebuild..I will take a few deserved lumps on this not so smart choice to make a $20K porsche high performance motor my first build....I deserve that:-); restored various previous cars and done engine swaps...just never did an engine...but I am having loads of fun!

For everyones interest Pic of Gel slug and D-chunk crack are included here Since I havent seen many when I was looking. (I do videos talking to myself for future reference...not pictures...so sorry for quality)
https://forums.pelicanparts.com/uplo...1570338669.JPGhttps://forums.pelicanparts.com/uplo...1570338917.jpg