Charles Navarro

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.

nick49

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.

logray

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.




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.

babylonboots

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!

logray

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.

Byprodriver

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

logray

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.




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.



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 !!!!!



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.

speed rII

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

jrgordonsenior

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....

logray

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.



New washer and clip installed for the LNE billet paddle.



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



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



Bearing carrier dropped in.




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




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).

logray

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"

rb101

engine ****....love it

logray

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.

Charles Navarro

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.

logray

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"