logray

Yes, I believe a CEL would pop if it is out of spec.

Yes we call it SMOG test here in California. Unfortunately even though they probe both tailpipes, they do not differentiate in the report.

I don't have the test results from 2007 and around 42,000 miles unfortunately when the car was sold to me.

Here are the results from 2009 and 60,123 miles. This one is a rolling test which also measure Nitric Oxide.



Here are the results from 2011 and 72,303 miles. I had the emissons test done a few months before the valve job where there would be plumes of blue smoke at startup plus a lot of blue smoke at RPM, then off the gas. This test was done in an area with relaxed emissions standards, therefore it did not go on the dyno, nor did it measure NO.



Note that the HC went up from 9 PPM in 2009 to 17 PPM HC in 2011, whereas CO2 went down from 15% in 2009 to 9% in 201. O2% went way up from 0.1% in 2009 to 9% in 2011. CO% very low in both years. OF course, I'm not sure if those comparisons are valid because one is a rolling test on the dyno and the second test is a standing idle test.

Perhaps I could pay for a test and have them only probe one tailpipe at a time to see what they get. Do you think it is worth it?

Also here is the latest oil analysis, done right before the valve job:



Here is the fuel injector report in a more readable format, they were cleaned during the valve job and reinstalled in random positions:



As for the unburnt fuel or oil though, can you think of a definitive test to determine whether it is oil or fuel burning? The smog report doesn't show that as far as I know.

And THANK you for the ideas!!!! Keep them coming! Yes the car drives marveloous, certainly down on power from when I bought it, but there really is a ton of soot coming out of bank 1's tailpipe that is a cause for concern.... don't want to ruin my spark plugs, cat, 02 sensor, or keep putting in new plugs every 1000 miles.

Thanks David, a free leak down and compression test huh? I would be up for that. Well I'm up near Auburn, CA so SJ is a fair bit of a drive from here but I certainly appreciate the offer and will keep that in mind!

rb101

When you did the compression test, was the throttle plate blocked open? I find it odd that all the compression numbers is equally off.

jsoderbe

Hi, that s interesting, your smog test is the same as we do! Even the same limits!

Just out of curiousity, how did the sleeves look when you rebuilt? I would guess you had a look for scratches or damages? Was still the honing scratches present?

Anyway, I am not sure how important an exhaust test from both pipes really is. Can you have that performed unexpesively? I mean, if you can see the actual soot coming out, you would have a HC of way way over 100 on that pipe. On the other hand, if you get for example a HC of 400 on the sooting bank, and 2 in the other, at least you know you can't drive it any more without damaging stuff.

And the spark plug seems to be oil fouled, even though I really want it to look like carbon, it doesn't. So I agree with your sooting problem most likely being from oil, but in my very non-expert opinion, the leak down and compression numbers does not support ring problems on just one bank.

Maybe you could try to get as bad compression numbers as possible? Meaning, if you test it cold without full throttle, maybe you could get the numbers to support what you believe is the problem? At least I would feel better about sinking 10 grand in it, if I knew the actual problem was going to be fixed.

And again, I think the 3.6 route is the right way to go, since it will increase the resale value.


Thanks,

Johan

logray

Yes throttle plate all the way open, all spark plugs removed. Compression for each cylinder were all around 149 to 151.

logray

I really do appreciate the comments, thank you!

The sleeves were smooth as silk. I could find no imperfections by feel and saw no scoring or damage. I did not measure the bore size or to see if it was oval (I don't own a bore gauge). This was the only imperfection I could see out of 6 cylinders, and when I ran my finger over that mark it was completely smooth.



Here is the thread for the top end rebuild if you are interested.


https://rennlist.com/forums/996-forum/644150-1-rebuilt-engine-1-month-and-325-pictures-later.html

Yes I could have each side tested for about $40, perhaps I will do that as well. I can't see the soot come out, but if I hold a clean white rag over the tail pipe it takes a few minutes and then I can detect a small amount of residue there. If I wipe my finger in the tailpipe, there is a little bit of oily residue that shows up on my finger. During the rebuild I had cleaned it so that it looked as clean as the the tailpipe for cylinders 4-6. After just 100 miles of driving, the bank 1 (right) tailpipe was completely black.



But bank 2's tailpipe still clean as a whistle.



Yes I agree with you the deposits on the spark plugs in bank 1 all have oil residue on them. If it was too much fuel I've always been read that the carbon will be flaky and dry. In this case it is oily when I touch it. I agree the leak down and compression test results are annoying to say the least.

But I'm starting to believe we can't expect conventional results from this engine. I am wondering if those numbers are just misleading us. We heard earlier in this thread that it can be common for the engines to lose ring seal early on, or that the cylinders oval. Perhaps it is normal for oil to leak through the rings but still get even (but low) compression numbers and descent leak down results. Here is what Mr. Raby had to say earlier in this thread:

"Its absolutely possible that the engine has lost ring seal on all 6 cylinders- we see this all the time. The cylinder composition of these engines does not yield conventional symptoms or behaviors...It is possible that the cylinder issues preceded the issues that lead to the heads being removed the first time around...I have seen engines with as little as 27,000 miles lose ring seal for no reason, having been perfectly maintained and never tracked....With that low of compression ... I'd say this is a classic cylinder/ring seal issue. Thats the reason why we don't even take that risk and replace cylinders, pistons and rings with updated versions....It won't get any better, thats the cold heard reality of it.. If the leak down numbers were half that much and the compression numbers were at least 185 PSI it might wake its self back up again, but those numbers are very, very poor."

I might repeat the compression test but this time squirt some oil in the cylinders. If the numbers go higher, that means the rings are sealing better temporarily with the oil present. Then again, if this engine doesn't behave like most others...

Unless anyone has any other ideas for tests one last thing I might do before I drop the engine again is test for fuel delivery quantity and pressure.

I'm going to take this in steps, it's going to take time to spend the $7,000 to make it $10,000 for the whole rebuild (the LNE 3.6 upgrade take 4-6 weeks by itself, but there is a lot of work before I get to that point). And some of that work might involve taking a closer look at the #1 head before I open the case. If I could find the problem there, I might put it back together... even though compression is low... tough to say though - a lot of it also depends on how much money I can raise.

dcdrechsel

The link below provides some very good info on locasil and a short discussion on rings .Just thought you might be interested
www.electrosil.com.au/KS.pdf

logray

Very interesting link. Thanks for the read on Lokasil.

I thought it was interesting they say that much like Hartech has done in the UK, they go on to say that overboring Lokasil and weight matching with replacement pistons is certainly possible (given there is enough of a market for it).

I wonder how much I would really "save" though finding a shop in the USA that would do this and then have custom pistons made... versus just going with the LNE 99mm bore Nickies w/brand new JE pistons & rings.

Also where was the section on rings?

Flat6 Innovations

I've never seen any good come from JE or any other piston inside a stock bore.. The last ones we saw failed horribly in less than 100 miles.

Are you going to keep the car or not? If you like the car and want to keep it you are really creating a lot of work and drama for yourself. These cylinders are VERY particular and the first thing we learned about with these engines was not to play with fire concerning them.

More than likely your bores are not straight or round, especially the center cylinders (2 and 5) as most ear not. Cylinders that are oval or tapered over work rings and have horrible sealing characteristics.

Great success or epic failure awaits you; there is no mediocrity associated with the M96 cylinder explorations.

logray

Thanks Jake.

I'm about 90% certain I will keep the car and do the rebuild.

The only solution for the rebuild I am considering at this point is LNE's Nikasil rebore. Although I enjoy reading about and find it very interesting the different options out there such as cast iron, overbore, and Nikasil - after countless hours combing the web the only one I believe has any merit for longevity is Nikasil. The other solutions I would consider "patches", if they even work... as you've pointed out.

I am concerned that after the rebuild I will see the same soot, but I seriously doubt I will at this point. I have pretty much convinced myself the oil fouling in bank 1 has to be through the rings despite the consistent leak down (8%) and low compression numbers (150) for all cylinders.

During the rebuild I will give the potentially problematic bank 1 head a good once over, including perhaps sending it off to someone or bringing it back to the original shop that did the valve job.

Mr. Navarro's shop offered to measure bore and taper prior to the rework should I decide to send the case halves to him, which would give me further confidence in my diagnosis of failed ring seal should he find ovality or wear beyond acceptable limits for the stock pistons and rings.

Many thanks again !!!

Flat6 Innovations

If the engine is assembled correctly and ALL DIRECTIVES concerning the cylinders are followed as well as piston and ring prep you will have no issues. Also only use the proper break in oil and procedure NOT SYNTHETIC!

Do that, then send us the heads for updating and go back together with it. Apply all the updates that you can afford and do not cut any corners as they are the road to hell.



Nikisil is expensive as hell, but Porsche used it for 40 damn years with flawless results. I have utilized it for the past 14 years and have NEVER assembled a reconstructed M96 engine without it (and I refuse to). All the other patch ups are band aids that are focused on a budget thats fine for a Honda, but not a Porsche. The fastest way to loose 5,000.00 is by trying to save just one~

jsoderbe

Hi,

it would be very interesting to hear Jake´s opinion on the compression numbers in comparison to the sooting issue.

Logray, is there any way to remove the AOS tube going into the sooting bank intake? Just to eliminate any problems with that? Is there any other breather lines or similar going to that intake?


Johan

dcdrechsel

page 71

logray

Thanks Dave, interesting read that basically with the clearances they achieve with Lokasil and ring size that any ovality basically is a detriment to ring seal.

Here's what I've compiled thus far from various sources and experience regarding procedures.

I plan to clean meticiously (and then some more cleaning) and then apply LNE/brad penn SAE 30 break in oil liberally to piston's, rings, and cylinder walls prior to installation. I see F6I website also has assembly lube for sale, which I will probably buy, but my undestanding is that stuff is meant more for main/rod/cam bearings etc. but not the pistons or cylinder walls. The ring gaps will be aligned according to the work shop manual.

I have several good reads on proper break in to achieve good ring seating, but I'm all ears if there is something special required for Nikasil.

http://www.mototuneusa.com/break_in_secrets.htm
http://www.ntnoa.org/enginebreakin.htm

In summary, what I undesrtand is warm it up and then go though many successively higher 2nd gear RPM runs (example 40% to 60% of max rpm several times, 40% to 80% several times, then 40% to 100% several times) eventually working up to near red line let the engine brake each time. I read where Mr. Navarro ran his rebuilt F6I boxster like 50 times on the dyno using similar procedures. I don't have a dyno obviously, so I'm going to have to find a safe place to do this. Fortunately it should be closer to winter by the time this happens so it will help to keep the engine from getting too hot during these procedures. From there after cooling down to ambient temp, driving the car hard without lugging, while varying rpm's and speeds following similar procedures to break in as above for about 200 miles.

The break in oil changed and mag drain plug cleaned after about 200 miles. Followed by a change to synthetic. I may go with brad penn 20w50 like Mr. Navarro runs which is probably superior, but I am thinking perhaps Syntec 10w40 as a compromise, since the car occassionally sees 30 degree F startups. After another 750 miles and some more break in style driving another oil change. Then I will continue to flog the hell out of the engine like I always do. Maybe that explains why it's rebuild time for low compression at only 75k?

About the only part I'm a little foggy on is split overlap. I've read several write-ups about the subject, including this link http://www.angelfire.com/realm2/autotips/camdegree.html, however I'm not quite sure how I can apply it yet in practice to the M96. Perhaps it will become more clear once I have the engine on the stand and can visualize it. That being said, after the valve job, after I reassembled I acheived 0 degree camshaft deviation and also used a dial indicator to find true TDC. I've also invested in cam timing tools as well as wrist pin tools, etc.

I sure wish this rebuild could wait until spring time and I could afford to go to your class. Or at the very least buy your M96 DVD, but I don't think it is ready yet according to the F6I website.

For certain if I do this the crankshaft & rods are going to you for Magnaflux, inspection, and intermediate balance. I might also send in the camshafts for magnaflux and inspection as well, and possibly have them reground and coated with PC11. I might farm the camshaft magnaflux to a local shop, but they certainly don't have an M96 crank balancing rig .

Although I would like to, I doubt I would be sending you the heads. I'm installing a new variocam actuator in bank 1 when I have it out. The chains, pads, and lifters were already replaced. Possibly the #1 head would get sent to you, but only if there is a hint of a problem and the local shop that did the work can't repair it (I've already dumped $500 into the heads on the valve job a few hundred miles ago). There is a tiny amount of sooting in bank 2, cylinder 4 - and I suspect ring seal there as well even though the soot isn't fouling the plugs or making it to the tailpipe - but have no reason to suspect the recent valve job was done incorrectly at this point.

I've thought about doing this, however not being 100% sure on the design I'm not certain this is possible without removing the AOS completely. The intake hose from the AOS goes to just behind the throttle body, so it would affect (dump oil into) both banks, not just one bank of cylinders. Also I am not seeing any of smoke from the exhaust or excessive oil in the intake. Also did you see the crankcase vaccum test earlier that I posted (the slack tube manometer video)? Crank case vacuum is normal. If the AOS was bad and dumping oil into the intake that would have showed up in the test due to excessive crank case vacuum.

The AOS is brand new, the tube is relatively oil free (just a normal amount of residue). There is also the secondary air intake system that injects air directly into the exhaust manifold, however that was overhauled during the rebuild. I'm not aware of any other breather lines aside from the AOS tube to the throttle body.

logray

Sooting showed up immediately (perhaps just a few miles it was detectable, after about 50 miles I pulled the headers and saw heavy black soot coating the exhaust ports, whereas they were shiny clean after the bead blasting from valve job). Whereas after 50 miles and again at 100 miles I could still see shiny brass guides on pulling the bank 2 header. Soot was present before the valve job. The blue smoke out the tailpipe at startup and at heavy loads is gone after valve job. Soot still there.

Yes this bothers the crap out of me too. Which is why I'll probably have to take a closer look at the head. Checking valve seat seal using solvent, but also probably sending it back to the shop for another pressure and vacuum test. I am wondering though if problems in the head (5 totally shot guides, bad exhaust leak, and gaping hole in AOS boot to head #1) could have worsened or created a problem with ring seal in that bank, possibly by drawing in more unfiltered air (dirt and dust) into that bank? Also, perhaps the compression numbers and leak down results are misleading us, since it sounds like the properties of Lokasil and the behavior of the M96 might not follow conventional reasoning. Also perhaps the comp numbers were lower but are actually helped out a little now by the increased soot, maybe providing a better seal in bank 1? :-;

The only other thing on the back of my mind is on the exhaust side, all of the exhaust ports share the same SAI system and channeling, I wonder if somehow oil is in the SAI system and is being dumped into the SAI channels on the exhaust ports (which would go into all three banks). I'm up for ideas if anyone has any as to how oil would be dumping into the secondary air system. Or perhaps the oil or exhaust contamination is somehow making it's way from one cylinder to another. It's a crazy thought, and I can't reason why this would be happening. I'm all ears though.

I will certainly measure against each other or have the camshafts measured for wear, although my untrained eye didn't show any cause for alarm. I have pics of the cam journals and bearings in the rebuild part 1 thread, all the journals looked like this.



This was the worst cam bearing.



Yes this is troublesome as well, why all three cylinders in the same bank exhibit the same oil fouling on the plugs, with tons of black oily soot in all three of the exhaust ports. Although a slight clarification on earlier posts, that I do detect a very small amount of sooting in #4, but very very minor compared with what's going on in #1, #2, and #3. No sooting whatsoever in #5 or #6. #2 appears to have the heaviest sooting.

They did not replace the valves, They did replace the stem seals. Maybe I got bad stem seals? Of course they also swapped them in bank 2 as well and I would think if the seals were bad it should show up in the other head.

But maybe it would be in my best interest to have someone do a second valve job on the #1 head and replace the valves and springs. If it was a cracked valve that should have shown up in the pressure or vacuum tests? They measured the valve stem diameter between the top of the stem and the part that runs through the guides and apparently there was negligible wear. I might take them back and have a word with them about this measurement though, because after thinking about it, why would there be 5 valve guides with immense play (able to rock valve back and forth), but negligible stem wear. Yes I understand the guides are brass and soft, but I would think there would be some wear.

Smoke is GONE after the valve job. Soot is still there, enough to make the tailpipe pretty much black after 500 miles.

jsoderbe

Hi Logray, any updates on this?

Johan