Engine Rebuild Part 2

If any of you have been following my rebuild project, unfortunately my valve job gamble didn't pay off... well not as well as I hoped. While the engine is running really well after just 500 miles since the top end rebuild, I need to address a problem in all of bank 1 (right tailpipe) with oil rapidly forming on plugs and oily soot building up rapidly in bank 1's exhaust ports (but completely absent from bank 2's left tailpipe !?!?!?!), lower than "normal" compression numbers, and leak down past the rings. I am working to validate these numbers in a couple weeks when I re-test: Leakdown (through oil filler tube). [bank 1] 1 = 23%, 2 = 24%, 3 = 24% [bank 2] 4 = 25%, 5 = 25%, 6 = 26% edit: (revised leak down test with better tools reveals only 7%, but low compression still indicates worn rings) Compression. [bank 1] 1 = 155, 2 = 154, 3 = 150, [bank 2] 4 = 149, 5 = 149, 6 = 149 Assuming those numbers hold true, I'm weighing my options here and could use some help deciding how to move forward. Option 1.) Drive the car until it starts puking oil out the exhaust. Forget about the soot until it becomes an even more costly problem down the road (more damaged internals, 02 sensors, cat converters, another valve job, etc). Option 2.) Remove the heads again and measure bore/taper. If the bores and pistons are within spec, continue the tear down and replace crank & rod bearings, thrust washers, piston rings, chains, guide rails, and other hardware inside the short block. Perhaps another $1-2K for DIY on top of what I've already dropped in to the engine ($3500). I could probably manage this financially. Option 3.) Walk away from the car and take the 15-20k I might get for it to find another 911. I really love the car though and can't see myself doing this. The following two options mean I'll have to start parting with beloved possessions such as EVOMS intake, carbon fiber steering wheel, carbon fiber shift ****, PST2, roof transport system, !8" Sport Techno Wheels with new Bridgestone RE050A's, Escort Passport 8500 x50 radar detector, etc. etc. Option 4.) If one or more bores is too oval or worn, send the block off to LN engineering for 3.6L rebore and JE pistons. This would bring my total spend up into the $8500 range. Option 5.) Sell the M96-01 complete engine, and pickup a reman LS V8 crate engine, then put the money of proceeds of sold items towards the conversion instead of the M96-01.

Don't get too caught up in the little things. Does it run? Well? Pulls strong...drive nice? Then just drive it and enjoy it. It's way too easy to get caught up in the minor stuff, but you could spend your whole life trying to fix/make right every little thing and never get it done. It's an old car, it's never going to run like brand new no matter how much money you put into it. Now if only I could take my own advice, I'd be a happier owner myself sean

Logray - Seems strange that the problem is in bank 1 with the numbers you give. The leakdown on that side is lower and the compression is higher. I would expect the opposite if the piston rings were a problem. You had the valve seals replaced on both sides right? Could you have a bad head gasket? If you are going to put in the new actuator I sent you you could pull off this head again, Of course you would have to go for new head bolts and head gasket to do this. A bad AOS would be putting oil into both sides. Except for the problem with the actuator I would agree to drive it for a while.

Did you split the case at all? if so what was done with the cylinders and rings? Did you look closely at the valve guides in the heads? These are known for wear in the 3.4 engines. How about stem seals? Both these issues will create chamber contamination. With that low of compression and huge leak down all going past the rings 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. Been there and done that and its no fun at all. 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. If you really do love the car, do this once and be done with it. If you don't go all the way you'll be throwing good money at bad over and over and over again.

Oh no!!!! its never good when theres a part 2...... part 1 was enough. I am not sure I understand your compression and leak down results. Is "bank 1" cylinders 1-3 or cylinders 4-6? I cant see all 6 cylinders being a problem and your compression is evenly low on all 6 cylinders..... I am pretty sure the correct compression for this engine should be in the range of 180-190psi and leak down 3-5% maybe a little more. I forget exactly what you did in part1 but I remember head work being involved.... Did a reputable shop do the head work?? if not, I think I would bite the bullet and have the heads sent out to a proper shop or at the very least, find a good use head and try that on the problem bank. See if that improves your compression and leak down #'s . Valve problems can really mess with a engine.

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. It does seem like there is a missing link here somewhere, knowing what I do about these cylinder heads also raises my eyebrow a bit as well. Like every part of this engine they have some inherent characteristics that must be adhered to during any sort of intervention.

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Yeah definatley don't want to understate this problem... after 500 miles the amount of oil fouled plugs and soot accumulation I'm seeing is pretty alarming. My guess is since the valve job was done now the cylinders are sealing up better and the problem with the rings has become even worse or "more apparent". This is the dilema of what I'm struggling with too, maybe unless someone forgot to install the piston oil rings in bank 1? What I am guessing is that for some reason there was a problem in bank 1 that went on for a long time that also affected the ovality of the cylinders in that bank and therefore perhaps greater ring, piston, or cylinder wear causing more oil to seep through. I know there was an exhuast leak in cylinder #2, and there were 5 valve guides that the shop replaced in that same head. What is also troublesome here is that after 500 miles the engine only consumed about 1/4 of a quart of oil, probably less. Before the valve job the car was in the 1 quart per 1000 miles club and quickly worsening. Yes the shop installed all brand new valve stem seals. No, I did not split the case. And I examined the cylinders for scoring and visible wear and could not find any. I did not measure the cylinders for bore and taper. The shop measured all of the valve guides. 5 of them were replaced due to being out of tolerance. The valve stem seals were all replaced with brand new (both heads). This is my vote as well, but I want to send this out to the community to get some second opinions. Thank you for the sound advice as always. Bank 1 is cylinders 1-3 on the drivers side. This is what is troubling me as well that the oil seepage is only on bank 1. Bank 2 is still "clean". I have thought about this, however after the leak down test, I am pretty confident the air was only leaking past the rings and audible through the oil filler neck. I could not hear any air leaking past the intake or exhaust sides. I also tried advancing cam timing to +6 degrees, thinking that perhaps for some reason the cam timing was too retarded and causing more oil consumption. In the end, the car runs the smoothest and has the most power when cam timing is 0 degrees. Pulled the exhaust header on bank 2 and do not see oil or soot present. The oil rings have certainly completely lost it on bank 1. I am pretty sure this is the case, because the soot and heavy oil consumption was present (all in bank 1) prior to heads being removed for a valve job. I gambled that the problem was with valve guides. When the shop found 5 guides that were totally gone (and one guide in #2 ex where could literally wag the valve back and forth in), I was overly optimistic that there was the source of problem. While the valve job did curb the smoke and oil consumption dramatically, I should have been more scientific about cylinder measurement and gone further to crack the case, but my pocket book was burning at that point. I am thinking the damage might have been started with 1) a very bad leak (large gaping hole really) in the AOS bellows and 2.) a very bad exhaust leak in bank 1, caused by a bowed exhaust header. If I do decide to pull the heads again, I might bring them back to the shop. They did vacuum and pressure test and said they sealed up properly after the work.

I forgot to mention the intake vacuum gauge readings point towards worn rings as well... of course I'm not familiar if this is a tool you can rely on with the M96-01 (perhaps because of variocam?). The quick throttle openings to 2500-3000 rpm cause it vacuum to go to 0, then after the flap is closed only back up to 19/20 in Hg (instead of 24+ "normal"). And at hot idle, only 15 in Hg and steady (instead of 17-21 for "normal"). http://www.youtube.com/watch?v=0zBGhJCHTyw

Logray, For what it is worth my answer is.... if you can swing it. http://cgi.ebay.com/ebaymotors/Porsc...item2313f4c582 Woops noticed it was Motormeister not sure there reviews where great but at least it is an alternative. Yours sounds pretty good for such low compression.

Do as Jake says... ...if that is within your budget.

Logray, are the oil extractionpumps at right position? I mean the ones in cyl. heads. If the oil level in heads are too high, it could cause these symptoms?

Difficult decision .Assuming the worst and that cylinders need to be resleeved -looks like there are several options -LNE at $4,000 with pistons ,rings and wrist pins + rebushing connecting rods .I guess cast sleeves also an option -LA Sleeve was quoting $1,500 some time back -potentially could reuse old pistons with new ceramic coating .Problem is pistons rings cost almost as much as new pistons with rings and pins .Which makes new pistons the viable solution .I am guessing $150 a hole .It woulkd be helpful to know how the factory treats cylinders when they rebuild -do they sleeve or rebore ? The other major expense is the crankshaft -magnufluxing and balancing recopricating mass -don't know the going rate . I would guess that all in it's a 6,000 to 7,000 project which would yield a very good -reliable engine .

SpeedrII, thanks it's a thought, but the oil extraction pumps (both new) are installed correctly. I've also had them off and back on to alter timing a few times. Also i don't think the pumps would explain why there is soot in cylinders 1-3 but not 4-6. Oil level is one bar above half way mark on the dip stick. dcdrechesel - I haven't looked into crank balance yet, or if that is something I could safely skip and revisit during the 150,000 mile rebuild. Edit: I also forgot about injectors (thanks Greg)... mine are the older blue style. They were professionally cleaned and tested along with the valve job. I'm wondering if I would have to go for the newer light green injectors with improved spray pattern (or another p/n) if I go with the 3.6L upgrade. I've read about heat and other issues with cast iron sleeves. I would consider that a patch versus LNE solution. And as you mention, add in pistons, etc - the LNE option makes the most sense and is the only one I am considering if I decide to rebuild what I've got. Here's a couple reads on cast iron versus Nikasil. http://www.911uk.com/viewtopic.php?p=633086 "For example some are now fitting iron liners as a solution. The problem is caused by too high cylinder wall temperatures - and iron liners not only need more clearance but will run hotter wall temperatures (and the ring material is not ideal for iron). The original piston coating seems to last at least 20K more often 60K - but no one knows how long it will last in iron (for a while for sure). Iron liners would be by far the cheapest solution yet all similar performance car manufacturers have gone away from it for good technical reasons and it seems a backward step to return." -Hartech. (Interesting side note that Hartech also claims to be able to overbore Lokasil without resleeving!) https://rennlist.com/forums/996-foru...000-miles.html "members of the industry who are repairing just one sleeve when they make block repairs, the factory also does this as mentioned in the quote above. Generally a ductile iron sleeve is used by the other companies to fix just one bore or individual bores, which generally makes no sense to me, especially considering the differentials in ring capability with the ductile iron Vs. lokisil in the same engine. Lots of these are not working out very well due to the differentials in expansion between the ductile iron sleeve and the parent material, but it is a cheap way to patch up a block for further use. We never do this, LN will not do this even if you request it" - Jake Raby

The lack of porsche published specifications/tolerances makes it really tough to make an informed decision .No suprise that Hartech is overboring -the factory has to finish bore the cylinders .That could be a root cause .Even if you pull the heads and check for taper -what is ok and not ok ?Porsche offers several piston sizes but only one ring package (assuming my research is right )which suggests there is room to manuver and that reboring could be an option if Hartech would share the tolerances .

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I have been writing the book on this for the past two years. Literally. Hartech does it one way, LN and I do it another. Both work better than factory.

There is a real need for the book .I would like to buy it-soon . Dave

On a conventional motor, I'd say ring seal is OK and your compression is as well. I'd question your gauge and method of taking the readings. Your maximum differential is 4% or less and that is in the range of a very good performing motor. Generally ring seal will not deteriorate uniformly like this. If things are getting oiled up on a couple of cylinders, I'd suspect vg seals first on a conventional motor. I've never been inside an M96, so as pointed out in earlier posts, things are different with them. If power is good and drivability is fine, I'd keep going and play things out a week at a time. A hotter plug might work on the cylinders that are oiling. The motor most likely won't get better, but it may not get worse either. After rereading your post, I'm questioning your leakdown numbers. Average 25% leakdown on all cylinders, and the car runs really well? Low compression too, and it blows oil only on one bank? Any possibility the AO seperator is askew, or it's an external problem pusing oil in the intake? Does the car seem to pull has hard as before? I'd think the large leakdown and low compression numbers would make the car feel pretty underpowered. No expert with the M96, but some things to think about. GL!

dcdrechesel. Regarding bore/taper measurement: "As there aren't any published specs for the lokasil bore that I am aware of, I'd say anything over .002" ovality is too much. Most of the blocks we get here for re-working have at least that much and upwards of .005-.006". The bores are finished straight and that's how we do them. We did tests years ago and found that trying to use torque plates and simulate actual engine parameters was a crap shoot. You get the best results with a bore as round as possible within .0005". " - Charles Navarro From https://rennlist.com/forums/996-foru...000-miles.html I'm pretty sure after 75k miles, fitting new rings without re-boring is going to be a band aid (if the rings will even seal). And then after what I've read and understand about the 3.4L cylinders it is only a matter of time before they oval. Although If I do end up pulling them and the bores are still within tolerance, I will do a backflip and marry my dog. Only then perhaps might the topic come up of replacing just rings and perhaps a piston or two. Of course, who has the specs for pistons? Porsche does but isn't telling us - your guess is as good as mine what tolerance range x is: "99610305118 piston tolerance range X" Damn you Ferdinand! edit: actually they do give us weights in grams... 996 103 051 18 piston tolerance range X -01 6 number plate - 544 -547 G 996 103 051 19 piston tolerance range X -01 6 number plate + 547 -550 G

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I am going to redo the numbers in a couple weeks as I also suspect something is strange considering the symptoms. I would have expected different results based on what the visual keys are giving me. My compression gauge is old and my leak down tester is cheap. I am going to invest in some better tools in a couple weeks and repeat the test. I'd rather have reliable results to base my decision on, if I'm going to drop another $5 grand or more on the engine. Well seeing as how the car is on it's third AOS, this latest one was brand new from Porsche, fitted while the engine was removed, and all of the hoses and tubes replaced. Also the problem with the soot was present before the valve job. When I pulled the heads both intakes had the same amount of oil residue on them. And recently I tested crank case vacuum with a slack tube manometer and it was steady at 5 inches of water drawn indicating normal vacuum. It pulls much harder than before the valve job, but not nearly as hard as it once did.

Wondering about the quality of the valve job. I've seen shops use a Serdi cutter improperly and actually make a worn valve to seat seal worse after their job. Seen machine shops do poor work as well. Has nothing to do with the overall reputation either. One tech that doesn't understand fully what he's doing and the job quality will suffer. Some valve jobs I've done with Nuway cutters on 24 valve Superbike motors would take days to get right where I was happy with the seal, the contact relationship of valve and seat. Was valve to guide clearance checked before and seal at valve to seat interface after the job?

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The valve to guide clearance was checked on all guides before the work. I have the numbers somewhere written down. 5 of the guides in the bank 1 head were so far out of tolerance they were replaced. I'm not aware of the valve to seat being checked... they were pressure / vacuum tested after the job and were found to be good from what I was told. If I do pull the heads again, perhaps I'll take them back to the shop.

logray, just do what I did, stop worrying so much My car stil makes (sometimes) that od starting noise, but who cares. Just drive it, and when/if the time comes, build new engine for it. Or trade it to 997

Thanks speed rII. Trust me I'm enjoying the car and driving it just as hard as I used to. I've invested a lot of time and money into it recently and I don't want to see all that good hard work and money go to waste. Certainly I've got some time to think about this and keep driving the car, because the oil and soot is not going to cause an immediate problem. Also as to nick's question, here is what the shop gave me. These are all after measurements: intake all between: .0012 and .0020 exhaust all between: .0015 and .0025 stem height: 1.695 to 1.702 valve stem diameter: "negligible wear" new valve seat angle: 30 - 60 - 45 vacuum/pressure test: good new customer provided valve seals installed I also personally watched them take some of the measurements. One of the exhaust guides below #2 cylinder was so bad, we put a valve in and could wiggle it around quite a bit.

Your specs look ok. A good fail safe way to check the valve face to seat seal is to fill the port with solvent above the valve level, then direct a stream of compressed air around the valve perimeters on the combustion chamber side. Any small bubbles on the port side will indicate leakage. Sometimes (rarely) any very minute leakage may improve as the valves peen the seat surface. This could depend on the hardness of the seats and valve face material and the method of cutting or grinding the seats. Personally, I like zero leakage and will work at it until I get a 100% seal.

Thanks nick49 and everyone for the input and suggestions !!!

Had time to do another leakdown and compression test after some new tools arrived. Just as a tip for anyone considering buying a Harbor Freight leak down tester. DON'T DO IT . Engine up to operating temp, all spark plugs removed, fuel pump disabled, oil filler cap removed, throttle flap all the way open. Engine rotated to TDC for each cylinder being tested. Survey says!!! leak down (air through filler cap) 1 - 7.5%, 2 - 7.3%, 3 - 7.6%, 4 - 7.4%, 5 - 7.4%, 6 - 7.4% compression 1 - 150, 2 - 150, 3 - 149, 4 - 149, 5 - 150, 6 - 149 I'm pretty confident in the leak down numbers at this point, performed at 100psi and with a $100 tool. As for the compression, I suspected my old gauge was bad so I also sourced another one. UNfortunatley I got exactly the same numbers with the new gauge. Since I didn't have a baseline on a rebuild engine with either gauge I tested the 8 year old Dodge and saw numbers in the 180's. I didn't bother oiling the cylinders to see if the numbers went up. Yes the piston rings are worn, yes they are sucking oil into the combustion chamber, and yes it is rapidly coating the spark plugs with oil as well as the entire exhaust system below it including the O2 sensors. I suppose it is even possible the professional valve job did not attain 100% valve seal despite their post-job pressure/vacuum testing, which I will most certainly test if I do pull the heads again (thanks nick's tip which I also recall seeing on wheeler dealers using gasoline). But I doubt it, considering the leakdown test did not detect any leakage past the valves. With such even wear I am considering gambling again even after reading ad-nausea about the shortcomings of lokasil, the thin walls, and ovality on high mileage engines. The gamble would be not touching the cylinders and just replacing the rings, and of course bearings, and other case/bearing carrier cracking while you're in there items. I guess I would have a good idea if this might work if I measure the cylinders wear. Then of course since they will probably be out of tolerance, I would have an engine all in pieces knowing I don't want to spend $10,000 on a car that's not worth even twice that. This sucks. Really really sucks. I ran the numbers and an LNE 3.4->3.6 rebuild done the right way including crankshaft balancing, magnaflux, JE pistons, Nickies, and all new gaskets and ARP hardware will run me $7000 . That's assuming I don't find any major problems on tear down (rods/shafts ok). That's on top of the $3500 I've already spent on the heads and other ancillaries ($1500 of which was recouped). So the total spend would be about $10,000. On a car that might be worth $18-20k ????? Ludicrous !!!!!! Of course, possibly the car would be worth less given those low compression numbers. I could just do rings for about another $2000. I could ignore it for free. I could buy a used engine for around $5000 and gamble even more. It's a shame the car is running so well. It is hard to ignore the soot spewing out of the right tail pipe from bank 1. Does anyone have a used 1999-2001 3.4L engine for sale? LOL. Anyone have a good short block for sale?

3.4 complete or short block motors in rebuildable condition are far & few these days and getting quite expensive. My advise would be to yank it apart and do the bottom end before it implodes leaving you with a un-rebuildable core. You're halfway there already, finish it....

Not so sure reringing without some cylinder treatment is an option .Something has caused the rings to degredate.It would seem logical that if Hartech can bore these blocks someone in the states should be able to do it .Of course that leaves the pistons and rings sourcing issue to be sorted out .Hartech might be a option there .

I don't think replacing the rings makes much sense. If they cylinder is out of round and the rings are worn it's probably where the diameter of the cylinder has been reduced. That means your blowby is occurring where the gap between the cylinder and the ring has expanded. Putting new rings that still don't mate with the enlarged diameter wouldn't seem like a meaningful solution. -Shawn

spend the 7k and enjoy the car for another 10 years.

I just missed out on a local 2003 C4 911 that was parted out due to a accident..... they sold the 3.6L engine for $3500 in perfect running condition. I would have bought it for a spare. They still have the C4 6speed transmission available..... there asking $1500. I was thinking it would be a good spare at that price. I again find it very hard to believe all 6 cylinders/rings are faulty. Maybe try a few oil changes with some straight BREAK IN oil. It might help your rings get a better seal. Again, its a long shout but you never know..... http://royalpurple.com/breakin-oil.html

I dont remember if you removed the pistons from the cylinders.... If you did, maybe the rings are possibly worn to cylinders that are not quite oval and the rings possibly rotated. If you keep driving it the rings could possibly wear and achieve a better seal . I would give that break in oil a shot, do a full flush of the current oil . Again, its a long shot but..... You may have already read up on the "break in " topic but if not http://www.ntnoa.org/enginebreakin.htm

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Thanks again everyone for the input. Yes I'm pretty aware that re-ringing without cylinder treatment is not the smart thing to do. And I normally don't do things that aren't done smartly. I guess I was just venting. All 6 cylinder ring seals are not faulty. Those in bank 1, cylinders 1-3 are most certainly faulty - in various stages of disfunction, perhaps #2 being the worst. In bank 2, cylinder 4 has some evidence of ring seal loss and very minute amounts of oil burnoff/soot (tiny compared to 1-3), whereas cylinders 5 and 6 do not show any evidence of ring seal loss. After reading the break-in link you provided I'm not sure a 75,000 mile engine could achieve break in or better ring seal. It sounds like once the glazing happens, the only solution is to re-hone and re-ring. There's bound to be wear that no oil is going to help at 75,000 miles. I'm not much of a fan of mystery fluids, but certainly break in oil sounds more logical than slick 50, . Perhaps it might be worth a few compression points? All kidding aside I will certainly be using 30 wt. break in oil per F6I/LNE recommendations if I do the rebuild. No, I did not open the engine case. Only the heads were removed. ... Anyways, I think my head is dug out of the ground at this point and even though the poll in this thread says to keep driving it, the other half of me is really starting to look forward to a 3.4 -> 3.6 L upgrade. I just hope I won't regret this decision. Spending $10k on a $20k car. Of course it will be substantially upgraded when I'm finished. I'm sure I won't be regretting it when I'm smoking other newer 3.6L 996's out there in my 1999 car. When I pulled out compression tester on the 8 year old Dodge and saw numbers in the high 180's, it really gave me some ammo for the rebuild. What I've read is very consistent with ring wear. Good static motion leak down test numbers (7%), but poor compression numbers (moving test) = bad ring seal. That coupled with the recent valve job, knowledge about the cylinder ovality issue, and vacuum gauge readings leads me only to once place. Backwards spending $10,000 on a $20,000 car Crazy land. : bowdown: :bigbye :

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Logray, at least you are not spending 3k usd and be right at the starting point I hate to put my engine back to my car with out the mods that I was planning to in future. I think that I must start building engines to other people again... Just to finance my 996 hobby

True that speedr2... I'm going to find the money somewhere... and I think I know where!

If you haven't already read it, I'd dig through Hartech's website and buyers guide. They claim they have a method for returning cylinders back to circular without sleeving. According to their guide it's an application of heat and pressure in two directions to reshape the cylinder. They then machine the casing outside the liner and fit a restraining ring to prevent future "ovaling". I have no idea what this costs or how effective it is, but it seems like it might be worth looking into. -Shawn

Thanks Shawn, yeah I did read about their methods and they are interesting. They claim to be able to overbore Lokasil and put in new pistons w/rings that are weight matched. And while it is a solution (patch) the finances for it don't seem to make sense from the USA as I'm not aware of anyone in the world except them that does that type of work and has that kind of expertise. Shipping the cases alone to the UK will more than make up the difference than it would just cost for me to have it done the "right way" here in the good ol' US of A.

Judging by the votes I am supposed to keep driving the car and forget about the oily soot and low compression numbers. But what fun would that be when I could have some more horses under the hood? Anyways, as insane as it may seem to spend $10,000 on a car worth $20,000 on a good day, I am about 90% certain I'm going to take the plunge for LNE's 3.6L re-bore and "finish" the engine rebuild. A lot of it depends on how much funds I can raise. Unfortunately the old girl is going to have to chip in to make this possible, as is the rest of the community. Up for sale soon are some valuable upgrades for YOUR Porsche, so I can upgrade mine. We all benefit in the end you see! Depending on how much of this stuff goes will dictate the build quality and extra goodies I can pile on. Such as... -R&R connecting rods -Level 2 crankshaft balance -LNE billet chain paddle -LNE spin on oil filter -Mr Raby's engine rebuild class or DVD Although it looks like Mr. Raby's (unfinished???) rebuild DVD might not be avilable just yet and it looks like I already missed the boat this year for his engine class. Shucks.

I keep seeing you say that you don't want to spend 10K on a 20K car. Why? Who cares what the car is "worth". Look at it this way - if you enjoy the car, and it's generally in good shape, then spend the 10K to get the engine rebuilt properly. The most expensive item on the car - any car - will be like new and will give you many more years of enjoyment. In the long run it will be less expensive than buying another car, and once again losing more money through depreciation. You won't be spending 40K on a new to you used 997, which itself will have a "used" engine. Instead, you'll spend 10K on a car that's very near the bottom of its depreciation curve and end up with a gem of an engine and a car that will give you many more years of enjoyment. Look, cars are almost always money losers in the long run (unless you're talking about a true collectible, which almost no 911 is). Since this is a given, you will lose less money in the long run by repairing this car as needed and enjoying it for as long as possible, rather than roping yourself into another 40 to 50K car every few years, only to see each of those cars lose tens of thousands of dollars of resale value by the time you decide to sell and move on each time. Enjoy the car for what it is and spend the money as needed to keep it in top shape, knowing full well that in the long run you will lose LESS money overall by doing this than by replacing the car every few years.

Hi Logray, I guess I am dumb as a nail, but I still dont get it; how can you have perfectly even leak down and compression numbers, and still be so completely sure oil gets through on just one bank? When you compare with your dodge, doesnt the relative compression matter? I would find a local rennlist member, and offer him a free leak down and compression test on his 996 3.4, just to validate your equipment and your numbers. Basically I have understood these engines to be two separate engines, that is joined through the cam timing. That mean they could act different, and need to be treated differently. I cant recall if you have done any exhaust analysus? Have you ruled out that the sooting is fuel? Have you interchanged the Injectors? Can you switch the harness to the injectors to the other bank? Looking at the numbers you present, at least I would never connect that to your major symptom, the sooting in one bank. Could your problem be that one bank is way too lean? I am just saying, make sure you find the problem BEFORE you dump 10 grand into it! Worst case is that you dump the money into it just to see it sooting again after 500 miles. If you dont find the actual problem, I would go for a 5 k used engine, and sell your restored heads to me....:-) Regards, Johan Johan

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Thanks for the words of advice, I'm already over it. The car will be mine forever since I'm 95% positive I'm going to do the rebuild. It's still quite an investment though. Hey I guess people pick up old cars all the time and pour money into them for restoration. Perhaps my 996 will be one of the only one left running on the road in 10 years because it's engine will be rock solid. I suppose my hesitation was whether it would be smart to ditch the car and use the money to get into a newer model. But like you said that car is also going to have a used engine and it's own fair share of issues, etc... I'm actually more of a new car type of person, but when I sat in my 996 4 years ago, it was a pretty magical moment, this is part of my decision for doing the rebuild. Actually a correction, oil is also getting through the rings on bank 2 in cylinder 4, but nowhere near to the degree as bank 1. Here is my evidence for ring seal loss, hopefully someone can validate this info as the correct diagnosis which I've compiled. If there are any other tests I can do sans tearing the engine apart (which may happen regardless), please let me know! 1.) Low compression numbers but good leak down numbers. Even though compression is consistent, it should be much higher than this. I believe the theory goes: if you have good leak down numbers coupled with the low compression it means the rings are shot. Compression is a moving test, so as the rings move with the piston any imprefections, wear, ovality, cylinder wall damage will show up in the compression test, but not the leak down test - because that is static. When performing the leak down test all of the leakage was through the crank case. With the oil filler tube opened, all of the air from the cylinders was leaking past the rings. I could not detect any leakage through the intake or exhaust. Also the poor compression numbers were validated as being very poor by Jake earlier in this post. About three years ago @ 40k miles using the same compression tester on the same engine I was seeing numbers in the 180's. But I too am a little curious why would I see similar compression numbers, but different amounts of oil leaking past different cylinders. By visual inspection, in some cases, no apparent contamination, and in others plenty of soot. Perhaps the rings were never seated properly and the engine was not borken in as it should have been (I am the third owner). Or perhaps the engine was rebuilt at some point and the rings in bank 2 were replaced. I don't have a complete history from the PO. 2.) Low vacuum gauge readings. I've had a mechanic who works on 996's tell me the intake vacuum gauge readings should be above 18 inHG and between 18 and 22 inHG at idle for normal. Mine are barely 15 at idle. When blipping the throttle, the vacuum readings do not go above about 19/20. When they should go to 23-25 on a healthy engine. On my Ford, I see exactly this: 18 at idle, blipping to 25. So I know the gauges is working (yes it is not a comparative test though, I agree). The combination of the low gauge readings coupled with the low throttle blip reading indicates worn rings. You Tube 3.) Recent valve job. Many new valve guides, new valve stem seals, 3-way cuts, and vacuum/pressure test say that I shouldn't be having a problem with the heads at this point. This was partially confirmed by the leak down test. Before I spend all that money though and send the case halves off to LNE, I will certainly pull the heads first and do the solvent test to see if there is any leakage through the valves. If there is any evidence of a prolbem they will go right back to the shop. In fact I might bring the #1 head back to them anyways just to get their opinion on the data I've got. The valve job indicated there were problems in bank 1 such as several very bad guides and an exhaust header leak, so I am wondering if those problems could have perhaps accelerated or casued the increased ring wear or perhaps leakage/contamination problem. Those problems were not present in head #2, and there's not any soot there either (or at least a very very small amount in #4, not enough to make it all the way to the tail pipe). Still though, after the head work and valve job, if the source of the problem was with the head I should think it would have been resovled. So perhaps the damage was already done (rings) or there was an unrelated problem at the same time (rings or cylinder ovality). 4.) Presence of oil on spark plugs. The plugs, just after 500 miles (now 650) after the valve job are coated in what looks to be oil fouling. All of bank 1 plugs look like this. All of bank 2 plugs look like this. 5.) Presence of soot in the exhaust header and exhaust ports. Pulling the header reveals a lot of this soot - basically everything is coated in black, where it was basically clean upon installation, it looks like it's seen 50k more miles. If this were a diesel I wouldn't be concerned. Comparatively, bank 2's exhaust ports, plugs, and header is still relatively clean. Although I did detect a very small amount of soot in #4/bank 2. Certainly, carbon is a fact of life for any engine, but the soot, and non-scientifically leaves an oily residue when wiped with my finger, indicates contamination. At this point based on the above info I am very confident it is ring seal loss. What else could it be??? Of course there are still many many other reasons for sooting. Yes is absolutely does and you are 100% correct, this was more a sanity check to make sure the gauge was not stuck or something. It would be smart of me to do this. I pondered that perhaps the cam timing could be too retarded, which could explain excessive oil consumption and sooting. I experimented with -6 degrees retarded, 0 degrees, and 6 degrees advanced. In the end of that test, the soot accumulated just as quickly in the tailpipe for bank 1 on all three cases. Within just a few short miles, the soot was back after cleaning the pipe. And in the end the engine runs the smoothest and has the most "butt dyno" power at 0 degrees camshaft deviation. I have considered this and am not sure if I've ruled this out 100% yet. Perhaps I should also test for volume and pressure. I'm not sure how else to test this aside from taking Durametric readings related to fuel delivery. I had the injectors sent out to be cleaned and tested and they came back to me tested 100% and were reinstalled back in the engine in a random order. Here is the fuel injector report: http://img851.imageshack.us/img851/3015/drinjector.jpg The numbers provided from Durametric say everything is in spec: FRA at 1.04 for both banks and TRA at -0.16 for both banks. Additionally I replaced all of the oxygen sensors during the valve job rebuild. Same soot before/after rebuild. Do you still feel the same way now after the above information? Are you thinking the oil contamination would be coming from the valve guides even though they were all measured and bad ones replaced, then valve stem seals replaced with brand new and the valves cut 3 ways, along with a good pressure/vacuum test? Or are you saying the AOS is dumping oil down the intake? Maybe the spark plugs aren't hot enough? This is also the third new AOS on the car, and the intake risers looked identical between the two banks when I last had them out. The brand new AOS appears to be fine BTW, I tested it with a slack tube manometer. You Tube Both cats read 180 degrees F... You Tube

Well, I'm not the one you have to convince, it is you that have to be convinced.... I'm just saying, you should be able to drive a car with that consistent leak down and compression numbers all day long. Sure you would miss some power, but it would still be a powerful and fun car to drive. Much as your seems to be today! I would never pour 10 grand into the engine before I know what is wrong. I think the 3,6 route is the right desicion, and I think you will gain 5 k back in higher resale value. But, think of the absolute nightmare if it is still sooting after 100 hours of work and 10 k. I guess it is another learning experience for me, but isn't the O2 values way off? If you replaced the sensors, did you re-check the values afterwards? If not, have you replaced the O2 sensor wiring? Regards, Johan

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You have a good point. I'm all ears, any ideas on where the oil or fuel contamination could be coming from? MAF would affect both banks. If it was an 02 sensor, I would see it in the readings. Besides the old 02 sensors I had on before the valve job gave me the same readings and same sooting, albeit they took longer to heat up. The values are nearly spot on actually. The right two columns are supposed to fluctuate like that. I have the factory set points for 90deg C idle from the workshop manual. Ign timing is supposed to be 5.3 +/-0.7. Mine jumps a little higher than that as does rough running, possibly from a slight miss due to fouling or combustion contamination or timing is not 100% dead on, or??? Air flow is supposed to be 17 kg/hr +/- 2.5. Spot on. Short term fuel adaption FRA bank 1 is supposed to be 1.02 +/- 0.04 (mine's at 1.04 and steady) Short term fuel adaption FRA bank 2 is supposed to be 1.03 +/- 0.05 (mine's at 1.04 and steady) Long term fuel adaption TRA bank 1 & 2 is supposed to be 0.00 +/- 0.1 (mine is at -0.16 little out side of that) O2 sensor voltage is supposed to fluctuate between 0.04 and .79... Durametric can't read that fast, but it does fluctuate like it is supposed to. As for the wiring, if that were a problem I think it might show up in the sensor readings?

Ok, that explains the jumping values. But, how can you rule out a intermittent wiring problem? Would the CEL catch that? I'm not that familiar with the US terminology, but am I right when I don't see any exhaust related values in your documentation? Over here in Europe we measure the exhaust carbon oxide level (CO) and the amount of unburned oil related hydrocarbon (HC). Not sure what you measure in the US, and the terminology. A typical CO value is 0,1%, and HC is maybe 20. A worn engine show a significant increase in both, which eventually will make the car fail the mandatory vehicle inspection. My 996 showed CO 0,00 % on both banks, and a HC reading of 0 and 3 respecively, showing a very, very slim difference in the amount of unburned gasoline and/or oil from one bank. The unburned gasoline and/or oil is what create the sooting. I would anticipate that you have different values for each bank, and maybe these values might point you in the right direction? Regards, Johan

Logray, I am in San Jose and have a 2001 996 3.4 with 88k miles... willing to have testing done on my car with your tools if you want to do a comparison. David

Quotes source posts: 8895661, 8895751

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!

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

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

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

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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.

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

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?

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.

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 !!!

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~

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

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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.

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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.

Hi Logray, any updates on this? Johan

Yep, block is still at LN engineering being upgraded to 3.6L... here were the last pics of it about 4 weeks ago before it was shipped off to them. I hope to post more pics soon, and get the car back on the road in less than a month.

Ok, maybe you started a part 3 that I have missed? How did the sleeves measure? Did you find out what was wrong? Johan

The part 3 thread hasn't started yet... It might have been a little short sided of me, but I did not measure the cylinders. Since I already made the decision to have them rebored, the end result is really what I'm concerned about.

More than likely, it's a cracked cylinder head, mine was on the number 1 cylinder, the usual place. Costa Mesa R&D is doing the head repair and rebuild.

Nope, no cracks in the head. The valve job included a pressure test which yielded no cracks. Blackstone showed zero coolant in the oil. And there was no oil in the coolant. Just oil contamination in the cylinders. All the diagnosis and evidence supports worn piston rings and/or worn or oval cylinders. New cylinders, pistons, and rings are going in... As a side note, when I was removing the upper oil control rings from piston #2 a piece of the ring broke right off. I barely applied any force at all and it just cracked, the metal appeared to be very brittle. I'm wondering if it was already cracked (which could explains some of the oil fouling). edit: oh I checked valve seat seal on bank 1 head using some solvent. Not a drop leaked through, the level stayed the same for at least 5 minutes.

logray, how is your LN rebuild going? did you get your block back yet?

Hah, funny you ask! Case halves were delivered on Friday. I am still waiting for the pistons. One thing to note: LNE says that they do not clean blocks and they will come back to you as clean as you sent them in... well technically mine came back dirtier than when it was sent. You wouldn't believe the amount of metal shavings everywhere!!! In fact, you can clearly see many of them in these pics. I have a mountain of work ahead of me to clean them all out! More info coming soon!

You would think they would at least blow them off. Was their turnaround time accurate? I'm thinking of going for the 3.6 to 3.8. Do you know of anyone who has been running the larger bore/nickies? I would imagine there have been quite a few.

So the pistons did not come with the cases? Seems kind of strange to me if LNE is supplying the pistons. And I am surprised that there were metal shavings. It is one thing not to clean the cases of corrosion, etc. but another thing not to clean up the shavings from machining. That really surprises me.

Actually it looks like LNE might have farmed out this work, but I'm not totally sure on what the business relationships are, it might have been one of their "legs". The pistons/etc. come from JE and have to be ordered separately and shipped to LNE first which is why they didn't show up with the case. Yep pretty surprising to me too, but I guess they do disclaim this part well that they simply do not clean anything and that is the builders responsibility (although if you send them a case that is completely oiled over they will certainly charge you to clean it first). There were a ton of metal shavings even in the box they shipped in and all throughout the cases. After blowing them out I'm going to have to go through with a microscope to make sure every last shaving is gone. Then a good hot water mild soap scrub down, followed by denatured alcohol and chem wipes until clean.

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I think pretty much any F6I car has been Nickied, so there must be loads of them on the road. Yes the turnaround time was very accurate. 5 weeks pretty much on the dot.

So, it's up to you to check the piston to bore clearance? And the pistonring clearance? Sound's odd to me... Or the tolerances are so tight that...

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I have one 3k track miles and running great!

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Yes up to me to measure/check/correct clearances for pistons and rings. But from what I understand (read/told) the tolerances are generally correct from the manufacturer. But that won't keep me from measuring everything, installing the rings and validating their gaps are correct before final assembly.

Did I find the smoking gun? Piston cooling jet in #2 is damaged and totally clogged with a metal shard embedded. Of course, all new oil spray jets are going in (after all they are only about $6 each). Perhaps this lead to a hotter #2 (and adjacent #1 and #3) and over time oval bores and loss of ring seal? Oil fouling in #2 was the worst of 1-3. The shard came out, but underneath it's completely damaged and "welded" shut.

Any idea where that shard could came from?

Looks like a manufacturing defect to me (yep, I used to work auto manufacturing quality control).

Wow, that was unexpected! Any signs of the engine being rebuilt before you got the car, or is that a factory defect? I am not that familiar with the process, but can it be left overs from the re-sleeving? Just guessing here; I can imagine that a 50 degree piston temp difference could create all kinds of problems, from premature wear to excess carbon buildup... Things like that scares me. Talk about needle in a haystack, that is a problem that you can throw tens of thousands at without resolving it. You are very fortunate to be able to do your own work, but still there are many hours spent there. Thanks, Johan

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Would you mind expanding on your experience with your 3.8 performance and driving characteristics? I'm building one now...

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Not related to sleeving, the shard was there upon engine teardown. I don't think the engine had been apart before. I'm still waiting for pistons so I can have the engine balanced before starting the assembly. Examining it a bit further, the outer edges of the hole opening makes it look like the shard may have been spinning around at some point. But when I got to it the shard was firmly entrenched in the jet opening. Unscientifically, I blew compressed air through a good jet aimed at a sheet of paper and compared it with this damaged one. The damaged jet is allowing some air through, but it didn't seem to be as much as a new jet.

Whats the holdup with the pistons? I'd assume they would've been shipped with your cylinders?

Pistons ship separately (provided by JE). They take a week to get to Cali from Chicago where LNE is. All in all the estimate of 5-6 weeks was pretty accurate.

I see... I was told 6-8 weeks for mine. I'll be driving my pickup till then..

Complete engine rebuild in progress. Thread closed. New thread to be opened soon.