silotwo

2004 996 C2 43k miles

At the moment the car is back at the dealer - repeated CEL and code readout for misfire cylinder six.

Here is my concern and the lengthy story: Car is CPO and had a bad 4th gear synchro when I purchased in august 2007. Finally decided to chance having the dealer repair the trans under CPO. Thought things were good when they were able to honor my request to for a factory rebuild rather than dealer repair.

With trans out they find IMS seal slightly seeping, I stop by and confirm, they get warranty approval. Also - I had the 45k service done at the same time.

I pick the car up - clutch feels stiff - I paid for a new throwout bearing - two days later CEL comes on - first time ever since I owned the car, bought with 22k miles. I bring it in, they say misfire cylinder 6, clear code and they say car runs fine. I mention noise from the engine compartment when I first picked it up from the repair. The mechanic gets scared - refuses to let me take the car. Next day I call - yes, car is fixed, they had installed the incorrect IMS housing, overnighted the right part and dropped the trans and replaced with correct part next day. They claim all is fine now, wrong part caused a timing problem - no worries of other damage they tell me.

Pick up the car, notice the clutch feels normal again and assume the wrong IMS housing was stressing the pressure plate, drive a few hundred miles and she is running and feeling good. Day three CEL comes on again but goes out after revs go above 2500. Next morning, CEL comes on, car runs terribble, feels like plug wires are crossed, drive straight to dealer, leave the car running and the ***** shut it off and when they restart it runs smooth but CEL is still on.

They give me a loaner, call me late afternoon and say they found the problem and will be replacing the lifters on the engine bank with cylinder 6. I ask if this is related to the incorrect IMS part - NO WAY they say - pure coincidence.

I stop at dealer today - car is not taken apart yet. I question their diagnosis and then tell them I am not comfortable with repairing one bank - if it is not from IMS screw up then it must be wear - and I would think wear would be even on both bays. They say no, only misfire code is for cylinder 6 - can only get warranty approval for one bay.

Now - NOTE that NO Codes were recorded with the read out for the 45k mile service, which was done in their shop right before the removed the trans. They screw up the IMS seal replacement and suddenly the car is throwing misfire codes and I am expected to believe it is pure coincidence.

Now I do remember way back in the day when I was a mechanic and people would try to tell me that when I did a brake job on the rear axle that I blew the generator because the next day their generator light came on (told you it was way back). But - it just seems to me that the IMS associated to timing is too close of an association for me to simply accept "pure" coincidence.

I am looking for your thoughts, suggestion on how to handle this.

porsche52

Wow, what dealer is this? I am a tech here in CO. If they installed the wrong IMS flange, it could be very ugly! Not saying it is, but maybe. The problem is the early IMS flange had a longer nose on it, deeper depth into case. I have heard a tech doing this, cracked the engine case!! No bueno. But the thing that has me scratching my head is the clutch feel. the IMS flange has no affect in how the pressure plate bolts to the flywheel, none, silch, nada! You said they replaced the T-out bearing? Its possible they did not lube the clutch linkage very good the first time, or maybe they installed the wrong t-out bearing, or maybe the bone head who installed the wrong IMS flange did not properly torque the pressure plate bolts? But I can tell you for shure 100% that the IMS flange can no way effect how the clutch feels. Now, it is possible that by installing the wrong IMS, that they screwed up cam timing, but usally it would effect that entire bank, meaning you would have misfires for 4, 5, and 6. So that makes me think that maybe it is a lifter failure that is isolated to just that cylinder. We have seen a fair share of lifter failures! Have them pull that plug and look at it, if they have not already. What kind of noise did you have coming from the engine when the tech got scared? Tick, tick, tick?

Below are some IMS flanges from LN Engineering, and OEM. This simply illustrates the difference between the 2 different styles. The early cars had the longer one, bearing marked 3.2. Your car requires the shorter one, marked x-51 in that pic. In the bottom right pic you can see were the IMS flange is located, below the crankshaft, now way it can influence clutch feel!

silotwo

Thank you Porsche 52! First let's make sure I am using the correct reference to the part - the incorrect part is the part to the left of the one marked X-51 - I think it might be called the IMS end plate cover. The part number of the final one the dealer installed is 996-105-024-01 Shaft Housing - as listed on the service order. The correct part has a taper on the side that is facing the counter top in your photo. The one they first installed had no taper at all, perfectly flat surface - looking at the first service order I am guessing it was 996-105-017-02 shaft base. All of the other parts listed, with the exception of the seal, are hex nuts and screws. I compared both my original part and the incorrect part on a work bench and the overall height appeared to match - the only difference, which I thought very significant - was the taper.

Prior to the service, I never heard any tappet sounds of a tick, tick, tick. Tuesday when they had it running in the shop, I definitely heard that sound, coming from the right bank if you are sitting in the drivers seat. Yesterday the mechanic referred to that sound as the reason he was diagnosing a failing lifter as the reason for the mis-fire. I couldn't follow his logic though - he made it sound as if the lifter was failing to bleed down on the low cam setting and mentioned the vario cam plus system.

The mechanic told me on the day I heard the ticking that the engine was "throwing misfire codes all over the place" on the bank with cylinder six. The service manager told me "nope" only cylinder six. Of course, like I said, the boob intentionally shut it down and restarted it before pulling it in to the service bay. Service managers answer is that the misfire in cylinder six caused the car to attempt to adjust timing which is why the mechanic read mis-fire codes from those three cylinders.

The sound I heard when I first picked it up was similar to a bolt rolling around in the engine bay - I originally thought the mechanic left something in the bay or something wasn't connected properly - but that sound went away on the drive home and I couldn't reproduce it. Also - I drove the car 70 miles round trip - total 140 miles - the very next after picking it up and it ran fine, no CEL - ran strong.


I called late today and the service manager said "we ordered all the part to replace all of the lifters in that bank" I asked if they removed the cam cover to inspect anything first and he said "no" we know what the problem is. When I asked again why only service one bank - he laughed and said "because you only have a problem in cylinder six, we are only replacing the lifters across the entire bank because Porsche says we have to". Also - the service manager said that in the 4 years he and his two mechanics have been there - they never ever experienced a failing lifter - and if it weren't for my service history with oil changes an no more than 7,500 miles - they would assume the engine wasn't serviced at the recommended intervals.

So - and thanks in advance for the time you put in to helping me -
1. Could the incorrect IMS cover - driven about 200 miles - have damaged the engine?
2. Could it have changed the cam timing?
3. In your experience, is it okay to replace the lifters in just one bay? car has 43K miles on it

In your opinion, as this is a CPO car and since it is this dealer who performed the initial work - should I allow them to continue and gamble that if there is a related problem I can deal with it at a later time? CPO expires in january of 2010. I do drive the car daily.

Thanks for straightening me out on the clutch feel - I can only assume the original install was incorrect and perhaps at re-install he got it right. Drives me crazy that they didn't test drive the car, I have to assume that they didn't because the clutch feel was that obvious - it actually felt as if the clutch was not fully releasing - I could feel the throw out bearing on the ball of my foot with out placing any pressure on the clutch pedal.

I apologize for the lengthy post - but since they chose to not tear anything down - and I am out of town all next week - I think I have the option to pull the car from their lot and take it to a different dealer when I get back in town. Not sure that a different dealer will appreciate taking over a suspect repair job though.

Oh - and the dealer is Knopf Automotive in Allentown Pennsylvania - Porsche-Audi-Mercedes.
Thanks again

porsche52

Hey no problem man. The correct IMS flange for your engine is the 996-105-024-01. This is the one with the taper, next to the bearing marked x-51. Now that I think about it, the failure that I was thinking of was when a tech installed a later IMS flange (the one with the taper) into a early engine (3.4L). Due to that taper it will not fit unless you are retarded and draw it in with the 3 bolts, effectivly pressing it in until something gives, in that case it was the engine case. So that ugly scenario is not possible here. BUT, having not done and our witnessed what this dealer did, I cannot speak with 100% guarntee that no damage occured by installing the incorrect IMS flange. This is the akiles heel of this power plant to boot.

I dont know how familiar you are with vario cam plus but it is pretty cool. It sounds like he was trying to tell you that the intake lifters for #6 were stuck in the high lift position maybe? I am having trouble following what he told you too.

porsche52

Regardless if the problem is only at #6 or not, when they repalce all the lifters they will have to remove the camshafts, so cam timing will be re-set. I shure hope the tech is a good guy and reads the manual or has had this engine apart before!! Because the cam timing procedure for this motor bites more techs in the *** then any other engine we work on. I may be crazy, but I think the engine must come out for this? I will check tomorrow.

A bolt rolling around type noise! I dont know what to think about that. Time will tell.

Well I can tell you that lifter failure is by no means common, but they do fail. They sound like they are not a very high volume dealer(2 techs). Ask Beverly Hills or Champion porsche the same question and they will tell you different. Our shop has replaced several for various reasons over a couple of years, and yes, you always replace all lifters on the bank of question, but do not usally inspect/replace opposite bank unless you find alot of debri in the oil and or strong evidence to warrant that. The vario cam and vario cam plus system is very prone to contamination from debri, very, very small oil passages control the system. If I were doing the reapir I would repalce both vario cam and vario lift actuators as well on that bank, and flush out all oil passages etc. They probably will not let you do this but if I were you, I would demand that I get to inspect the bank 2 cylinder head when the cams and lifters are removed. Check for metal debri, scoring, etc. Something tells me that the bolt rolling around noise could have possibly been something to do with the IMS flange deal. Have them pull the oil filter and inspect for metal shavings etc.

I would stay with them until the fix this issue, lets face it, they are married to it now. If they continue to f-things up, you may very well end up with a new re-man engine or a complete engine re-build on there dime!! If they fix it and everything is good, then hell yeah I would be looking for a new Dealer or Good Indy to go to. Good luck with this, keep us informed on what happens!

silotwo

Thanks again Porsche 52. Originally they were going to tear it down so I could look at it before I leave town but at this point I think I just need to let the issue run its course. I have a high level of confidence that my engine will be an on the job training experience for these guys. I do remember the mechanic being very nervous when I told him about the bolt rolling around type noise and he definitely said that if you screw up working on the IMS it could require re-timing the cams and he really wanted to avoid needing to do that. I am thinking he has read about it but doesn't have any hands on experience with it.

Thanks again - I'll wait it out and post when we have some progress.

porsche52

Just to update, the Engine must be removed to R&R camshafts as per workshop manual. So the engine will be on the ground. This is a very good time to look around the car for anything that possibly needs to be fixed. Possibly save alot of $$ in labor to do it now. Coolant bottle, mounts, etc. But with only 43k nothing will probably be wrong.

99firehawk

Lifters are a common failure, 99% of the time it is bank 2 (cyl 4-6) and generaly tip tronic cars only.
But not unheard of for stick shift cars. the engine does need to come out as ther is no way to torque the cam drove bolts with the engine in.
The ims should not have any effect on your clutch feel, and theres no way they can hurt a lifter though any work they have performed.

silotwo

Thanks Porsche52 and Brad. They never mentioned dropping the motor - they referred to removing the cam cover a few times. The dealer now has the car in the service bay - but in the air tail in - I've been there enough to know that when they drop a motor the car is nose in. I stopped by today so I could only look through the shop door windows to see where they had the car. Could be that they are inspecting something - or could be my worst fear - if the mechanic makes mistakes with a remove and re-install (the clutch and the IMS seal) I have little confidence that they are competent enough to truly do a repair or a re-build. I guess all I can do is trust that they will follow the workshop manual and pay attention to specs.

Unfortunately I will be on the west coast all week - leaving tomorrow - so I won't have a chance to stop in and check on things. I will try to swing by on my way to the airport for a peek and a quick, yet polite, chat with the mechanic.

Other than that, it is out of my hands and I guess what will be will be.

I'll keep you posted. Thanks again for your help.

silotwo

Update as of monday morning. I was able to stop at the shop and inspect the car and talk to the mechanic. Feeling a little better in that I was able to see and touch the lifter that is stuck in high mode. Cam looks fine as do the lifter bores - mechanic confirmed that the engine has never been apart before. Also, coil pack for cylinder 5 is cracked and they will replace that as well.

When I mentioned cam timing he did state that the engine will be out, although he looked pretty nervous about timing the cams and said he hopes it goes well with the bank he is working on because he wants to avoid timing the cams on the other bank. Question here - can we get away with timing the cams on only the bank that is being worked on.

Also - took Porsche52's advice and I will have the drive belt replaced and the mechanic is considering changing out the coolant resorvoir even though it looks fine and he thinks it is the latest design. I also asked them to consider changing the spark plugs and inspect anything else that could be easily replaced when the engine is out.

Although my automotive theory is well outdated, I still know enough that I now believe that the incorrect IMC housing has no relationship to the stuck lifter. And to give the dealer their props - they have been honest with me - they could have hiddent the fact about installing an incorrect part - mistakes happen - honesty means a lot in the end.

Feeling pretty good about this board again too - I stopped visiting last fall because the hottest debate was about Australians and skin cancer........

Doug Donsbach

Timing is set independently on the two banks. If he starts working on the other side, that should set off some alarms! As an aside, I'm not sure what the big deal is with setting the timing on one of these, assuming you have the required tools.

silotwo

Thanks for the info Doug, I appreciate it. I am assuming the mechanic hasn't yet had the experience so he might be a little apprehensive. That could be good, he might be a little more careful this time around.

porsche52

Good to hear silotwo! So the intake lifter was stuck in High lift mode huh? Solid lifter now, the way that lifter works is oil pressure is fed into the lifter housing via the vario lift solenoid were it then acts on a pin inside the lifter locking it, thus creating a solid lifter. In low lift the, high lift profile of the cam pushes down on the outside surfaces of the lifter and colapes it, thus allowing the low lift cam profile to act on the center portion of the lifter. Low lift = 3.6mm and high lift = 11.0mm. (Cayman spec, 996 maybe different, but very close). Only 1 lifter failed? Any debri in oil? I hope the tech inspect the lifter housing very good for small debri in the oil passages, brake clean and blow some compressed air through.

Yes you can time just one bank, but you must, I repeat MUST know for shure that the other bank (bank 1 in this case) is on TDC compression when you install the bank 2 cams in on overlap!! All he needs to do is pull the cam plugs, (little green plugs, at the end of the cam cover) to see how the cams are allocated. He will be able to check bank 1 cam timing too using the special tool that installs into the rear of the camshafts. Some people just get freaked out by cam timing, and IMO it comes from a lack of general 4 stroke basic knowledge. (Intake, compression, power, exhaust). Because I can look at a cam and tell you what stroke that piston is on without pause, alot of techs this day in age cannot, they just dont see this stuff enough. It is a must and should be organic to someone who is rebuilding any engine. The tricky part about setting this motor up is it is different than the majority of the engines we do. 996-997 turbo and GT3 cam timing is cake, early 1st gen vario cam 996-986 cam time is a liitle different but pretty easy. All your air-cooled engine are pretty much the same, from using a Dial indicator on the early cars up to 964's, to the 993's by far are the easiest IMO. But then you have the Vario Cam plus 996-997 and 986-987 (cayman) engine, the biggest thing I can think of without having the repair manual out in front of me is how they want you to get rid of all the slack in the timing chain. Cams are installed on OVERLAP (intake is just opening and exhaust is closing) cyl #1 or #4 pending on what bank you are doing. Cyl #1 the Int. and Exh lobes point towards eachother, cyl#4 they point away from eachother. (FYI, cams are installed on overlap because they are relaxed, no valves open, no pressure on cams for that bank), loosely fit the bearing caps, fit the vario cam vane adjuster, fit the exhaust cam gear (with the holes half coverd) fit the tensioner, or dummy special tool tensioners. Now this is what gets people, at this point we are 60 deg BTDC. Rotate the crank to TDC,(removing slack from timing chain) the exhaust cam bolt holes should now come into view, install the special tool into to back of cams, sets timing, torque bearing sadles. perform torque on the intake & exhaust cam bolts (4) remove cam timing tool from back of cams, install special tool that looks like a old school telephone, torque (new) intake cam bolt and you are done. Rotate crank 360 check other bank with tool, rotate 360 re-check this bank. I think that is how it goes? But my point is stay calm, turn the cell phone off, read the manual and get er done.

99firehawk

Doing that will lead to
A. car not running
B possibly bent valves

Timing Is set at tdc. You set set the cams at the u6 marking on the crank pulley (60 degress before) Then install cams (in overlap) then roll the motor to tdc and pin the crank. Then inital tighetn the cams 37 ftlbs on the intake and 10.5 on the exhasut. Remove the cam tool. add 110 deg to the intake cam.
Wrap it up .

porsche52

Thats right, I miss typed there. Oops. From now on you must call me Dragon, Firehawk! You cheated though, @ 7:25 am you were probably at work drinking your first cup of coffee reading the WM. Unless you are one of those guys who can pull torque specs out there butt. At 1:12 am (11:12pm my time) I was having a beer and typing from my butt I guess. Thanks for correcting me