What happened to my Porsche?
01-16-2008, 08:50 PM
#31
Instructor
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Anyhow, the trouble is a new/improved IMS with a larger bearing is available (and is fitted to newer 996 engines) but is not retrofittable to older engines. The new IMS has a different camshaft drive sprocket that would require a change in crankshaft and camshaft drives.
01-16-2008, 11:13 PM
#33
Burning Brakes
- MY98/99 (3.4) C2: M96/01
- MY99 (3.4) C4: M96/02
- MY00/01 (3.4) C2 & C4: M96/04
- MY02/03/04 (3.6): M96/03
M96/04 updates: Porsche changed to e-gas, modified the fuel injectors, used a new crankshaft, a new air injection pump, auxiliary drive belt tensioner housing as well as a new alterator and pulley.
Further updates for the M96/04 engine for MY01: new crankshaft and timing chain (plus self adj. mechanism) and the intermediate shaft on the camshaft received attention again. Fuel injectors were again revised as was the auxiliary drive belt tensioner.
The 3.6 M96/03 engine was basically a complete new engine.
01-17-2008, 12:03 AM
#36
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Bronston,
Sorry to hear of your misfortune. Glad to hear it is still under warranty...whew!
This is the right place to bring your mechanical/technical advice type questions. Doing searches and reading about something going wrong with your car leaves you on an island. It doesn't come close to the advice and support you will find here. Best of luck.
Andy T
Sorry to hear of your misfortune. Glad to hear it is still under warranty...whew!
This is the right place to bring your mechanical/technical advice type questions. Doing searches and reading about something going wrong with your car leaves you on an island. It doesn't come close to the advice and support you will find here. Best of luck.
Andy T
01-17-2008, 12:27 AM
#37
Burning Brakes
Btw, MY98 was sold in the US but sold as early MY99, so we've basically the same 2 model years in the US as the rest of the world, the market here just works different and we're used to call late old model year cars different.
01-17-2008, 05:37 PM
#38
Race Director
01-17-2008, 07:07 PM
#39
Race Director
Failed Intermediate Shaft Bearing picture (link)...
I have a 40th anniversary I purchased used with 10,000 miles last August. I put an additional 5000 miles since then. Today I drove about 15 miles (normal drive) to my dealer, Barrier Motors in Bellevue (Seattle) to take advantage of the lifetime free carwash. While waiting in neutral with the engine running I heard some very strange clattering, scraping noises coming from the engine end of the car. I visual inspection showed nothing but to be safe I drove over to the service bay about five blocks away with the engine making the noises for a bit but which stopped before I got there. Once there we looked for a possible source of the recent noises to no avail. After shutting down,the engine began spilling oil from the bell housing, not dripping, not gushing, just a steady flow. They guessed it might be an intermediate shaft failure. After reading this board for the last few months I gather this is not unheard of. The mechanic indicated that they do engine repairs as well as engine replacement. What are the pros and cons? The service records indicate that RMS was replaced in the past. Should I expect (or insist upon) an engine replacement? Does the two failures suggest a problem with this particular engine? This is my first Porsche and this type of dramatic failure is not confidence inspiring.
BTW it is still under new car warranty with an additional two years of CPO coverage beyond that.
Is this why I was mildly flamed on a previous post wherein I admitted to using an automated carwash? Did my car commit suicide rather than submit to another automated scrubbing??
Your thoughts and suggestions, please.
BTW it is still under new car warranty with an additional two years of CPO coverage beyond that.
Is this why I was mildly flamed on a previous post wherein I admitted to using an automated carwash? Did my car commit suicide rather than submit to another automated scrubbing??
Your thoughts and suggestions, please.
As I mentioned in another post the owner of the car shut off the engine before the bearing failure had time to take out the engine.
Just an educated guess, but I'd say the engine had just seconds before this failure progressed to total engine failure.
http://i9.tinypic.com/67dtx6g.jpg
Sincerely,
Macster.
01-18-2008, 10:47 AM
#40
Burning Brakes
http://www.autofarm.co.uk/engines/wa...led/shaft_tech
It is a little hard to tell from the description, but it looks like the seal was changed for MY03. The real problem may be the bearing is undersized as this page says that the bearing size was increased for the 997.
01-18-2008, 11:39 AM
#41
Getting the car back next week.
They have all the parts and the engine is starting to go back together with completion due next week. It seems that there have been several "improvements" to the intermediate shaft along the line. I have been assured that the "new" shaft/bearing is "better". One rep stated that the new shaft/bearing I am getting is "larger and stonger" but fits into the same opening in the case????? At this point there is little I can do but accept the repaired engine. I know many on this board have had years of wonderful driving. This is my first Porshe. I have admired these cars since the late 50's when I worked a bit after school in an imported car shop behind my home. If I had had more than six months of good service before the engine puked I would not be as uneasy with the car as I am now. Porsche takes the position that this problem was so infrequent as to not warrant redesign. In their universe it may be a fraction of a percent, in mine its 100 percent.
As I noted in a previous post, go scan a Corvette or BMW M forum. There doesn't seen to nearly the number of replaced/repaired blown engines. Porsche has some great engineering and some not so great.
Finally, thanks to all who have chimed in with information and support.
As I noted in a previous post, go scan a Corvette or BMW M forum. There doesn't seen to nearly the number of replaced/repaired blown engines. Porsche has some great engineering and some not so great.
Finally, thanks to all who have chimed in with information and support.
01-18-2008, 06:23 PM
#42
Race Director
Well, your best source of info should be the service manager...
They have all the parts and the engine is starting to go back together with completion due next week. It seems that there have been several "improvements" to the intermediate shaft along the line. I have been assured that the "new" shaft/bearing is "better". One rep stated that the new shaft/bearing I am getting is "larger and stonger" but fits into the same opening in the case????? At this point there is little I can do but accept the repaired engine. I know many on this board have had years of wonderful driving. This is my first Porshe. I have admired these cars since the late 50's when I worked a bit after school in an imported car shop behind my home. If I had had more than six months of good service before the engine puked I would not be as uneasy with the car as I am now. Porsche takes the position that this problem was so infrequent as to not warrant redesign. In their universe it may be a fraction of a percent, in mine its 100 percent.
As I noted in a previous post, go scan a Corvette or BMW M forum. There doesn't seen to nearly the number of replaced/repaired blown engines. Porsche has some great engineering and some not so great.
Finally, thanks to all who have chimed in with information and support.
As I noted in a previous post, go scan a Corvette or BMW M forum. There doesn't seen to nearly the number of replaced/repaired blown engines. Porsche has some great engineering and some not so great.
Finally, thanks to all who have chimed in with information and support.
My second-hand info is that while a new/improved intermediate shaft seal (consisting of multiple o-ring like seals replacing the single o-ring) and better sealant on the threads of bolts that hold the seal in place can be retro-fitted a larger intermediate shaft bearing is not.
The larger bearing comes courtesy of a different shaft with besides the larger bearing a different style of crankshaft to intermediate shaft chain drive. Even though the intermediate shaft may fit in the older engine cases the chain drive is incompatible and nominally would require a crankshaft swap (along with the chain and almost certainly any chain tensioners/guides that help keep this chain properly tensioned and in place).
As the link to the Autofram web site shows, Autofarm remachines a new style intermediate shaft with its larger bearing removing the new style chain drive sprocket and fitting an old style chain drive sprocket.
Thus one gets the larger bearing (and at the same time the better seal) while the new shaft remains compatible with the existing crankshaft and its intermediate shaft drive chains.
Of course even with the larger bearing this shaft fits the existing engine case.
From the picture of the failed intermediate shaft I posted shows the bearing failure includes bearing races that appear to be integral to the shaft, I'm not sure how a larger bearing could be fitted to an old shaft.
(Well, having some machining background, perhaps a new old style shaft could be remachined to take the larger bearing. But I note Autofarm didn't go that route so maybe there's something wrong with my idea that renders this not a solution.)
My memory is not always reliable, but I seem to recall when speaking with the tech about the M96 engine from which that shaft came speaking to him about the repair and what was could be done to see it didn't happen again (for this engine anyhow), I was told that the old style intermediate shaft was fitted, there was no other option.
Now maybe that's changed, and Porsche has managed to produce an old style intermediate shaft that remains compatible with the crankshaft but does come with a larger more robust bearing.
It might be an interesting question to put to your service writer/manager.
Sincerely,
Macster.
