GC996

Any idea why 2002? What's different about the design?

purelydriving

Worth having Vollig Autoworks look at it. They’re a great place for Porsche work in San Diego

Chris(MA)

Could be vendor quality control problems or swapping vendors. Porsche during the boxster/996 had other vendor problems like a bunch of bad blocks they tried to re-sleeve which went about as well as you'd expect. They were all pretty much swapped under warranty

Mr.Mike111

yeah I do like Vollig, the car is at Charlie’s Foreign auto. I like them too and they’re closer to where I live

Porschetech3

I'll offer up my armchair opinion/hypothesis also..

I don't think it's bore scoring ......bore scoring doesn't go from 0-to-boom like that ...

I don't think it's a failed rod or rod bolt.........rods and rod bolts don't fail at 4k rpm

I don't think it's IMSB ...if you have the "Solution" they have a "soft fail"...not a "hard fail" like ball bearings can have...( marbles in a tin can)..

I don't think it spun a rod bearing/oil starvation...........4k rpm isn't that high and you didn't say you had been in a long high-g turn

That only leaves about two others, dropped a valve seat or popped a timing chain....if it was a 2002 I'd lean toward a dropped valve seat, but since it's an 2004 I'd lean toward a popped timing chain...

What are the collateral damages from a popped timing chain?

Well that depends on the RPM at the moment the timing chain pops...
All m96's are "interference engines" meaning if the cam stops turning, the pistons "can" hit the valves..
.If the timing chain pops at a red light, there is a good chance the cam will stop rotating in a position that the pistons do not hit the valves,
If the chain pops at 4k rpm most likely the pistons will hit the valves and further collateral damage will occur ( chain reaction), the extent of collateral damage/chain reaction can be as small as just bent exhaust valves, all the way up to broken valves, busted pistons, broken rods, busted crankcase/cylinders..ie. total destruction

I remember back in 2010 when Porsche went to aluminum bolts for the vario-cam vane adjusters in the Panamera, Cayenne and Gt3...When I first saw them during P10 Training I said" uht oh, that looks like trouble"....But Porsche was very proud of the weight savings of the aluminum bolts and other updates of the vario-can...Then sure enough, the aluminum bolts started popping the heads off them...cams would stop turning just like if the timing chain broke...Porsche issued a "Service Action" ( ie. Recall) to replace all the early 2010 Panamera, Cayenne, Gt3 aluminum bolts to steel bolts, but not before many had failed..

If the engine was at a stop light when it failed, all we had to do was find all the bolt heads and install new steel bolts and re-time..all good..but if the engine was at high RPM when the aluminum bolts popped, it had to get a new engine due to all the collateral damage/chain reaction..

I'm hoping your engine suffered minimal collateral damage and can be saved.....

BTW ; what usually starts this happening is a little roller shell from the timing chain breaks off and gets sucked up by the return oil pump ( scavenge pump) which locks the pump, this puts excess stress to where either the return pump breaks the drive, or the exhaust cam gear drive breaks or the timing chain breaks...since the timing chain now has a weak link, it is usually the first to break.,,then the further chain-reaction/collateral damage depends on the RPM's....

Mr.Mike111

Thank you for sharing this. Super informative and hopefully I should know within a day or two the extent of the damage.

TheUnscented

Hopefully not a catastrophic failure, but there is life after the M96….

Ahmet

These engines sound funny with a bad ignition coil too... A broken timing chain is easy to check for so hopefully you'll hear something back soon. If you were so inclined, you could pop out the scavenge pumps and start turning the engine over manually. If either of them don't move (or the engine doesn't want to rotate), you're going to have a bad day. Not a foregone conclusion at this point though, hope it's something more minor!