crank problems

[jsbc]

Hi has ony one had problems with cranks being pushed forward by the tourque converters or what ? I have two 928s my second was bought as a dead car seized engine something caused the crank to push forward ,it ran through the thrust until the crankwebs hit the bearing webs on the block pushing the crank down through the mains finally seizing it.I split the case machined the halves had it line bored ,crank straightend ground 1st over size on mains and the thrust white metalled up to give spec clearance on the thrust plus a host of other things,it now runs like a new car.The question is I have heard of another car with the same problem its motor is being rebuilt and on checking my other car I can pull the crank back about one mm so the thrust on this is also stuffed
they are both autos the other car i dont know.I can't see this happening on manuals but has any auto owner experienced anthing similar.

[Danglerb]

TBF thrust bearing failure is OFTEN reported in the forums, typically the block is damaged too much to save. The actual level of occurance though isn't clear, but annual checking of the crank shaft endplay and pinch collar is a VERY good idea. Here is a search link with a few hits.

http://www.google.com/search?hl=en&q=thrust+bearing+928&btnG=Google+Search

Rlist recently has a nice write up with how to measure and pictures.

It seems to be strictly a problem with either 85 or 87 and up automatics after Porsche removed some clip from the driveline.

Constantine offers a permanent fix, and I think some others may have found ways of using the earlier clip, but I am all 5 spd and haven't followed details all that closely.