carlege

WOW!

Chris White

Could be worse – it could have been on the Cross Bronx Expressway!

I haven’t seen the carnage but from the description of the break (just below the wrist pin) it sounds like rod fatigue. The engine had stock forged rods and 25,000 miles and almost 10 years since the build. I have seen the rate of stock rods failing going up in the last couple of years, after all the ‘youngest’ 944 rod is over 21 years old now.

I use to be ‘OK’ with reconditioned and magnafluxed rods in a track car….I may have to rethink that. Magnafluxing will catch a crack that has already started but it won’t help with fatigue just before the crack starts.

APKhaos

It must drive you crazy when you read 'My CW engine blew up' without any mention of the fact that it was built ten years and 25K miles ago! I agree that the stock forged rods with 100K miles plus are probably candidates for stress failures. My 89 S engine has just 36K miles, but its been a dedicated race appliance for most of those miles so I might have to replace the rods next refresh.

Tedro951

Ouch.

toddk911

So on the rebuild the stock con rods were re used?

I guess I need to add those to my rebuild list to be safe.

ringnalda

Hey Josh, If you think you will have a motor for $1750, what are the details on that engine? Can you give me a call or send me an email mrcbx@@att.net (remove one @)

ringnalda

Hi Chris, I was wondering if the pistons used in this engine were the same weight as the originals? It sounds like fatigue to me too, and I'm glad it didn't let go at higher speed! Perhaps Carillo rods are the way to go?

Chris White

The pistons are a lot lighter than the stock ones! Stock 951 pistons might as well be made out of lead (around 800g).
BTW – the shop in Long Island sent some pics and that jogged my memory a bit – the rods in the engine were the original 1989 turbo rods (some might call it a ‘Turbo S’ but since it was the only turbo offered that year the factory stopped calling it an ‘S’). Now I remember that the rods in that engine were the cast rods and at the time the option for aftermarket rods was not taken and the though was that if Porsche used these rods in a ‘Turbo S’ then they were good enough for this project.

I would go with the Carillo, Pauter or Wossner (if available) rods. Much lighter and 20+ years newer!

Chris White

Maybe just a little!
It doesn’t take much to blow a stressed engine up – even a well built one. The more power you get the less the safety margin is – that’s just a fact of life. Any engine that sees a lot of track duty needs to be checked over often.

See my previous post – there is a good chance you have cast rods in the stock 89 engine. While they may have originally been the same strength as the sintered rods they are more susceptible to fatigue and the area around the rod near the wrist pin is weaker.

ringnalda

The car had a donor engine installed, all the aftermarket goodies were transferred and I enjoyed this car at a few PCA events in 2012. It runs like a top. The motor internals are all stock, with only 70k miles so should be good for some time. I just found a 996tt so will probably sell the car to any interested parties...?

Josh B

An updated pics? Price?

MichelleJD

Glad to hear there was a happy ending!