Cheburator

Ok, smarty pants...

How do I know the used crank is straight?
How do I know the new glyco bearings that I would have to buy are on spec?
How do I know the used crank has no micro cracks?
What is my comeback to you?

Oh, just because you say so...

Knowing how **** Porsche is about standing behind a product, I think I would take my chances. In the meantime, if you feel better about using a 2nd hand one, go ahead. That's what makes the World go round - difference of opinion...

ptuomov

If you buy a used crank, you will need to have it measured and possibly turned down. A use crank that is guaranteed to be within the spec is obviously worth a lot more than a used crank that is not guaranteed to be within spec. My personal opinion is that it makes no difference whether an induction hardened crank is undersized by .25mm or not. What matters wheter the crank is reliably within its spec.

James Bailey

Plus the Porsche warranty is IF the crank fails......you get another crank PERIOD ! no rebuild costs, no rods, pistons, or block. You have a replacement crank with no place to use it.......that does not give me a warm fuzzy feeling

GregBBRD

My "rule" of thumb is to never use a turned crankshaft...only standard/standard cranks, for my engines.

I'd expect that a used 928 crank, worth selling, would need a micro polish in the worst case. I'd certainly make this a condition on any purchase....

The day comes that I can't measure a crank to see if it is straight or measure it to be the correct size and match it to the correct bearings, is the day I will hang it up.

James Bailey

Well know local crank maker uses Chinese suppliers to furnish low cost "stroker" cranks for popular US engines....some of the units fail final inspection after being imported.....So they turn them down undersized and sell them at a discount to shops which sell completed stroker motors knowing that the ultimate customer is NOT going to tear down his "new" engine to check to see if it is a std std crank..... Trust me on this one....

Cheburator

Perfectly valid points. However, when my GTS crank became toast, you had none in stock. In fact, Mark T had one, Mark C in the UK had one, and also Adrian C in the UK had one. That was it. None at any breakers/salvage yards at all. The sellers claimed the cranks were good, and I am sure they were as all are fine members if the Rennlist Community. However I still had to have them checked and measured, and also shipped, bearings matched etc... Or I could walk into my local Official Porsche Centre, hand a bit more cash over and receive everything within 2 weeks, with bearings included and the backing of Porsche. Hmm, a no brainer for me...



Cannot see how this applies to this particular situation.

Let's agree to disagree on this one and just put it to bed...

Imo000

If a crank doesn't have a spun bearing, it will be straight and will not have micro cracks.