Help me to do the job properly please!
 

Hello guys,

After tear down of my engine (3.6 964 "P").
The crankshaft has spun a bearing in cyl. #3.
Sadly here (Greece) the only way to to repair it is to ground the damaged journal as to be round again, then had it hard chromed and then a final re-grinding.My grinder is very understanding and also cooperative but he told me that he never have done to a Porsche crankshaft again (lot of times in other brand cranks).I read that a crankshaft may be cracked when the grinder fail to do the "radius" finish or something ???
Is there some info / tolerances that will be help my grinder to do the job as much as possible accurate ???

THANK YOU SmileWavySmileWavySmileWavy

Jim:

Porsche cranks are NOT hard chromed and if you do that, it will ruin the crank.

These are nitrided then straightened as needed.

Send it to Germany to an expert!!

Hello Steve,

Thank you for your directions.
Any reputable machine shop in Germany ?

Please also take a look here :

http://66.236.61.177/showthread.php?t=151371&highlight=crankshaft+hard

I am not familair with the shops in Germany to know who is competent and who isn't (besides Ruf, anyway).

Regarding that thread; there are the right ways to do something and the cheap/wrong ways,....Caveat Emptor on the latter,... :)

I would get in touch with www.mittelmotor.de and ask them what they think.

Hard chroming is not an acceptable process for crank journals-- in the case of crankshaft otherwise unavailable used or new, the journals are welded up, the crank re-machined to size and re-hardened. I imagine that the process of doing so is probably expensive, but the person to talk with in the USA is Armando at CCR.

You would be far better served to obtain a used crankshaft, even from the USA with the Euro the way it is you would be better off.

If you ever in doubt as to a crack in a crank, simply "ring" the crank.
Hold the crank in one hand by one of the counterweights, let it hang down, strike one of the other counterweights with a small hammer or wrench (not on a journal), and listen to the sound it makes.
A good crank will ring like a bell, a bad one will have sort of a "doink" sound (short, and off-key).
I have been doing this for over 40 years and have had several discussions with machine shops as to the reliability of the method, however, I have found bad cranks this way that took the shop over an hour with a Magnaflux unit to find.
Quick, easy, and definitive.
Hope this helps.
Bob

Bob : I make the test twice.It rings like a bell loud and clear.

Update : I found a shortblock engine (crankcase still assembled with con/rods,DMF,distributor.
All are in excellent condition and seller is accept to tear down the engine and have all the parts checked by any machine shop before payment !Now what is a fair price for these parts guys ???

Thank you,
Jim

a "shortblock" to me, means case, crank, rods, pistons and cylinders. i would think value to be in the $2000 to $2500 range if the crank is good. you may want to use the case also, being that yours is full of metal bits from the spun rod bearing.