Out of Round 3.0 Crank
 

Is an out of round crank an issue with the 3.0 case? I know that the crank is not recommended for re-use, but what about damage to the case? Is there any issue with a line bore? Or are they usually within spec?

Help would be greatly appreciated.

James

Give Armondo at CCR a call. He may be able to straighten the crank.

http://forums.pelicanparts.com/porsche-911-technical-forum/333299-ccr-crankshaft-grinding-armando.html

Thanks for the reply.

I am not worried about the crank, I would replace it. I am trying to determine if the case is frequently damaged by the "out of round" crankshaft. If the case is damaged, would the repair be any issue for a car that would be an autocross/track car?

I would just send the case out for inspection and align bore if needed. The machinist should be able to determine if the case is serviceable.

If you can put new mains in, torque to spec and turn over the crank, go with it. A lignbore aside of the expense, the bearings are out of the world expensive. Try by solving your own problem and if you cant, then look help.
Bruce

out of round, meaning what? bent? one journal had a spun bearing?

Yes, how do you know your crank is out of round? And just what do you mean by out of round? Is one journal not round, as measured with a micrometer in at least two axes 90 degrees apart? Or did you put the crank up on V blocks, and find that the center main journal on the crank moved up and down, as measured with your handy dial indicator?

I can see why you are concerned, as it has to be tough for the crank to bend when clamped into a case.

If you do have to have the case bored, consider having the technique used on the frequently bored magnesium 2.7 cases: take a bit off both parting surfaces, reclamp, and line bore all journals back to standard. The shops which do this kiind fo think know how, and they are who you want to use.

I think that the cost of bearings with an oversized OD will cause your jaw to drop.