to grind or polish, that is the question....

[dion914-6]

I'm rebuilding a 2.0L engine with a non-counterweighted crank. I inspected the crank, measured it up and found everything to be in good shape. The rod and mains are well within factory spec and the bearings all looked pretty good when removed. The rod bearing surfaces have a slight edge of roughness when doing the fingernail test, but I've seen much, much worse on my FV engines.

I took it up to the local machine shop (not a Porsche specialist) who is now telling me that the crank definitely needs to be ground based on his own 'fingernail' test. I'm not sure I want to believe him and feel like he may be trying to take advantage of me. I know it's hard to give advice when you guys can't see or feel the crank, but should I go pick my crank up and get a second opinion or just let him grind it?

Thanks,

Dion

[davidppp]

Check the mic dimensions.

If they are in spec ( probable) I'd definitely not grind it.

In fact I quite like clearnces at the top end of tolerance, provided the oiling is dealt with...even scores do not matter much IMHO..

Kind regards
David

[cnavarro]

If you did polish it, I would only let a Porsche shop do it, if it was me. You could then send the bearings to Calico Coatings and the amount they build up should be pretty close to what they take off the crank.

[dion914-6]

Thanks for the replys guys. I did mic the crank and it is right in the middle of the factory spec.

I think the prudent thing to do is get it back from this guy and ship it out to someone who knows what they are talking about.

Thanks,

Dion

[Nitrometano]

Just polished it.