main and rod bearing sizes

[kenp313]

This is probably a dumb question. I took my block and crank to machine shop to get them ready for my rebuild. The owner said that he is going to have to grind the mains and rod journals
" ten thousandths" my question is this: what kind of bearings do I need for that size. Is it as simple as ordering the clevite HD ones or is there some math to do. :help:

 

[duramaxzak]

So he's grinding the crank undersized .010"? I don't think it's recommended to have a Duramax crank ground undersized because of the nitrating process. Most guys buy a good used std. size crank or new one.

 

[kenp313]

Well

 

[duramaxzak]

Here's some info in this thread.

http://www.duramaxdiesels.com/forum/showthread.php?t=60967

 

[ikeG]

I have a lb7 crank that was ground. I plan to use it down the road. Can't be skeered. Lol.

 

[kenp313]

I can't afford to not be skeered

 

[ikeG]

Our consensus is that we will only use this crank in a competition engine that gets the oil changed all the time. And gets torn down for rebuild or a check over frequently. The idea is that without the crank being re hardened, any contamination/dirt/fragments in the oil will be forced into the crank material rather than the bearing, which is what would normally happen. At the same time, it also believed that the hardening process affects the crank much deeper than .010" so grinding that much off may not hurt at all. The other thread that zak linked talks about this some. Really, until someone does it, we wont know much for sure.

 

[kenp313]

Is getting it re- treated a hard thing to do or is it hard to find somewhere to do it

 

[ikeG]

By the time you pay to machine and re harden, you may be better off buying a new one. Especially with the peace of mind a new one gives.

 

[kenp313]

So no one dd a dmax with a ground crank ? What's the cost of a crank thats rtr.