I am probably going to have my stock crank turned during my rebuild which I believe means they will take material off of it to make it all smooth again. Now when I look at bearings they list them as stock or .10, .20, .001, etc.. UNDERSIZED. Does that mean they are actually bigger to make up for the undersized crank, or are the bearings themselves undersized??


Thanks.

 

No your first inclination is right. The bearings are oversized to make up for the corresponding reduction in size in the crank.

 

Alright cool. So they are simply talking about the crank being undersized. Makes sense. Thanks.

 

Ok the problem is did you spin a bearing? If so I'd just get a new crank, if not you don't need to turn it. You can get away with just polishing the journals. People don't realize that the labor to just turn a crank is just not needed today unless it's an expensive aftermarket piece.

Bret

 

No it just blew a headgasket. So if the crank itself is fine there is no need for it to be turned?? If the journals are polished will I need different bearings??

 

New bearings need to be matched to the crank after it is polished.

 

Bearings are undersized for the material you take off, if you are having to turn the crank, you will surely have to get that block line bored and you will need a + size bearing to make up the difference you took off to make the things true again. Personally I wont use a block or crank that needs to be turned, if it is a high performance application you have a greater chance of spinning a bearing with a line bored block/turned crank. I say get a new crank atleast.

 

Yeah all you need is to polish the crank then. That just takes new stock size bearings.

As for line/bore line honed blocks, as long as it done CORRECTLY it's actually better than stock. How do you think you install 4 bolt main caps?

Bret

 

Alright thanks Bret. I think I learn new things every time you post.