how to set up bearing clearances

[cjmatt]

I know how to check bearing clearances with a plastigage, but never knew if it was out of range, how you got it back to spec

lets say youre shooting for .0017 and its .001, how do you get that extra .0007 back

 

[Sean]

You can get many bearings in plus 1 or + 2 shells. so you take a normal undersize bearing and it comes up tight or loose. You get a plus or minus set of shells and you mix and match with the standards to get the desired clearances.

you can also alternatively Polish a crankshaft to size.

 

[cobrarwanab]

Other expensive option would be having the caps cut then hone the bearing bore to speck. Over/under size bearings is the easiest.

 

[Sean]

your better to have the bearing bore on the tight side of the spec. First the extra crush holds the bearing tighter in the bore. Second the tighter fit in the bore improves thermal transfer which helps to cool the bearing by increasing conductivity.

Better to cut the bore tight and use corrective bearings.

Other expensive option would be having the caps cut then hone the bearing bore to speck. Over/under size bearings is the easiest.

 

[QuickLX]

What Sean said here is correct. Cutting of the caps is usually only done if the bore was taken out too large by some bonehead thinking it would be easier than just going thru a couple sets of bearings. The crush on the bearing is what you are adjusting here anyway, not the clearance (well, you shouldn't be trying to adjust the clearances with the bore anyway).

Bearing Manufacturing Q.C. is not that great anymore and you'll find that a standard set of bearings will be all over the place. You are going to have to treat each bore individually.