B17 rebuild clearances....

I have a B17A block, and PCT OS pistons at the machine shop.

I was asked to find the clearances for the piston to cylinder wall, rod bearings and main bearings. I was told that the stock numbers in the service manual aren’t best for a more serious build up.

Service manual states:

Main bearing to journal oil clearance:
No. 1, 2, 4, 5 = 0.024-0.042mm
No. 3 = 0.030-0.038mm

Connecting rod bearing to journal oil clearance:

Piston to cylinder clearance:

My machinist is recommending Clevite 77 bearings. His book doesn’t list the B17A, will the B16A2 bearings work? I’m 95% sure that they will.

What specs did you guys use, my searches didn’t turn up much. Probably using the wrong words.


well looks like the main bearings and connecting rod bearings have the same Honda part numbers as the B16A2, so that answers part of my question.

So no one knows what tolerances were used when rebuilding their motor?

don’t tolerate any more than you have to

so picking a mid point in the recommended tolerances would be best?