Got the block hot tanked, getting ready to drop in the crank and check my bearing clearances. I'm not too happy with the condition of the block's matching main caps, they're a little rusty and pitted from sitting in the previous owners basement too long. So I'm going to swap the main caps from my old b18a1 over...in theory it should work fine. The bearing codes on the old block were BBBBB all across the board, and the new block lists CBBBC. So if I only retain the outside 2 caps (#'s 1 and 5) everything should still match up, correct?

 

i wouldn't see why not but you gotta remember that all this stuff is used, so it's subjected to not being perfect anymore, so plastigaging is the way to go i'd say.

 

Already on it Plastigauge is my friend when it comes to standard size bearings and swapping mains. I'll find out in about 10 minutes what they spec out to.

 

Ok...here's the outcome...almost all 5 journals spec out to 0.001in. or 0.025mm. Number 3 journal was a tad looser, but not by much (it's supposed to be looser than #'s 1,2,4,&5).I've never had a motor spec out this tight before...should I just say ---- it and order new bearings, or assemble it tight? What would be the downside to running tight...other than spinning a bearing? :P

 

im not 100% sure but i think if you switch main caps from a different motor they wont be 100% round anymore and have to get the mains honed . i would call a machine shop to check on this. if im wrong, you only waste a phone call and 5 minutes of your time.

 

clearance specs are what they are to ensure proper lubrication.

 

Yeah, I just cross-referenced the number/letter combo's again on the crank and the block...and according to the bearing sizes themselves they should have about 0.030-0.035mm clearance. I'm going to clean up the original main caps and try them and see if it'll make a difference. Only original ones I tried spec'ing out were #'s 1 and 5...and they were actually the best numbers.
I'm aware of that...I just want to know the downsides to running it tight. Technicly it's still within spec except for #3, just a hair too close to the limit for me.

 

That's why you don't move mains unless your having the block line honed after replaceing them.

 

Well, I was honestly hoping that since they were stamped with the same coding for the mains that I tried to use that they would work just fine. On a rough measurement before I tried them they seemed like the same bore size, but I'm going to plastigauge it again today with the original mains and see where it sits.

 

And the results are in...originals ftw! The originals were almost 1 thous. larger diameter than the other one's I tried. New plastiguage results were 0.0015" all across the board, except for the bastard #3 main bearing...still sitting at 0.001. Time to go to Honda and order up a smaller size bearing. :P