Well I am doing some engine work on a b18 a1. I am taking my block to a shop and I dont know what would work on it. If I bore each cylinder out .020, are there any pistons from another honda engine that would fit that, or would it be easier to find matchin pistons if I bore it .030. I definatly want to get this done, so if anyone is experienced in this field, please let me know.

 

OEM honda pistons for b series are only offered in standard bore and .25mm oversized which is about .01". If you want or need to go to .020" then you will want to run forged aftermarket. .020" is the most I'd overbore on a boost engine and .040" is the biggest I'd go all motor unless you want to sleeve the block.

 

FYI if you overbored it .020 then you would need to find 81.5mm pistons. Not hard to find but as KJ said oem were made in std(81mm) and oversized(81.25mm) only.

So if you wanted to run oem, you would have to overbore .010" (.25mm)

 

i have some OE ITR pistons oversized .25 if your interested. still packaged from honda. have pics too. PM me.-Greg

 

thanks for all the tips. and I pmed you Greg

 

what size are stock pistons on a b18a, how many mm's are they?

 

81mm is stock for all B-series engines

 

i thought the b20 was 84mm

 

You are Correct.

 

ok thanks, umm is it possible to fit b20 pistons in a b18 block with enough boring?