h22 kid

the stock bore on a b16 is 81mm... whats the next size over? is it 81.5 mm or 82mm... i need to know because my gf's motor was honed to the next size over. needs new pistons.
thanks guys!

thumper64

Honda offers .010 oversized, but if you get Nippon or most any aftermarket ones, they'll be 81.5mm, although it's best to open it up and see. If it's 81.5, go to 82, if it's 82, you may be able to just use a ball hone and rering. You can't bore past 82, or at least that's the supposed limit. You never really know for sure what to do until you open the engine. I thought my engine was stock until I found 81.5mm forged pistons in it when I tore it apart. I bought 82mm pistons before that, but I had a cracked sleeve, so I got another block with a stock bore. So now I have 82mm pistons and would rather run 81.5 so I can leave the possibility to rebuild later.

thumper64

Someone may have even honed the walls and reringed the 81mm pistons. You may be at 81.5 and the walls could be gouged bad enough that honing out to 82 won't clean it up. Without tearing into it, it's impossible to say.

h22 kid

yo bro thank you so much! my buddy works at a machine shop here in ca and he said that the pistons were stock bore and needed to hone the block out a size over so im going to let him know that im going to go 81.5 mm so that way they hone is to spec. they said the blocks sleeves were good and no problem to hone. so thank you on your inquiry and problem solved lol

anothersickhatch

did you know that there is a difference between boring and honing? honing is supposed to clean up the cylinder walls for the current piston bore size so that new rings can break in properly. boring actually increases the piston size, which is why you need oversized pistons.

you can't hone a cylinder to a larger bore size, it has to be bored.

h22 kid

lol oops my mistake yeah there doing both. my bad