sz9182

I'm putting together parts for a LS/Vtec swap and I was just wondering which mm I should be buying. So far, my mind is set on 81mm for LS, but I feel kind of iffy. The website that I'm buying off of has a final sale policy, so I want to make sure that I'm buying the right one. Is 81mm correct for the head gasket and everything else? Or should I be getting a different size? Thanks

RyanA

My crystal ball is broken right now so I can't answer that question for you. However, after you take the block to a reputable machine shop, he will be able to tell you all of your answers....

CivicSpoon

81mm is the stock cylinder bore for the B18B, B16A, B16B, B18C1, & B18C5 engines. If the stock sleeves are fine and don't need to be honed, then 81mm is what you need to buy parts for. If the sleeves need to be honed, then you might need over sized stuff. So like RyanA said, take it to a machine shop and have them look over the block first, and then buy the specific parts that are needed.

slvrcvc93

well all honda motors are 81mm a long as they weren't bored out so if the motor is stock than you should be fine Cylinder Honing dosen't really take metal off the walls it just to get the glaze or any minor scaring on the cylinder walls off.

RyanA

While it's true that a lot of Honda engines will not require a bore job, there are times when you can't just throw a new set of pistons in. For example, I have a block in the shop that a guy in St Louis had built for a guy. He ran a hone in it just long enough to break the glaze and take out a few vertical scratches. He put in band new ITR pistons and new bearings. When it went in the car, it burned about a quart every 200 miles or so. I got the block as a trade in towards an engine I had built for my car. Upon disassembly, the piston rings literally had no tension on the cylinder walls. When a rod cap was removed, the piston/rod would just slide out on its own using only gravity.

Just to be safe, either get a machine shop to check the bore for you or find someone with a bore gauge to check for tapered or barrel shaped cylinders. Although it is harder and takes longer, you can also use inside telescoping gauges and a micrometer to check bore size in different places on the cylinder.