Okay i've been told by so many people that you need to replace your pistons when doing an ls vtec because of the valve relief, which would make sense, but if that were true then you wouldn't be able to turbo an lsvtec bc the low compression pistons aren't domed and would hit your valves. This is just what i've been told. But my friend is doing an ls vtec with b18b block and b16a2 head. I did search but didn't find what i needed.

 

No..you do not need to replace the pistons.Ive done numerous ls/vtec's and never HAD to swap out pistons.I havent tried the stock pistnos with huge aftermarket cams..but with anything up to CTR's ive had no clearance problems.The valve reliefs on some b20 pistnos are too small..so on those you either have to swap out the pistons with aftermarket(since there are no factory replacement) or take a die grinder or dremel to the stock pistons and open up the reliefs,than clay the engine to check clearance..and remove more material from the reliefs if needed.

 

You don't have to replace the pistons however many people do because they are building the motor for all motor applications and want higher compression.

 

You don't have to like everyone is mentioning, but alot of people recommend it because most people get ls bottoms ends that have like 150K on them and decide to put a vtec head on them and rev the **** out of them. Then they wonder why the motor only lasted a few weeks. But it has more to do with it then just pistons.