i have a question...im getting a set of wiseco 81.5mm pistons and i need to bore and hone my block..my question is..do i get it bored to exactly 81.5 mm which is 3.209 inches??? or if i want a larger ptw clearance,like .001 more, then do i get it bored to 3.210?? then which bore do i use for the equation to calculate ring gap?? 3.209 which is true 81.5mm or 3.210 which is .001 bigger to allow for expanison under heat... ex: bore x .006=ring gap



make it simpler...it calls for .0025 ptw clearance...do i bore to 3.209 or 3.211??

 

Ok, this was answered in your first post a few minutes ago, you take the piston size and add the clearance and that is what your finish bore should be.... it doesnt get any easier.

You cant bore anything until the pistons are in your hand and they have been measured and verified to match the spec sheet.

 

k gotcha thanks

 

Most people just give the machine shop their pistons along with the block and they will do the rest. Just be sure to tell them what P2W clearance you want when finished.

 

dont follow the spec..it all depends on wat ur doing....boost allmotor, nitrous..