4032 forged piston to wall clearance?
Posted: March 6th, 2015, 9:50 pm
I'm having a 060 overbore done on a block(assuming sonic check says its ok) and i'm using autotec 4032 aluminum pistons which are 3.931 in diameter which they say is for a 3.935 bore. The one spec sheet I got with the pistons says I need .004 clearance on that specific piston and another sheet that talks about the 4032 aluminum says it should be .0025 to .0035 for a piston in that diameter range. I emailed racetec/autotec and they said anywhere between .0025 and .004 would be fine. I asked my machinist with just showing him the piston and telling him the material and he said he would usually do .003 or .0035. The build will forever be naturally aspirated. People in other forums that talk about 4032 all seem to use less than .004. So does this clearance need to be exact or am i overthinking this???