piston clearance??

[Crispy Chicken]

machine work is done on my stage 2 block. pistons are at .010-inch clearance. shouldn't they be around 5 -7 thousandths. if i have to get new pistons made. where should i be. running stage 2 heads. engine should see around 30 psi. i have no idea how much expansion to expect and where it should be at. thank-you for advice

 

[49-blues]

I thought it should be about .001" for every inch of diameter of the piston, so a 4.00" bore should be about .004"-.005" as far I know but I would ask a competent stage2 engine builder,also type of piston material may matter. I'm using 4.00" JEs+ .005" clearance.

 

[gnxtc2]

You should bore the block slightly undersize, order your new pistons and hone the bores to size. The piston manufacturer includes the final bore size in the package. The manufacturer knows the expansion size of the piston.

Billy T.
gnxtc2@aol.com

 

[Alky V6]

I've heard of .010" used on high reving drag engines. It's a little hard on the rings with the added rock. It should be OK under full load, but I'm sure you're going to have some piston knock on cold startup. Just don't get too crazy with it until you have some heat in the engine. I wouldn't have set it up with that much clearance. .006" has worked good for me with JE.

 

[lazaris]

You can get the clearance down by .015 by going with a heavy skirt coating from Calico.

 

[Alky V6]

You can get the clearance down by .015 by going with a heavy skirt coating from Calico.

I'm sure you mean .0015".

 

[lazaris]

I'm sure you mean .0015".

I most certainly did.

 

[Crispy Chicken]

thanks a lot guys for the good info....