not sure if this topic has been cover before but i am installing some wiseco 84mm pistons in my Turbocharged b18c Darton sleeved block and on the wiseco website it says .004 piston to cylinder wall clearance for small blocks i don't know if this applies to imports as well. so just checking for wiseco pistons what clearance is best. block will be seeing upwards 30lbs of boost, mostly strip car.

thanks

 

If it's a strip oriented car and is going to be making a lot of power, go a little looser. I'd go with .005 or .006 myself

 

secondly is the bottom of the cylinder wall supposed to be slightly bigger than the top, because the machine shop that honed the block, when i got back the block the walls did not look that good(a bit rough) so i took it to another machine shop to check it. when the second machine shop checked it they said the clearance at the top was okay .004 but about 2 1/2 inches from the bottom of the sleeves the size of the cylinder was a little bit bigger.

 

gotta love those machine shops that cant do a simple bore an hone SMH.....

 

wow now that's scary. id do .004 for NA and .006 for turbo and other forced induction applications.

 

im make 3.5 for all motor and 4.5 turbo street car, race cars with alot of boost 5

 

well i just spoke with the second machinist and he said at the bottom is about .005 while at the top is .004 so would it be okay to just do the whole thing .005

 

yes go .005 you'll be good an even all the way down

 

how the hell do you get an extra .001 honing a block? is he using a flex hone lol

 

somewhere around .005 will be good for a strip car.

i just redid my engine after having an incident at .0035. i went up a little to .0045 and im good to go, making just shy of 500

 

lol! sounds like it.

 

ptw below than .004 and boosting more than 26psi will give u disaster..

 

.005 here, for 3 years street/strip. Whats odd is that I expected them to be loud and have excessive piston slap, they are quite as a mouse.. [manley pistons]