Those of you that are running Wiseco, Wiseco HD specifically, pistons...what PTW are you running for a 600-700whp goal? I've seen various clearances ranging from .002 all the way up to .005 when i did a search! I want to make sure I didn't go too small on mine since I can still technically get it re-machined(supposed to pick the block up from the machine shop tomorrow).

According to Wiseco HD specs that I found I set it up to .003 PTW. Can someone please confirm this is correct?? If not, what are you guys running?

Thanks in advance!

 

For that power level on a street driven car I think most competent machinist/builders will recommend a .004 clearance. For a car that only sees race gas/big boost .0045 or .005 could be done.

 

Thanks! Anyone else have any insight?

 

I'm having custom pistons built by them right now and the gentleman I spoke with told me .003 with the coating, which equals .004 from the actual aluminum material. He seemed like he know what he was talking about and he has built several 4G63 pistons.

 

Did you talk to Brian Nutter?

 

Honestly Chris with those I would not be afraid to go closer to .005" wall clearance. Maybe .0045" With the amount of boost and on pump gas you will be running, you want to be a tad looser.

 

I guess i'm glad I posted this up. ...although, I wish I had a couple weeks ago. I'm sure my machinist will be ecstatic to redo the block.

 

Wiseco runs tight PTW clearance, that's what they always say.

I used the non-HD and was told .0025" if I was going to do a 1500 mile break-in at low boost, and .0050" if I was going straight to high-boost with limited break-in. That was straight from Wiseco. I did .0025"

 

0.005 piston to wall clearance.
also, MAKE SURE YOU TWEEK THOSE OIL SQUIRTERS!!!
they will hit the bottom of the piston and you have to bend the squirter about half an inch to the center.

 

Thanks for the info guys. I ended up having the machine shop hone the block again to .0045. I'll be getting it back tomorrow. ...thanks for the info on the sqirters!