OK I know that forged pistons run more clearance, but I am measuring .005 for my JE pistons. Does that sound like a lot? The directions say max of .036 but that you can add another .003 for turbo charged applications which puts me within spec. It just sounds like a lot. Thoghs would be appreciated.

 

The necessary piston to wall clearance is influenced by application, hp, alloy, etc. Basically, the more heat the piston will see, the more it will expand, therefore more clearance will be necessary. For example, a piston for a high horsepower endurance engine will require more clearance than a mild street engine. I believe JE's off-the-shelf pistons are made of 2618 alloy...in this case about .0035- to .004" should be safe. How much hp and boost do you have in mind? Will this be a daily driven street car or race car?