Piston Clearance

[fgordon]

Last summer I had a local engine builder overhaul my engine and install forged pistons and a cam. Today I opened the engine after about 350 miles to install ported heads. I discovered that I had almost 35 thousands piston to cylinder wall clearance. This seems excessive to me. Does anyone know what the measurements should be?

 

[750H.P.V6]

I'm not sure how you're measuring but the piston to wall clearance should be in the neighborhood of .005"

Neal

Last summer I had a local engine builder overhaul my engine and install forged pistons and a cam. Today I opened the engine after about 350 miles to install ported heads. I discovered that I had almost 35 thousands piston to cylinder wall clearance. This seems excessive to me. Does anyone know what the measurements should be?

 

[S2V6RACER]

The measurement is not taken at the top of the piston.

 

[fgordon]

The measurement is not taken at the top of the piston.

Where is it taken.

 

[750H.P.V6]

Typically the piston dia. is measured 90 degrees to the wristpin approx 1/2" to 3/4 " from the bottom of the skirt. This will vary somewhat from application to application and by manufacturer.

Neal