[dantm]

Hello this is not for a Porsche engine but I see a lot of expertise in this forum so I thought I would ask anyway.

I have an engine that was showing poor leakdown numbers when cold. The air is blowing by through the rings as we could hear it through the crankcase/oil tank.

We took everything apart and inspected the pistons/cylinders.

The factory tolerance for piston-to-cylinder gap is between 0.002 - 0.005". However, when measuring the cylinder bores and piston diameters we are finding 0.003 - 0.007". Would this be sufficient to cause poor leakdown in some of the cylinders?

Also for testing this correctly does it make sense to put up to 100 psi when the engine is cold and/or should we consider lower pressure? Would it make sense to create a test plate for the cylinders so that the heads are taken out of the equation?

Thank you all!