measure piston ring gap in block?

[Jordan325iC]

Somewhat foolishly I removed the head from my troubled turbo engine, thinking the problem was the headgasket. Now I am having doubts, and am concerned that the rings might be at fault. Is there any way to measure or inspect pistons rings with the pistons and rings already installed?

Thanks

[jlevie]

There's a spec for ring groove dimensions and ring gap. But to check those the engine has to be torn down. Compression and leakdown number on an assembled engine will tell you a lot about the condition of the rings and cylinder bores.