Measure while engine is running
B&B's Blow-By Meter is the only effective way to measure piston ring sealing with the engine running. Blow-by is the pressure that builds up inside the engine crankcase and escapes though the breather valve cover. That is actually combustion gases that get out down the cylinder walls past the piston rings. Obviously, the more blow-by that comes out of the valve covers, the more problems that exist with the rings. This easy to read meter can be handheld to check the blow-by while the engines is in a car, boat, ect., or mounted directly in a dyno cell.