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To check valve-to-piston clearance via the clay method, a lump of clay is laid into the valve notch area of the piston while the cylinder head is off. The head is then installed, along with the complete valvetrain, and the crank is rolled over through the overlap event. The head is then removed, and the valves' impression in the clay is examined and the thickness measured with a caliper to determine clearance. The clay may be sectioned with a razor blade for a full view.