This valve tappet transmits motion from the camshaft lobe to the pushrod, opening the intake or exhaust valve at the correct timing interval. It sits between the camshaft and the pushrod within the engine’s valvetrain; any wear on the tappet face or stem reduces valve lift and disrupts cylinder timing. A worn tappet produces a ticking noise at idle and can cause a loss of engine power under load. The part is machined to the original stem diameter and face profile so that the pushrod seats squarely and the cam lobe contacts the tappet face at the correct angle. On installation, verify that the tappet rotates freely in its bore and that the pushrod cup is clean before seating the pushrod.