Evo Camshaft End Play Measurement

There are a number of things that are critical to inspect, replace, or service while inside the cam compartment of an Evolution motor. Camshaft end play is one of these critical service points that needs to be scrutinized over.

If camshaft end play is set too tight, it can result in catastrophic failure and damage—especially if the result is a blown cam bearing.

If a camshaft is being reused, it may only be necessary to inspect cam end play. However, when a different cam or cam cover is being installed, setting camshaft end play will be in order. All Harley-Davidson factory service manuals for Evolution Big Twins have specific instructions for setting camshaft end play. Mike is set up to walk us through this process on our 1988 Heritage Softail.

Mike demonstrates removal and installation of the cam seal. The original seal is tapped out and a premium double-row replacement seal is installed. The new seal is started by hand before Mike taps it the rest of the way in with a deep socket.

Mike is installing a new S&S camshaft. Camshaft end play will definitely vary from the stock camshaft. From experience, Mike knows that a shim between .050″ & .065″ will be needed. He starts by trying a .060″ shim. The shim is installed on the end of the camshaft, followed by the stock spacer. Now, with a new cam cover gasket in position, Mike installs the cam cover and torques the retaining screws to factory specs. Next, Mike reaches through the lifter block openings and pulls outward on the camshaft. He can now reach in with feeler gauges to measure end play.

When the correct size shim is determined, the cam cover can be removed one last time in preparation for final assembly. Mike aligns the cam gear timing marks with the pinion gear and breather gear timing marks. The breather gear spacer is installed before Mike installs the cam cover and tightens the hardware to spec. Mike wraps up by installing the ignition rotor cup and sensor.

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