Camshaft Gear/Sprocket: Service and Repair

Fig. 23 Camshaft gear removal:

When necessary to install a new camshaft gear, the camshaft will have to be removed as the gear is a pressed fit on the shaft. The camshaft is held in position by a thrust plate which is fastened to the crankcase by two capscrews which are accessible through two holes in the gear web.
Use an arbor press to remove the gear and when doing so, a suitable sleeve, Fig. 23, should be employed to support the gear properly on its steel hub. If old thrust plate is to be used, position it so the key won't cause damage during removal.

Fig. 24 Checking camshaft endplay:

Before installing a new gear, assemble the key, then the spacer with it's chamfered end facing the journal radius. Lubricate the thrust plate, and install it to the shaft. Press the gear on until it bottoms against the spacer. The correct camshaft to thrust plate clearance is .003 inch to .008 inch Fig. 24.
The crankshaft gear can be removed by utilizing the two tapped holes in conjunction with a gear puller.

Fig. 25 Valve timing marks:

Fig. 26 Checking timing gear backlash:

Fig. 27 Checking timing gear runout:

When the timing gears are installed, be sure the punch-marks on both gears are in mesh, Fig. 25. Backlash between the gears should be from .004 inch to .006 inch, Fig. 26. Check the runout of the gears, Fig. 27, and if the camshaft gear runout exceeds .004 inch or the crank gear runout is in excess of .003 inch, remove the gear (or gears) and examine for burrs, dirt or some other fault which may cause the runout. If these conditions are not the cause, replace the gear (or gears).