Model 2120 Tractor TM-4252 (Dec-70) Engine 20 Cylinder Head, Camshaft and Balancer Shafts 10-5 Replace gear of camshaft, if necessary. Position the new gear on camshaft so that timing mark "a" (fig. 7) faces away from camshaft. CAUTION: Support camshaft behind the front bearing journal, when pressing on gear. Press on gear until it is tight against the shoulder of camshaft. Replace tractormeter drive lug, if necessary. Install new drive lug in camshaft so that its slot faces away from the camshaft. Support camshaft at rear journal. ALWAYS replace cam followers when installing a new camshaft. INSTALLATION Install camshaft, observing the following: Fig, 8 - Measuring Camshaft End Play 1.
Coat camshaft with light, clean engine oil. Use special tool No. JD 254 to align timing mark "b" on the camshaft gear (fig. 9) between centers of crankshaft and camshaft by rotating the cam¬ shaft. 2. When installing, make sure that cam lobes do not damage bearing bores in block. 3. Rotate camshaft until cap screws attaching thrust plate can be installed and tighten them to specified torque. 4. Check camshaft end play (a new camshaft and a new thrust plate should add up to the proper end play). 5. With crankshaft at TDC and piston No. 1 (front) on compression stroke, adjust camshaft for valve timing. Fig. 9 - Timing Camshaft Gear by means of Special Tool No.
JD 254 b Timing mark Printed in Germany