20 Engine 10-4 Cylinder Head, Camshaft and Balancer Shafts Model 2120 Tractor TM-4252 (Dec-70) Insert timing screw into the flywheel housing hole. Rock the flywheel until screw slides into hole in flywheel rim (flywheel will then be exactly in TDC position). CAMSHAFT REMOVAL To remove the camshaft and related parts it is not necessary to remove the engine. However, the front of the tractor must be separated to get access to the front of engine (see section 10, group 25). Adjust clearance of the exhaust valves of cylinders Nos. 1 and 3, and the intake valves of cylinders Nos. 1 and 2. Disconnect both battery ground straps. Remove cylinder head, timing gear housing and fuel transfer pump.
Remove all push rods and cam followers and iden¬ tify them to facilitate replacement in their original bores. NOTE: Be careful that cams do not damage the bearing surfaces in bores. REPAIR Fig. 6 Adjusting Clearance of the Intake Valve of Cylinder No. 1 Measure each of the three bearing journals of the camshaft as well as the corresponding bores in two opposing planes. 1 Feeler gauge 3 Adjusting screw of 2 Adjusting screw of exhaust valve intake valve Measure thickness of thrust plate since this thrust plate determines camshaft end play. Adjust the valve clearance, using a feeler gauge (see fig. 6 and Specifications).
Pull timing screw out of flywheel bore, turn crank¬ shaft one complete revolution (=360°) and insert timing screw again into flywheel bore. Adjust clearance of exhaust valves of cylinders Nos. 2 and 4 and inlet valves of cylinders Nos. 3 and 4 (see Specifications). NOTE: After the engine has run for some time on a specified load (see Specifications), tighten cylin¬ der head screws to specified torque. Check clearance of all valves and readjust, if necessary. 40169 Fig. 7 - Pressing Gear on Camshaft a Timing mark up Printed in Germany