Model 2120 Tractor TM-4252 (Dec-70) Engine 20 Cylinder Head, Camshaft and Balancer Shafts 10-3 Cylinder Head Gradually tighten cylinder head cap screws evenly, following the sequence outlined in fig. 4 and final¬ ly tighten to specified torque. Install push rods into their original bores according to the marks made on removal. Place a valve cap on each stem and make certain that they turn freely. Apply clean oil to valve stems and install the valves in the same guide ports from which they were re¬ moved. Move valves up and down several times to ascertain that they slide freely and are properly seated. When assembling observe the following: ROCKER ARM SHAFT ASSEMBLY 1. Always use new keepers.
2. When replacing valve springs, make sure that the end contacting the cylinder head is properly seated. 3. After the valves are installed, give the stems two or three taps with a rubber or nylon hammer, so that the parts will seat properly, resp. to ensure the proper positioning of the keepers. INSTALLATION CYLINDER HEAD Use a new cylinder head gasket, coated with a uniform thin layer of "PERMATEX Type 3", "TEROSON - Atmosit", "COLLEX- Aviation'", or "HERMETIC-Hermalex" on both sides and place it on the cylinder block. Fig. 5 - Tightening Rocker Arm Shaft Assembly 1 Cap screws 2 Rocker arm shaft assembly CAUTION: Use hardened flat steel washers under all cylinder head cap screws.
Install rocker arm shaft assembly on cylinder head so that the lubrication holes are at the flywheel end. Turn the rocker arm shaft so that these holes are facing down. Tighten cap screws to specified torque (see fig. 5). ADJUSTING VALVE CLEARANCE The valve clearance can be adjusted with the engine cold or warm. Turn crankshaft to the right (seen from the radiator) until the No. 1 piston (front) reaches top dead center (TDC) of its compression stroke; CAUTION: not the exhaust stroke. Fig. 4 - Correct Sequence for Tightening Cylinder Head Cap Screws Printed in Germany