20 Engine 10-6 Cylinder Head, Camshaft and Balancer Shafts Model 2120 Tractor TM-4252 (Dec-70) 6. With camshaft gear in this position, install upper idler gear and tighten cap screw to specified torque. REMOVAL OF RIGHT-HAND BALANCER SHAFT Install cam followers, cylinder head, timing gear cover and fuel transfer pump. Remove lower idler gear 4 (fig. 10) (see group 25). Remove both cap screws 7 and thrust plate 6. Pull balancer shaft out of block. Run engine for some time at a specified load (see Specifications) and then retighten cylinder head cap screws to specified torque. Check valve clearance and readjust, if necessary.
REMOVAL OF LEFT-HAND BALANCER SHAFT BALANCER SHAFTS If still necessary, remove lower idler gear 4 (fig. 10). Remove oil pump gear 3 (see group 25). Remove both cap screws 7 and thrust plate 6. Pull balancer shaft out of cylinder block. REMOVAL NOTE: It is not necessary to remove the engine, when removing the balancer shafts. However, the front end of tractor must be removed to obtain access to front of engine ( see section 10, group 25). CAUTION: Take care when pulling out balancer shaft that neither the journals nor bushings located in cylinder head are damaged. Disconnect ground strap at negative pole of each battery.
REPAIR Measure twice each of the balancer shaft journals and bushing bores at right-angles to each other. Drain engine oil and remove oil pan. Measure thickness of each balancer shaft thrust plate, this plate determining the end play of each shaft. Remove timing gear cover. REPLACING A BALANCER SHAFT GEAR With the aid of a commercial press or puller, remove gear from balancer shaft. Set replacement gear onto shaft with the installation mark (see "c", fig. 11) facing upward. Press gear onto shaft until it is, within a tolerance (see Specifications), flush with face of balancer shaft. It is recommended that this tolerance be checked as it affects the end play of the balancer shaft. Fig.
10 Balancer Shafts, Installed spv *i* yv 1 Crankshaft gear 5 Right-hand balancer 2 Left-hand balancer shaft shaft gear 3 Oil pump gear 6 Thrust plate 4 Lower idler gear 7 Cap screws NOTE: To facilitate reassembly, mark on each balancer shaft and thrust plate from which side of the engine they have been removed (right or left-hand). Printed in Germany