20 Engine 10-10 Cylinder Head, Camshaft and Balancer Shafts Model 2120 Tractor TM-4252 (Dec-70) CYLINDER HEAD - Continued Dimensions of Valve lift (clearance adjusted) New Parts Wear Tolerance Intake valve 0.460 to 0.490 in 11.7 to 12.5 mm 0.430 in 10.9 mm Exhaust valve 0.456 to 0.482 in 11.6 to 12.2 mm 0.426 in 10.8 mm Rocker arm shaft dia 0.7869 to 0.7879 in 19.987 to 20.013 mm 0.002 in 0.05 mm Rocker arm bore dia 0.790 to 0.792 in 20.066 to 20.117 mm 0.002 in 0.05 mm Rocker arm shaft spring Spring tension at a length of 1.813 in (46 mm) 4 to 6 lbs 1.8 to 2.7 kg Valve springs 2 12& _n Spring free length approx 54 mm Spring tension at a length of 1.813 in (= 46 mm) Valves closed 54 to 62 lbs 24.2 to 27.8 kg Spring tension at a length of 1.359 in (= 34.5 mm) Valves opened 133 to 153 lbs 60.5 to 69.5 kg Dia.
of camshaft bearing journal ................. 2.1997 to 2.2007 in 55.872 to 55.898 mm Retightening cylinder head cap screws Run engine for half an hour at rated speed = 2500 Loosen screws by 5° to 10° and tighten to the specified torque. rpm. CAMSHAFT 0.001 in 0.025 mm Dia. of camshaft bearing bores in cylinder block 2.2042 to 2.2052 in 55.987 to 56.012 mm Clearance 0.0035 to 0.0055 in 0.09 to 0.14 mm 0.007 in 0.178 mm End play 0.0025 to 0.0085 in 0.06 to 0.22 mm 0.015 in 0.381 mm Thickness of thrust plate 0.156 to 0.158 in 3.96 to 4.01 mm 0.005 in 0.13 mm Printed in Germany