855499 Mercruiser CLAMP ASSY.-OIL COOLER (4.2L)

Illustration 1 g01106134
Engine design (A) Inlet (B) ExhaustNote: Valve lash is measured between the rocker arm and the top of the valve. All measurements and adjustments must be made with the engine stopped and the valves fully closed.Valve Lash Check
An adjustment is NOT NECESSARY if the measurement of the valve lash is in the acceptable range in Table 1.
Table 1
   Inlet Valves    Exhaust Valves    
Valve Lash (Stopped Engine)     0.38 0.08 mm
(0.015 0.003 inch)    
0.64 0.08 mm
(0.025 0.003 inch)    
TC Compression Stroke     1-2-4     1-3-5    
TC Exhaust Stroke (1)     3-5-6     2-4-6    
Firing Order     1-5-3-6-2-4 (2)    
( 1 ) 360° from TC compression stroke
( 2 ) The No. 1 cylinder is at the front of the engine.If the measurement is not within this range, an adjustment is necessary. Refer to "Valve Lash Adjustment" for the proper procedure.Valve Lash Adjustment
Use the following procedure to adjust the valve lash:
Put the No. 1 piston at the top center position on the compression stroke. Refer to Testing and Adjusting, "Finding Top Center Position for No. 1 Piston".
Table 2
TC Compression Stroke    Inlet Valves    Exhaust Valves    
Valve Lash    
0.38 0.08 mm
(0.015 0.003 inch)    
0.64 0.08 mm
(0.025 0.003 inch)    
Cylinders     1-2-4     1-3-5    
Adjust the valve lash according to Table 2.
Lightly tap the rocker arm with a soft mallet. This will ensure that the lifter roller seats against the camshaft's base circle.
Loosen the adjustment locknut.
Place the appropriate feeler gauge between rocker arm and the top of the valve. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the top of the valve. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.
Tighten the adjustment locknut to a torque of 29 7 N m (21 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.
Remove the timing bolt and turn the flywheel by 360 degrees in the direction of engine rotation. This will put the No. 6 piston at the top center position on the compression stroke. Install the timing bolt in the flywheel.
Table 3
TC Exhaust Stroke    Inlet Valves    Exhaust Valves    
Valve Lash    
0.38 0.08 mm
(0.015 0.003 inch)    
0.64 0.08 mm
(0.025 0.003 inch)    
Cylinders     3-5-6     2-4-6    
Adjust the valve lash according to Table 3.
Lightly tap the rocker arm with a soft mallet. This will ensure that the lifter roller seats against the camshaft's base circle.
Loosen the adjustment locknut.
Place the appropriate feeler gauge between rocker arm and the top of the valve. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the pushrod. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.
Tighten the adjustment locknut to a torque of 29 7 N m (21 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.
Remove the timing bolt from the flywheel after all adjustments to the valve lash have been made. Reinstall the timing cover.