How to Adjust the Valve Clearance of Cummins KTA-38 Engine

When the engine is adjusted, it must be in a cold state with water temperature lower than 60 C.

Remove the crankcase ventilation pipe, 16 bolt washer and vibration isolator, and remove the rocker arm chamber cover and gasket.

There are three rocker arms on each engine cylinder, the middle is the fuel injection rocker arm, and the rest are the valve rocker arms. Line+in, line+in, line+in, line+in, line+in, line+in, line+in, line+in. The engine runs counterclockwise when viewed from the flywheel end, and the ignition sequence is 1-5-3-6-2-4.

When adjusting the valve rocker arm and the fuel injection rocker arm, it must correspond to the correct crankshaft angular position. The accessory drives the pulley to rotate the crankshaft of the engine, and A, B and C on the pulley respectively indicate each adjustment position. When A, B or C on the pulley points to this position, adjust the corresponding rocker arm, as shown in the following figure. STC injector and valve adjustment sequence table

Adjust the cylinder number of the valve according to the position indicated by the pulley.

Forward winding symbol

A 3 5

B 6 3

C 2 6

A 4 2

B 1 4

C 5 1

It can go forward to a, adjustable 3 and adjustable 5.

Warning: Do not use the fan to turn the engine.

According to the order in the above table, you can adjust from any symbol. The following example illustrates the adjustment method by adjusting the rocker arm of 3-cylinder fuel injection from A. Turn A on the pulley clockwise to align the pointer with the gear housing cover.

Loosen the adjusting nut of the three-cylinder fuel injection rocker arm, tighten the adjusting screw until the gap disappears, and then tighten it once to realize the seat.

Loosen the adjusting screw of the fuel injector so that the STC tappet touches the upper cover of the fuel injector. To determine whether it is loose in place, it can be judged by whether the oil injection rocker arm can move.

Place the STC tappet adjustment tool on the STC tappet, turn the tool and insert the tool into one of the four holes on the tappet.

Move the tool with your fingers and lift the tappet to the upper limit position. Don't use too much force to avoid damaging the tappet.

Tighten the adjusting screw, while keeping the tappet at the upper limit position. The tightening torque is 0.6~0.7N.m Keep the adjusting screw still and tighten the lock nut. Nut tightening torque 6 1N.m When connecting the rod with special torque, the torque is 47 n.m. Remove the adjusting tool and wrench, etc. , and turn the fuel injection push rod by hand. If it can't turn, it means that the adjusting screw is too tight and should be readjusted.

Adjust the valve clearance according to the 5-cylinder valve selected by STC injector and valve adjustment table. Use 0.36 plug gauge to plug between the intake rocker arm and the pressure plate, or use 0.69 plug gauge to plug between the exhaust rocker arm and the pressure plate, respectively, and tighten the adjustment screw to 0.7N.m, and tighten the lock nut to 6 1N.m without turning the adjustment screw. Take out the plug gauge and adjust the clearance of the other valve. It shouldn't be difficult to take out the feeler gauge.

After adjusting the valve, turn the accessory drive pulley to B, and adjust the corresponding injector rocker arm and valve clearance in the column of "Adjustment Sequence Table". By analogy, let the crankshaft * * * turn twice, adjust 6 points, and adjust all rocker arms.

Check whether the tightening torque of all nuts is correct to avoid missing loose nuts. Replace the rocker arm chamber cover and gasket. If the gasket is not damaged, it can be reused. Tighten the bolts of rocker arm chamber cover according to the tightening sequence shown in the figure, and the torque is15n.m. If the gasket is damaged, replace it with a new one.