We check and adjust the valve clearances when repairing the cylinder head, when a resonant knock appears in the upper part of the engine.

Check and adjust at an engine coolant temperature below 60˚ С.

Remove the cylinder head cover

Проверка и регулировка зазоров клапанов Cummins ISF3.8Проверка и регулировка зазоров клапанов Cummins ISF3.8

We rotate the crankshaft and set the piston of the first cylinder to TDC of the compression stroke.

We check the clearance in the valve drive:

- the first intake;

- the first graduation;

- the second intake;

- the third graduation.

Проверка и регулировка зазоров клапанов Cummins ISF3.8

With a properly adjusted clearance, the feeler gauge passes between the rocker arm bridge and the rocker arm seat with little resistance.

Nominal clearance:

- inlet valve 0.280 - 0.381 mm

- outlet valve 0.530 - 0.630 mm

If the gap is less than the nominal, unscrew the lock nut and adjust it with the adjusting screw.

Tighten the lock nut and check the clearance again. Nominal clearance (when adjusting):

- inlet valve 0.33 mm

- outlet valve 0.58 mm

Tightening torque 24 Nm

We turn the crankshaft 360˚

We measure the clearances in the actuator of the remaining valves:

- second graduation;

- the third inlet;

- fourth graduation;

- the fourth inlet.

Adjust the clearances if necessary

We install all the details in reverse order.