The gap in the valve mechanism should guarantee a tight fit of the valve to the seat when the rod is extended from heating and in case of head settlement in the seat due to chamfer wear
Gap adjustment is carried out on a cold engine no earlier than 30 minutes after it stops, while the fuel supply is turned off and the car is braked with a parking brake.
The gaps are simultaneously adjusted on two heads in pairs in the order of operation of the engine cylinders.
First, the crankshaft is rotated until the notch on the flywheel matches.
First, the engine crankshaft is turned and set to a position characterized by turning it in the direction of rotation by 60 ° relative to the start of fuel injection in the first cylinder.
In this position, the valves of the adjustable cylinders (1 and 5) are closed (the rods turn freely).
To adjust the valves following the order of operation of the cylinders, turn the crankshaft in the direction of rotation each time by 180 °.
Cylinder order 1-5-4-2-6-3-7-8.
If you turn the flywheel from below by the holes in the flywheel, then first turn from TDC towards the location of the batteries by two holes in the flywheel.
Turn the flywheel clockwise when viewed from the front of the engine (counterclockwise when viewed from the rear of the engine). And adjust the gaps in the 1st and 5th cylinders.
Then through 6 holes in the flywheel, the next two cylinders are 4 and 2nd, and so on. Since there are 12 equally spaced holes on the flywheel for scrolling, then 6 holes just correspond to 180 ° of rotation of the crankshaft.
Before checking the clearance, tighten the nuts securing the rocker arms and the bolts securing the head; at the same time, in order to exclude possible deformation of the rods, it is recommended to increase the gap by unscrewing the adjusting screws from the rocker arms.
The required clearance is set with a feeler gauge 0.30 mm thick for the intake and 0.40 mm for the exhaust valves.
Holding the locknut, turn the screw with a screwdriver so that the probe moves in the gap with a noticeable force.
After that, while holding the screw with a screwdriver, tighten the lock nut, check the gap again with a feeler gauge and, without removing it and turning the rod, make sure that it rotates freely.