Belarus 80.1 Operation Manual page 312

6.4.4.13 Operation 44. Check / adjustments of gaps between valves and rocker
arms of the engine
Check and, if necessary, adjust the gaps between valves and rocker arms every
500 hours of operation, as well as after removing cylinder head, tightening bolts attaching
cylinder head and in case valves start making knocking noise.
The gap between face of rocker arm and face of valve stem, when checked on a
cold engine D-243/D-243С (coolant and oil temperature shall not exceed 60  С) shall
make:
intake valves and exhaust valves:
When adjusting, set the gap between face of valve stem and face of rocker arm on
a cold engine D-243/D-243С as follows:
intake valves and exhaust valves: 0.25
Adjust in the following order:
- remove the caps of cylinder head covers and check the tightening of bolts and
nuts of rocker arm shaft bracket's fastening;
- turn the crankshaft through until valves in the first cylinder are blocked (the intake
valve of the first cylinder starts opening, and the exhaust valve has finished its closing) and
adjust gaps in the fourth, sixth, seventh and eighth valves (counting from the fan), then
turn the crankshaft by one revolution by installing a shut-off in the fourth cylinder, and ad-
just the gaps in the first, second, third and fifth valves.
To adjust the gap, release, in accordance with Figure 6.4.36, locknut 3 of adjusting
screw 1 on the rocker arm of adjustable valve, and by turning the screw set the necessary
gap according to clearance gauge 2 between rocker arm face and valve stem face. After
setting the gap, tighten the nut. After finishing to adjust the gap in the valves, place back
the cap of cylinder head cover.
1 – adjusting screw; 2 – clearance gauge; 3 – locknut.
Figure 6.4.36 – Adjustment of gaps in valves

, 0 10
mm.
, 0 25

, 0 05
mm.
-0,05
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80-0000010B OM