The clearances between the rocker arms and valves are adjusted on a cold engine, with the cylinder head fastening nuts and the nuts fastening the racks of the rocker arm axles are tightened to the required torque
The adjustment of the thermal gap between the valves and rocker arms is performed when repairing the cylinder head.
It is necessary to adjust the valve clearances after replacing the valve stem seals.
The same when there is a knock in the area of the valve cover.
With an increased gap, a characteristic sonorous metallic sound appears.
With a small gap between the valves and rocker arms, the engine will seem to be “clamped”, or they also say “dumb”.
This will reduce its power and throttle response, increased wear of the valve mechanism.
Adjustment is carried out on a cold engine.
The engine is considered conditionally cold when its temperature equals the ambient temperature.
To make it easier to scroll the crankshaft, you need to unscrew the candles.
It is easier to navigate when scrolling the crankshaft if the cover of the distributor is open.
On the body of the distributor with a felt-tip pen, we make marks that correspond to the position of the pistons at TDC when the distributor slider approaches each contact of the distributor cap.
Remove the carburetor air filter housing for this:
Loosen the clamp with a screwdriver and remove the crankcase exhaust hose.
We “snap off” five clips, and remove the cover of the air filter housing, take out the filter element.
Loosen the clamp with a screwdriver and remove the corrugated air intake hose
With a screwdriver, we bend the antennae of the lock washers, and with a 10 key we unscrew the three nuts
Remove the air filter housing
Disconnect the crankcase exhaust pipe
Disconnect the vacuum regulator hose of the ignition distributor sensor
Using a 10 socket wrench, we unscrew the six bolts of the block head cover
Remove the cover
Removing the seal thread pad.
Set the piston of the first cylinder to TDC.
To do this, turn the crankshaft so that the third mark on the pulley aligns with the lug on the cover of the timing sprockets.
After that, remove the distributor cap and check that the slider is in the contact position of the 1st cylinder.
If not, rotate the crankshaft one revolution. Both valves of the first cylinder must be closed.
With a 14 key, we release the lock nut of the adjusting screw and unscrew the adjusting screw by one or two turns.
Insert a probe between the valve stem and the rocker.
We turn the adjusting screw until the probe moves in the gap with little effort.
Having set the gap, hold the adjusting screw and tighten the locknut and check the gap again.
We adjust the clearances of both valves of the first cylinder.
Then with a special key behind the ratchet:
Turn the crankshaft half a turn (180°) and adjust the clearances in the valve drive of the 2nd cylinder.
Turn the crankshaft another half turn (180°) and adjust the clearances in the valve drive of the 4th cylinder.
Turn the crankshaft another half turn (180°) and adjust the clearances in the valve drive of the 3rd cylinder.
The value of the gaps in the valve drive:
|
Number cylinder |
Valve |
Value gap, mm
|
|---|---|---|
|
1 |
Inlet Graduation |
0.40 - 0.45 0.35 - 0.40 |
|
2 |
Inlet Graduation |
0.40 - 0.45 0.40 - 0.45 |
|
3 |
Inlet Graduation |
0.40 - 0.45 0.40 - 0.45 |
|
4 |
Inlet Graduation |
0.40 - 0.45 0.35 - 0.40 |
After adjusting the valves, you need to start the engine and after warming up, make a test drive.
In case of unsatisfactory operation of the valve mechanism, repeat the clearance check.