You can read about valve adjustment below. There are some ways to valve adjustment, which you can learn. Such knowledge will have given you confidence by the engine repair and maintenance.
How to adjust the valves
Perhaps, you heard, that each cylinder has an exhaust and an intake valves. The combustible mixture intakes into the cylinder through the inlet valve, and exhaust exhausts from the cylinder through the exhaust valve. The gas distribution mechanism (or valve mechanism) provides the timely opening and closing of the valves.
Adjusting the valves is a very important process, which affects the life of the engine, so it needs to control correct valve gaps.
- What happens if there are small valve clearances? Small valve clearances will cause the valve seats to burn.
- What happens if there are large valve clearances? Large valve clearances will result in incomplete opening of the valves, which will affect engine power. Increased valve clearances can be recognized by the characteristic metal knock. Noise in the engine may indicate a timing problem.
- How often do valves need to be adjusted? Valves are regulated every 20-30 thousand km. in accordance with the manual for repair and maintenance of the car.
Valve Adjustment Sequence
Before the valves adjustment, set the cylinder piston in TDC (top dead center) to the compression stroke. In this position, both valves of the adjustable cylinder should be closed, and the rocker arms of these valves should swing freely within the gap.
Then slowly loosen the locknut on the adjusting screw or bolt. Using the adjusting screw, adjust the required clearance, and tighten the lock nut.
«Do not change the set valve clearance during puffing».
After this, check the thermal clearance again. Use a feeler gauge to check the clearance. The probe should pass into it with little effort, if such a sensation does not occur, but it passes very easily or very hard, you need to adjust the gap again.
To adjust the thermal clearance in other valves, the crankshaft must be turned half a turn. During adjustment, the operating order of the engine cylinders should be considered (1-3-4-2). Turn the crankshaft by the bolt securing the alternator drive pulley.
Check of clearances between levers and cams of a camshaft: 1 – probe; 2 – an adjusting bolt; 3 – a locknut of an adjusting bolt.
Valve Adjustment Procedure
Turn the crankshaft clockwise until the mark on the camshaft sprocket matches the mark on the bearing housing. In this position, the clearance is adjusted at the exhaust valve of the 4th cylinder and the intake valve of the 3rd cylinder (i.e. 8 and 6 cams).
Use a wrench to tighten the lever adjustment bolt, and at the same time use another wrench to loosen the lock nut. Set the required clearance with the adjusting bolt, tighten the lock nut. The probe should go into the gap with a slight resistance.
On the some engines thermal clearances are regulated by adjusting washers.
After adjusting the clearances in the valve mechanism, start the engine and listen carefully to it in various operating modes. When adjusting the valves, it should be noted that the valves must be properly ground, and the valve gaps should not exceed the permissible ones.