Checking cam wear
1. Remove the cylinder head cover.
2. Set the piston of the 1st cylinder to the TDC of the compression stroke.
3. Check cam wear on cylinder 1. To do this, place the indicator above the first rocker so that the indicator leg runs parallel to the axis of the rod and is located directly above the rod.
4. Set the indicator to zero, turn the crankshaft in the direction of normal rotation. After the readings stop changing, turn the crankshaft back until the arrow stops. The difference in readings is equal to the size of the cam.
5. Write down the readings and again set the piston of the 1st cylinder to the TDC of the compression stroke.
6. Move the indicator to another rocker of the 1st cylinder and repeat the measurements.
7. Repeat measurements for the remaining cylinders in accordance with the order of operation of the engine (see subsection 3.1.1).
8. Compare results with normative. If the decrease in the size of the cam due to wear exceeds the norm, then replace the camshaft.
Examination
1. Remove camshaft and clean. Check the condition of the necks. If there are signs of wear on the journals, then the camshaft bearings are also worn. In this case, the camshaft and bearings must be replaced.
2. If the necks are in satisfactory condition, then check their diameter in several places, determine the taper and ovality.
3. Check the inner diameter of the journal bearings, determine the clearance and compare with the standard. If the clearance is too high, replace the bearings (carried out in a car service).
4. Check the condition of the ignition distributor drive gear. If there are signs of severe wear, replace the camshaft.
5. Check the condition of the cams for chipping, scuffing and deep wear. Check the dimensions of the cams with a micrometer. If the cams are in satisfactory condition and the size is correct, then the camshaft can be used further.