Contents: Camshafts ⇓ Pushers ⇓
Camshafts
1. To check the camshaft runout, you need two instrument prisms and a dial indicator. Typically, such a tool is available in metalworking workshops. therefore, if you suspect that its L is crooked, contact such a workshop. Compare the runout measurement result with Technical data. If the runout actually exceeds the permissible limit, the shaft must be replaced.
2. Inspect the shaft journals and the bores for them for wear and tear. If the bores are worn, you will have to replace the entire cylinder head with covers. Measure the diameter of the shaft journals with a micrometer (figure 21.2).
3. Check the wear of the camshaft:
- a) Inspect the cam lobe and cylindrical portions for scoring, uneven wear, pitting and chipping.
- 6) If the cam is badly worn, replace the shaft, but first try to find out the reason for the increased wear. Typically, wear on the cams is caused by poor lubrication or dirt in the oil. Check if there are any abrasive particles in the oil, if the oil pump is working properly, and if the oil channels are clogged.
- c) Measure the cam height with a micrometer (figure 21.3). If the wear of at least one cam exceeds the permissible limit, replace the shaft.
4. Measure the clearances in all shaft bearings using a "plastic feeler gauge" (figure 21.4, a, b). Compare the obtained results with Technical data. If the clearance in at least one bearing exceeds the permissible value, replace the shaft and measure the clearances again. If the clearances are still greater than specified, replace the cylinder head.
Pushers
5. Where mechanical ones are used (non-hydraulic) tappets, wipe off any oil from the tappets, mark the adjusting shims and remove the tappets together with the shims. Store the mount caps, pushrods and shims so that they can be reinstalled in their original locations later.
(The full text is on the website: «mazbook.ru»)
6. Inspect the working surfaces of the tappets for wear, pitting, scoring and signs of overheating (figure 21.6). As a rule, if even one of the tappets is defective, it is recommended to replace the entire set of tappets.
7. Measure the outside diameter of each tappet and the inside diameter of the corresponding bore. Determine the clearance by subtracting the tappet diameter from the bore diameter. Compare the obtained value with Technical data. If the clearance exceeds the permissible value, replace the tappets or cylinder head. Store hydraulic lifters upside down in a container of oil until assembly.