3.5.8. Camshaft and gas-distributing mechanism

Measurement of diameter of openings of bearings of the camshaft

Covers of bearings have to be fixed.


1. Install the camshaft in the centers of the lathe or enclose basic necks in two prisms and measure a shaft beating on an average neck.
2. Consider that the indication of the arrow indicator for one turn of the camshaft corresponds to the doubled value of a beating of a shaft. The beating should not exceed 0,02 mm. At excess of this value the camshaft is subject to replacement.

3. Check surfaces of cams on both sides. If no visible places of wear are revealed, it is necessary to measure height of cams a caliper and to compare results of measurements to data of the table of adjustments and the sizes. 
4. On the diesel engine the axial side play cannot be checked in the usual way as it is impossible to insert the probe. The axial side play on this engine is calculated by the following sprsoby:

5. Measure the size "A" from the inside of a cover of the bearing and write down value.
Measure and write down the size "B", that is width of a basic neck of the camshaft.
6. Subtract the size "B" from the size "A". The difference of these sizes is an axial side play of the camshaft which should not exceed values of 0,04 mm. Otherwise it is necessary to replace the camshaft or a cover of the bearing.
7. Check degree of wear of basic necks of the camshaft.
8. With wear of necks further works are not required to be performed. In this case it is also necessary to check openings under bearings in a head of cylinders which can be also developed.
9. For definition of side plays of bearings of the camshaft put on covers of bearings according to their numbering and tighten till the ordered moment. Make measurement of bearings (see rice. Measurement of diameter of openings of bearings of the camshaft) in the directions "A" and "B" and in places "1" and "2". Write down results of measurements. After that measure by a micrometer diameter of necks of bearings. The difference of measurements on the separate bearing is also its side play. The difference between the sizes "A" and "B" is not roundness, and the difference between measurements "1" and "2" gives conicity. 
10. Carefully check both gear belts. Belts with the hardened back party or the cracked surfaces which are broken off or the cracked teeths are subject to replacement. Check teeths of belt pulleys. If teeths are damaged, belt pulleys, and also the corresponding gear belt are replaced. The tension roller has to turn freely in the fastening without jammings.