3.11.6. Camshaft drive chain

Wash out a chain in kerosene, and then check a condition of its links. On rollers and on cheeks chips, cracks and other damages are not allowed.
During the operation of the engine the chain is extended. It is considered efficient if the natyazhitel provides a tension i.e. if the chain was extended no more, than on 4 mm.

Fig. 3-58. Device 67.7824.9521 for check of wear (extract) of a chain: 1 — a roller; 2 — an adjusting nut; 3 — a counterbalance

Check an extract of a chain on adaptation 67.7824.9521 (fig. 3-58) having two step rollers 1 which the chain is put on. By means of a counterbalance the 3rd chain stretches by effort of 294 N (30 kgfs) or 147 N
(15 kgfs). The adjusting nut 2 provides parallelism of an axis of a counterbalance concerning adaptation basis.

Fig. 3-59. Scheme of check of wear (extract) of a chain: 1 — rollers

Stretch a chain by effort of 294 N (30 kgfs), having put a counterbalance in extreme right position, then reduce effort to 147 N (15 kgfs), having shifted a counterbalance in extreme left situation. Repeat once again both operations and determine a chain extract by distance of L (fig. 3-59) between axes of rollers. Having measured by a caliper distance between diameters of d of rollers and having added to it diameter of d, receive distance of L between axes rollers.
For a new chain the distance of L between axes rollers makes 495,3+0,5+0,1 mm.
If the chain was extended to 499,5 mm it it is necessary to replace. Before installation on the engine oil a chain engine.