3.5.17. Choice of bearings

Marking of group of the sizes of a radical neck of the bearing of a bent shaft of the diesel engine of 1,7 l

Place of drawing marking of diameter of an opening of bearings of the diesel engine of 1,7 l

Diesel engine of 1,7 l

Apply 4 various inserts which are designated by a color tag at an end face to the choice of a working gap of bearings. Color of a tag designates thickness of an insert and consistently increases depending on color: green, brown, black or blue.

If it is necessary to replace a bearing insert, at first check and make record of a tag of the identification located on cranked to a shaft adjacent to each radical neck of the bearing.

Write down the main markings of identification of the size of an opening of the bearing which is put on the lower interfaced surface of a back part of the block of cylinders of the engine.

According to a code of an opening of the bearing and a code of a neck of a bent shaft choose a new insert of the radical bearing, using the following table. Codes of a bent shaft are given on the left side, codes of openings of bearings in the top part. The type of the bearing is chosen on crossing of two lines.

Other engines

Use as standard, and with the reduced size of radical bearings of a bent shaft is possible. The required size of the bearing can be determined after measurement of a neck of a bent shaft.

Check of a working gap of the bearing

1. Clear a back part of an insert and the place of its installation in the block of cylinders and covers of radical bearings.
2. Establish inserts on the places, at the same time the ledge on an insert has to be combined with a groove on a cover.
3. One of methods which assumes existence of a micrometer for measurement of diameter of openings consists in installing covers of radical bearings together with an insert on the block of cylinders and to screw them the required moment. Measure the internal diameter of each collected couple of inserts of bearings. Measure diameter of each radical neck of a bent shaft. Subtract the corresponding diameter of a radical neck of a bent shaft from the measured diameter of the bearing.
4. The second (and more exact) the method consists in using the product known as Plastigage. It is a round plastic core which contracts between an insert and a neck of a bent shaft. After removal of a cover of the radical bearing the deformed plastic core is measured by a special template which is available in Plastigage set. The procedure for Plastigage use following.
5. On the inserts installed in the block of cylinders establish a bent shaft without lubricant. Necks of a bent shaft and inserts have to be absolutely pure and dry.
6. Cut off several pieces of a plastic core of Plastigage (they have to be slightly shorter, than width of the main bearings) and establish on each neck of a bent shaft.
7. Establish covers with the lower inserts and tighten fastening bolts the required moment. In the course of measurement of a gap by Plastigage method do not rotate a bent shaft.
8. Unscrew a cover of fastening of an insert, remove it and apply a large-scale ruler to the deformed plastic core. Comparing width of the deformed plastic core to control width on a large-scale ruler, determine gap size.
9. In conclusion carefully clear Plastigage traces – material from inserts and a bent shaft.