7.21.2. Check of a working gap of conrod bearings

1. Clear a back part of an insert and the place of its installation in a rod and a cover of a rod.
2. Establish inserts on the places.
3. One of methods which assumes existence of a micrometer for measurement of diameter of openings consists in establishing covers of conrod bearings together with an insert on rods and to screw them the required moment. Measure the internal diameter of each collected couple of inserts of bearings. Measure diameter of each conrod 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 conrod bearing the deformed plastic core is measured by a special template which is available in Plastigage set. The procedure for Plastigage use following.
5. Establish rods with inserts without lubricant on a bent shaft. 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 conrod 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 деформиро a bathing 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.