ef5af8e6 Pistons and rods

Piston and rod

1 – lock ring

2 – piston finger

3 – an arrow on a piston head

4 – piston

5 – rod

6 – rod tag


For fastening of the lower head of a rod it is necessary to use new bolts and nuts.


1. Remove a head of the block of cylinders, the oil pallet and a pipe of an oil receiver.
2. On all models if there is a deposit in the top part of the cylinder, remove it with a scraper from soft material. Existence of a step in the top part of the cylinder testifies to excessive wear of the cylinder and need of boring of the cylinder of the engine.
3. Check a side gap of all lower heads of a rod.
4. Using the hammer and a center punch or paint, note the provision of a cover of the lower head of a rod and number of the cylinder.
5. Turn a bent shaft so that pistons of the first and fourth cylinders were installed in the lower dead point.
6. Unscrew bolts of fastening of a cover of the lower head of a rod of the first cylinder. Remove the lower cover of a rod.
7. Using the hammer handle, push out the piston of the block of cylinders up and take it from the block of cylinders.
8. On the lower head of a rod establish a cover of a rod and screw nuts that will allow to keep them in a set and not to mix in places.
9. Similarly remove the piston of the fourth cylinder.
10. Turn a bent shaft on 180 ° for installation of pistons of the second and third cylinder in the lower dead point and similarly remove pistons.


Measurement of diameter of a piston finger

Before check of pistons with rods remove piston rings from pistons and carefully clear pistons.

1. For removal of piston rings from pistons unclench a ring, insert under a ring evenly on a circle two or three old edges of the probe and on them shift a ring from the piston.


Be careful, do not scratch the piston the ends of a ring. Rings very fragile can also burst if to unclench them very strongly. Working edges of piston rings very sharp therefore handle with them very with care not to be cut. You hold each set of rings together with pistons for repeated installation them on the places.

2. Clear all traces of a deposit from the top part of the piston.
3. Remove a deposit from flutes under piston rings in the piston, using an old piston ring.
4. After removal of a raid clear the piston with a rod the corresponding solvent and wipe dry.
5. Carefully examine each piston on existence of cracks around a skirt and openings under a piston finger.
6. Check wear on a piston skirt, an opening in a piston head, and also burned in the top part of the piston.
7. Traces of pointed corrosion on the piston specify that cooling liquid got to the combustion chamber. It is necessary to find the reason of hit of liquid in the combustion chamber and to eliminate it.
8. Measure diameter of the piston.
9. Define a piston gap in the cylinder for what from diameter of the cylinder take away diameter of the piston and divide into two.
10. Check each rod for wear and existence of cracks, and also distortion of a form.
11. Piston fingers are established on the sliding landing and recorded in the piston by two lock rings. On these engines pistons and rods can be divided as follows.
12. Using an edge of the thin screw-driver, remove a lock ring from the piston and a hand squeeze out a piston finger. At repeated installation of a piston finger use only new lock rings.
13. Check a piston finger and the bearing of the top head of a rod for wear.
14. Rods usually do not demand replacement if before it there was no jamming of the engine.
15. Collect the piston and a rod so that the arrow on a head of the piston showed aside, opposite to a tag on a rod.
16. Grease a piston finger and implant it into the piston and the top head of a rod. Check that the piston easily and freely turned on a piston finger.
17. Record a piston finger new lock rings. Check that each lock ring was correctly located in a piston flute. Establish lock rings so that their locks were directed up.
18. The section of a lock ring has to be directed the piston up.

Installation of pistons with rods

On engines both standard inserts of bearings, and nadrazmerny, after regrinding of a bent shaft are applied. The required size of an insert can be determined after measurement of a neck of a bent shaft.

1. Clear a back part of a connecting rod and the place of its installation in rods and covers of rods.
2. Grease pistons and piston rings with pure engine oil and place locks of piston rings according to requirements.
3. Installation of pistons needs to be begun with the first cylinder. Squeeze piston rings on the piston the special device for compression of piston rings.
4. Insert the piston with the mandrel squeezing rings in the top part of the first cylinder. Thus the arrow on a head of the piston has to be directed to a gas distribution mechanism drive chain. Using wooden whetstone or the handle of the hammer, press on the piston and press it into the cylinder.
5. Check combination of the lower head of a rod with a neck of a bent shaft and, if necessary, tighten the piston a rod and establish the lower head of a rod with an insert on a neck of a bent shaft.
6. Establish a cover of the lower head of a rod with an insert. At the same time the ledge on a cover of a rod has to be directed to a flywheel.
7. In several stages tighten fastening bolts the required moment.
8. Similarly install other three piston and a rod.
9. Turn a bent shaft and check that it rotates easily and without jammings.
10. Establish an oil receiver pipe, the oil pallet and a head of the block of cylinders.