Repair of the connecting rod and piston group ZMZ-402

Remove the cylinder head (see How to remove and install the cylinder head ZMZ-402)

Remove the oil pump

Remove the nuts 1 of the connecting rod bolts and remove the connecting rod cap 2.

Since the lid sits tightly, knock it down with gentle hammer blows.

Remove the connecting rod bearing shell from the cover.

Push the piston into the cylinder so that it comes out of the cylinder, and then remove it along with the connecting rod.

Remove the connecting rod bearing shell from the lower end of the connecting rod.

Remove the piston with the connecting rod from the cylinder carefully so as not to damage the cylinder mirror.

Check the marks on the connecting rod and connecting rod cap.

If the marks are not visible, mark the connecting rod and cap with the cylinder number.

In the same way, remove the remaining pistons with connecting rods.

Remove the piston rings using a puller.

Remove the circlips from both sides of the piston.

Press out the piston pins with a special tool.

If there is no tool, you can knock out the piston pins with light hammer blows through the mandrel 1 - this must be done by weight so as not to damage the piston.

Remove connecting rod 2 from piston 3.

In the same way, remove the remaining pistons from the connecting rods.

After disassembly, wash all parts in gasoline.

Clean the pistons from carbon deposits.

Clean the piston ring grooves with an old piston ring or a broken ring.

Dimensional groups of pistons, connecting rods and pins

Nominal and maximum allowable dimensions, fit of mating parts of the connecting rod and piston group of the ZMZ-402 engine