Removal and disassembly
Remove the cylinder head. Cylinder head ZMZ-402 GAZ-2705
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 fixture, 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 ring fragment.
Inspection, verification and repair of parts of the connecting rod and piston group are carried out similarly to operations on the engine mod. 406. Differences are shown below.
The clearance between the oil scraper ring and the groove on the piston must be between 0.135 and 0.335 mm.
The gaps in the locks of the piston rings should be within 0.3–0.7 mm for compression rings and 0.3–1.0 mm for oil scrapers.
Pins and connecting rods are marked with paint: a finger in a hole, a connecting rod on a rod near the upper head.
A Roman numeral is embossed on the piston crown to indicate the piston group.
The pin should not fall out of the connecting rod head when tilted at about 45°.
The difference in mass between pistons assembled with connecting rods, pins, piston rings installed on one engine should be no more than 12 g.
Assembly and installation
The assembly and installation of the connecting rod and piston group are similar to those on the engine mod. 406.
When installing the nuts of the connecting rod bolts, lock them with Unigerm-9 sealant.