Removal and installation of the crankshaft of the ZMZ-406 engine

Remove the oil sump and crankcase gasket

Remove the oil pump.

Remove the camshaft drive chains.

Remove six bolts 1 for fastening the flywheel, remove the washer 2 for the flywheel bolts.

Remove flywheel 3.

Remove six bolts 1 and remove oil seal holder 2 with crankshaft rear oil seal 3 pressed into it.

Remove the stuffing box gasket.

If you do not need to remove the pistons from the cylinders, you can not remove the block head, just unscrew the nuts of 3 connecting rod bolts, remove the covers of 5 connecting rods and carefully slide the pistons into the cylinders.

Remove bolts 1 and remove main bearing caps 6.

Since the lids are tight, knock them down with light blows from a hammer. Remove the upper half washers 4 thrust bearings.

Remove crankshaft 2 with gear and bushing 7 as an assembly.

Remove the main bearing shells and the lower half washers of the thrust bearing from the beds of the main bearings and caps.

Checking and repairing the crankshaft

Rinse all parts with gasoline and dry.

Inspect the crankshaft. If it has cracks, it must be replaced.

Remove the plugs, wash with gasoline and blow out the oil channels of the crankshaft with compressed air. Wrap the plugs and tighten them to a torque of 38–42 N m (3.8–4.2 kgf m).

If the main and connecting rod journals have minor burrs, marks, scratches, or the ovality of the journals exceeds 0.01 mm, they should be ground to the repair size.

After grinding, polish the necks. Grind the shaft journals to one of the repair sizes indicated in the table.

Burn the sharp edges of the chamfers of the oil channels with an abrasive cone.

After grinding, rinse the crankshaft and blow out the oil passages with compressed air.

After grinding the crankshaft journals, it is necessary to install the main and connecting rod bearing shells of the appropriate repair size.

Inspect the main bearing shells. If they have scratches, scuffs, scratches, delaminations, inclusions of solid particles, etc., replace the liners.

Inspect the flywheel. If the teeth of the flywheel crown are damaged, there are scuffs, scratches, etc. on the surface adjacent to the clutch disc, replace the flywheel.

If the flywheel is cracked, it should also be replaced.

The toe bearing of the input shaft of the closed type is pressed into the flywheel.

Inspect the bearing, if defects are found (large play, seizing, damage to protective rings, etc.), press it out of the flywheel.

Press the new bearing flush with the bottom edge of the chamfer of the hole in the flywheel

Inspect the front and rear crankshaft oil seals in the chain cover (pictured) and oil seal holder.

They should not be damaged (tears, tears or heavy wear of the working edge, etc.).

Replace damaged oil seals. To do this, remove the old oil seal with a screwdriver and press in a new one.

If the vehicle has a high mileage, it is recommended to replace both oil seals when disassembling the engine.

Measure the diameters of the main and connecting rod journals of the crankshaft.

If the diameters of the crankpins are less than 55.92 mm, the main ones are 61.92 mm, you need to grind the necks to the repair size.

All main or connecting rod journals must be ground, even if only one journal is less than the specified maximum allowable size.

Crankshaft disassembly

Disassembly of the crankshaft is required before grinding its necks, and to replace the timing gear sprocket.

Compress the coupling with a puller.

If there is no puller, remove it with blows through a brass mandrel.

Having prying with a screwdriver, remove the rubber ring, having previously knocked out the key from the shaft slot.

We press the sprocket with a brass mandrel and, prying with a screwdriver, remove the sprocket key.

After grinding the crankshaft journals with a 14-head bolt and lock nuts, we unscrew the plugs.

We carefully clean the channels for the passage of oil in the crankshaft from deposits and abrasive residues.

We wash the channels of the crankshaft with kerosene, gasoline or diesel fuel and blow it with compressed air.

We wrap the plugs of the oil channels in place

With a beard we kern the edges of the plugs

Assemble the shaft in reverse order. We start pressing the sprocket and clutch by installing the corresponding keys in the groove of the crankshaft.

Installing the crankshaft

Installation is carried out in the reverse order of removal, taking into account the following:

In the main bearing caps, liners without grooves are installed, and in the bed - with grooves.

The upper half-washers of the thrust bearing are installed in the grooves of the bed of the 3rd main bearing with an antifriction layer to the crankshaft cheek, the lower ones - together with the cover, while the antennae of the half-washers should enter the grooves of the cover.

Before installing, lubricate the main and brass crankshaft journals, the main bearing shells and the thrust bearing half washers with engine oil.

Tighten the main bearing cap bolts to 100–110 Nm (10–11 kgf m).

Tighten the flywheel mounting bolts to a torque of 72–80 N m (7.2–8.0 kgf m). Turn the crankshaft before connecting the connecting rods. It should rotate easily, without jamming.

Nominal and maximum permissible dimensions and fit of mating parts of the crankshaft