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 gentle hammer blows.
Remove the upper half washers 4 of the thrust bearing.
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.
Inspection and repair
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.
Put on the plugs and tighten them to a torque of 38–42 Nm (3.8–4.2 kgf m).
If there are minor burrs, marks, scratches or ovality of the journals on the main and connecting rod journals exceeding 0.01 mm, they should be ground to the repair size.
After grinding, polish the necks.
It is necessary to 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 marks, 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 has cracks, it must 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 connecting rod journals 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 journals 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.
Installation
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 web, 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 72–80 Nm (7.2–8.0 kgf m).
Crank the crankshaft before connecting the connecting rods. It should rotate easily, without jamming.
