After removing the engine from the car, we install it on the stand.

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With a spanner wrench or a head for 17, we unscrew the nut that secures the support of the power unit to the bracket.

Remove the support

Ремонт двигателя ВАЗ-2123

With a 13 key, unscrew the bolt attaching the starter shield to the bracket

We unscrew the four nuts securing the bracket to the cylinder block.

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Remove the bracket from the cylinder block studs. We unscrew the four nuts and remove the left engine support bracket.

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Unscrewing with a 13 key two nuts securing the starter shield to the exhaust manifold, and remove the shield

Remove the ignition module; knock sensor; generator;

- generator bracket; oil filter bracket; oil separator for crankcase ventilation;

- oil pump; coolant pump; flywheel and clutch housing cover;

- a cylinder head complete with a receiver, an inlet pipe and an exhaust manifold;

- timing chain, chain tensioner shoe, crankshaft sprocket; oil pump drive roller.

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With a 10 head, unscrew the six bolts securing the crankshaft rear oil seal holder to the cylinder block

We pry the holder tides with a screwdriver and remove it assembled with an oil seal.

We take out two bolts with square heads from the gland cover. Remove the gasket.

Ремонт двигателя ВАЗ-2123

With a 10 key, unscrew the bolt securing the oil separator drain pipe bracket and remove the bracket

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With a 14 head, we unscrew the two nuts securing the connecting rod cover

We knock with a plastic hammer on the surfaces of the connecting rod cover

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Remove the connecting rod cover

We take out the lower connecting rod bushing

Leaning on the ends of the rods of the connecting rod bolts, we move the lower head of the connecting rod from the journal of the crankshaft

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With the wooden handle of the hammer, we rest against the lower head of the connecting rod and push the piston into the cylinder

We take out the piston with the connecting rod from the cylinder. We also take out the pistons from the other cylinders.

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Opening the lock of the upper compression ring

Remove the upper compression ring.

Also remove the lower compression ring.

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We take out two discs of the oil scraper ring.

Remove the oil scraper ring expander

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To remove the piston from the connecting rod, pry the piston pin retaining ring with a screwdriver

We remove the ring from the groove of the piston boss. In the same way, take out the second retaining ring.

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By sliding the piston pin, remove it from the holes in the piston and in the connecting rod head

Remove the piston from the connecting rod

If the parts are to be reused, then you need to mark them.

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With a 17 head, unscrew the two bolts securing the crankshaft main bearing cover.

Remove the main bearing cover

We take out the main bearing shells from the cover. We also remove the rest of the main bearing caps.

We remove the crankshaft from the block.

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We take out the half rings from the grooves of the rear support of the cylinder block.

We take out the upper liners of the crankshaft main bearings from the cylinder block supports.

Troubleshooting of engine parts

After dismantling the engine, you need to thoroughly wash all the parts with gasoline and remove carbon deposits.

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We measure the diameter of the cylinders with an internal gauge in four belts (at a distance of 8, 15, 50, 90 mm from the upper plane of the block) and in two directions (parallel and perpendicular to the crankshaft axis).

If the wear exceeds 0.15 mm, the block must be bored to the repair size by 0.4 or 0.8 mm.

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To determine the wear of the piston skirt, we measure the diameter with a micrometer in a plane perpendicular to the axis of the piston pin, at a distance of 55 mm from the piston crown.

We measure with a micrometer the diameters of the crankshaft connecting rod journals

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We measure the diameters of the crankshaft main journals

The crankshaft journals are ground to the nearest repair size if their ovality is greater than 0.03 mm, as well as if there are seizures and risks on the journals.

After sanding, remove the plugs from the oil passages and remove any remaining abrasive and deposits.

Installing new plugs

Assembling the engine

We assemble the engine in reverse order. We install new crankshaft bearing shells in size.

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In the first, second, fourth and fifth bearings of the block, we install the upper liners of the main bearings with grooves, and in the third support, liners without a groove on the inner surface.

Apply a thin layer of engine oil to the working surfaces of the main bearing shells and lay the shaft.

We insert persistent half rings lubricated with engine oil into the grooves of the fifth support.

On the front side of the fifth support, we install a steel-aluminum half-ring, and on the back side, a cermet (yellow).

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The working surfaces of the half rings with an anti-friction coating (grooves are made on them) must face the thrust surfaces of the crankshaft.

We install the main bearing caps with liners in accordance with the marks on the outer surface of the caps (counting is done from the side of the camshaft drive).

Liner locks must be on one side.

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We tighten the bolts of the main bearing caps to a torque of 68.31-84.38 Nm (6.97-8.61 kgf.m).

Pistons for cylinders are selected by classes. The cylinder diameter class, indicated by letters, is stamped on the lower plane of the block.

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The diameter classes of the piston skirt and the bore for the piston pin are marked on the piston crown.

The arrow on the bottom of the piston, when installing it in the cylinder, should be directed towards the timing drive.

Using a set of flat dipsticks, we check the clearance in the piston ring lock and lubricate the grooves on the pistons with engine oil. We install rings on the pistons

Before assembling the connecting rod-piston group, it is necessary to pick up the fingers to the pistons and connecting rods.

On new parts, the pin hole class in the connecting rod and piston must correspond to the pin class.

For used parts, for correct mating, it is necessary that the piston pin, lubricated with engine oil, enters the bore of the piston or connecting rod with hand force and does not fall out of them when the finger is vertical.

To check the clearance in the piston ring lock, insert the ring into the cylinder and align the ring with the piston bottom.

If there is a TOP or TOP mark on the ring near the lock, then set the ring with the mark up. The rings should turn freely in the grooves, without jamming.

We arrange the rings as follows:

• the lock of the upper compression ring is oriented at an angle of 45 ° to the axis of the piston ring;

• lock of the lower compression ring - at an angle of 180 ° to the axis of the lock of the upper ring;

• oil scraper ring lock - at an angle of 90 ° to the axis of the upper compression ring lock (the expander joint is located on the side opposite to the lock).

Before installing the ShPG parts, we lubricate the cylinders, pistons with rings and connecting rod bearings with engine oil.

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Install the lower compression ring with the groove down.

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Before installing the piston in the cylinder, we put an adjustable mandrel on the piston and tighten the mandrel, squeeze the rings.

We install the piston with a connecting rod into the cylinder, orienting the piston with an arrow on its bottom towards the timing drive.

Using the hammer handle, push the piston into the cylinder. Having removed the mandrel, we send the piston into the cylinder with the hammer handle.

We look from the other side of the block to fit the lower connecting rod head with an insert on the crankshaft neck.

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When installing the connecting rod caps, the numbers on the connecting rod and the cap must match and be located on one side of the connecting rod.

Tighten the connecting rod nuts with a torque of 43.32–53.51 Nm (4.42–5.4 kgf.m)

Engine break-in after repair

The repaired engine is subjected to bench tests (running in) without load according to the following cycle:

750-800 min. 1 - 2 min.

1000 minutes 1 - 3 minutes

1500 minutes 1 - 4 minutes

2000 mins 1 - 5 mins

Once installed on the bench and starting the engine, check the following:

- whether there is a leakage of coolant or fuel between the mating parts, from the pipe connections and through the gaskets;

- oil pressure and whether there is oil leakage through the gaskets;

- idling speed;

- are there any extraneous knocks.

If extraneous knocks or malfunctions are found, stop the engine, eliminate them, and then continue testing.

If oil leaks through the gasket between the cover and the cylinder head or through the gaskets between the engine oil sump, cylinder block and covers, tighten the mounting bolts to the recommended torque.

If the oil continues to flow, check that the gaskets are correctly installed and replace if necessary.

Since the engine has not yet been run-in after the repair, and the friction of the working surfaces of the new parts has significant resistance to rotation, a certain run-in period is required.

This especially applies to those engines on which pistons, connecting rod and main bearing shells have been replaced, the crankshaft journals have been resurfaced, and the cylinders have been honed.

Therefore, when running in a repaired engine, do not subject it to maximum stress.

Engine break-in should be continued on the vehicle at the recommended speeds for the vehicle break-in period.