The drive of the gas distribution mechanism of the VAZ-2123 engine consists of sprockets, a chain, a shoe, a damper and a hydraulic chain tensioner.
The engine chain is single-link, unlike the engines of previous models.
If, with a good tensioner and its shoe, as well as with unworn drive sprockets, it is not possible to restore the tension of the chain, then the chain has stretched excessively and must be replaced.
When the chain tensioner shoe is worn, the tensioner response range becomes insufficient to restore chain tension.
In this case, replace the shoe.
The damper is located inside the front of the block head on the left and is attached to it from the outside with two bolts.
If the damper is worn or damaged, under certain engine operating conditions, resonant vibrations of the leading branch of the chain can occur, which can lead to chain jumping on the teeth of the camshaft sprocket and serious engine damage.
Of course, if the chain is stretched and you need to change it, then it is advisable to replace all drive parts.
Removing the timing chain and sprockets and oil pump
Remove the cylinder head cover.
Turn the crankshaft until the mark (hole) on the camshaft sprocket matches the mark on the camshaft bearing housing.
Remove the crankshaft pulley.
Disconnect the camshaft sprocket with the chain from the camshaft.
Remove the chain from the sprocket.
Operations for removing the chain are shown on the engine dismantled from the car.
We unscrew the three bolts securing the oil pan to the camshaft drive cover
Remove the bracket assembly with the roller
Remove the support roller mounting bolt and remove it
We unscrew the bolt securing the plate to the generator mounting bracket
Use a 10 key to unscrew the upper bolt of the plate
Remove the crankshaft position sensor wire holder bracket
Use a 10 key to unscrew the lower plate mounting bolt
Remove the plate
With a 10 key, we unscrew five bolts and two nuts securing the timing cover to the block
Pry off the cover with a screwdriver
Remove the cover
Remove the cover gasket
With a head of 17, turn off the axle of the chain tensioner shoe
Removing the chain shoe
Pull out the timing chain
Remove the sprocket from the front of the crankshaft
If the sprocket is tight, then press it with a puller
Knock the sprocket locking key out of the groove with a beard
Remove the key
We bend the lock washer from the head of the oil pump drive sprocket bolt
Holding the sprocket from turning, unscrew the sprocket mounting bolt with a 17 head
Remove the bolt with washers
Remove the star from the roller
After defect detection, we install all parts in reverse order.
If the crankshaft sprocket is tight, then. wrapping the pulley fastening nut, press it onto the crankshaft shaft.
After we press with suitable heads
Before installing the chain, we combine the marks on the sprockets of the crankshaft and camshaft
Timing chain and oil pump failure
Rinse the chain in kerosene and then check the condition of its links.
On rollers and cheeks, chips, cracks and other damage are not allowed.
When the engine is running, the parts of the chain wear out, so the chain is stretched.
It is considered operational as long as the tensioner provides its tension, i.e. if the chain elongation does not exceed 4 mm.
We determine the length of the chain using tool 67.7824.9521
Adaptation 67.7824.9521 has two stepped measuring rollers 1, on which the chain is installed when measuring its length.
One of the rollers is fixed in the fixture body, and the second can move under the action of the measuring force P.
With the help of counterweight 3 (see figure 1), the chain is stretched with a force of 294 N (30 kgf) or 147 N (15 kgf).
Adjusting nut 2 ensures that the axis of the counterweight is parallel to the base of the fixture.
The length of the chain is determined by the center distance L of the measuring rollers 1 (see figure 2).
The new chain has a length L of 495.4-495.8 mm. If the chain is 499.8 mm long due to wear, it should be replaced.
Chain length measurement scheme
Measure the chain length in the following sequence:
- - stretch the chain with a force of 294 N (30 kgf) by placing the counterweight 3 (see Figure 1) in the extreme right position, then reduce the force to 147 N (15 kgf) by moving the counterweight to the extreme left position;
- - repeat both operations again;
- - having measured the internal distance between the measuring rollers 1 with a caliper and adding the diameter of the roller d to it, you will get the chain length L. (the distance between the axes of the measuring rollers).
Lubricate the chain with engine oil before installing it on the engine.
Removal and troubleshooting of the hydraulic chain tensioner in the article - "Removal and troubleshooting of the hydraulic tensioner chains VAZ-2123»