If the chain tension cannot be restored with a serviceable tensioner and its shoe, and with unworn drive sprockets, then the chain has stretched excessively and must be replaced
At the same time, it is necessary to replace the worn timing belt and oil pump drive sprockets
You will need: keys "10", "13", "17", a special key for the crankshaft pulley fastening nut, a screwdriver, a mounting blade, a hammer, a punch.
Remove the cylinder head cover (see "Replacing the head cover gasket Niva Chevrolet").
Remove the auxiliary drive pulley
Remove the sprocket with the chain from the camshaft
Remove the chain from the sprocket
The operations are shown on a removed engine
Unscrew the three bolts securing the oil pan to the timing belt cover.
Unscrew the three nuts securing the tension roller bracket and remove the bracket together with the roller.
Unscrew the support roller mounting bolt and remove the roller.
Using a 13 mm wrench, unscrew the plate mounting bolt to the generator bracket.
Using a 10 mm socket, loosen the upper plate mounting bolt
Remove the crankshaft position sensor wire holder bracket shaft
Using a 10 mm head, unscrew the lower plate mounting bolt.
Remove plate.
Using a 10 mm socket, unscrew the five bolts and two nuts securing the timing belt cover to the cylinder block
Use a slotted screwdriver to pry up the cover lugs.
Remove the front timing belt cover.
The cover joint is sealed with a cardboard gasket.
Using a 17 head, unscrew the axle of the chain tensioner shoe.
Remove the tensioner shoe.
Remove the chain from the crankshaft sprockets and the oil pump drive shaft and take out the chain
Remove the sprocket from the toe crankshaft
If the sprocket is tight, press it off using a three-jaw puller
Using a chisel or screwdriver, bend the edge of the locking plate from the head of the bolt securing the sprocket of the oil pump drive shaft.
Using a 17 mm head, unscrew the bolt securing the sprocket.
To prevent the sprocket from spinning, hold it with a screwdriver through the hole in the sprocket, resting on the head of the bolt securing the thrust flange of the shaft.
Remove the bolt with washers
Remove the sprocket of the oil pump drive shaft.
Sprocket on the shaft is fixed with a pin
We install the parts in the reverse order.
In case of a tight fit of the sprocket on the shaft, we press it onto the shaft, tightening the pulley fastening nut.
After unscrewing the nut, press the sprocket using a suitable head.
When installing the chain, ensure that its left branch is tensioned.
The chain must not sag between the crankshaft sprockets, oil pump drive shaft, and camshaft.
After installing the chain and hydraulic tensioner, turn the crankshaft clockwise two turns and check the alignment of the timing marks.
Make sure that the marks on the sprockets coincide with the marks on the engine (see "Installing shafts according to marks on a Niva Chevrolet").
If the marks do not match, repeat the installation of the chain.
If the marks match, engage the gear, tighten the camshaft sprocket bolt and lock it.
Install the removed parts in the reverse order of removal.