Removal and troubleshooting of the VAZ-2123 chain tensioner

Removal and inspection of the hydraulic timing chain tensioner of the VAZ-2123 engine

The timing chain tensioner is located on the right-hand side of the engine above the cooling system pump.

Oil is supplied to the hydraulic tensioner through a 6 mm diameter seamless steel pipe with end fittings.

The pipe is connected to a threaded hole into which the union of the emergency oil pressure sensor is screwed. A correctly selected bending stiffness of the pipe made it possible to damp its vibrations; in addition, metal holders with rubber inserts are used to suppress vibration.

The pipe end fitting is secured to the tensioner body by a banjo bolt, which is used for securing the front brake hose of rear-wheel-drive cars and the VAZ all-wheel-drive families.

The tensioner plunger presses on a guide shoe, made, like the chain damper, of wear-resistant plastic. The tensioner shoe pivots on an axis located in the lower part of the cylinder block, to the right of the crankshaft sprocket.

Removal of the chain tensioner

Unscrewing the oil supply pipe bolt
Fig. 1. Unscrewing the bolt securing the oil supply pipe to the tensioner
  1. Using a 13 mm socket, we unscrew the bolt securing the oil supply pipe to the tensioner.
Removing the banjo bolt
Fig. 2. Removing the banjo bolt with copper washer
  1. We remove the copper washer and withdraw the banjo bolt with its copper washer.
Unscrewing the tensioner mounting nuts
Fig. 3. Unscrewing the nuts securing the tensioner to the cylinder head
  1. Using a 10 mm socket, we evenly unscrew the two nuts securing the tensioner to the cylinder head.
Extracting the tensioner
Fig. 4. Extracting the tensioner
  1. We extract the tensioner.
Parts securing the oil supply pipe to the tensioner
Fig. 5. Parts securing the oil supply pipe to the tensioner
Gasket under the tensioner
Fig. 6. Gasket under the tensioner

A gasket is fitted under the tensioner.

After inspection and fault diagnosis, we refit the tensioner in the reverse order.

Operation and inspection of the hydraulic chain tensioner

Hydraulic chain tensioner
Fig. 7. Hydraulic chain tensioner: 1 - tensioner body; 2 - valve assembly; 3 - non-return valve ball; 4 - retaining pin; 5 - tensioner plunger; 6 - volume restrictor; 7 - plunger spring; В - working cavity; С - locating slot; Д - orifice; Е - reserve cavity

Oil from the lubrication system flows through pipe 3 (see Fig. 7) into cavity (Е) of the tensioner, then through orifice (Д) and valve assembly 2 into the working cavity (В) and presses on plunger 5. In body 1 of the tensioner there is a 1 mm diameter hole for bleeding air from cavity (Е).

The diametral clearance between body 1 and plunger 5 must be 0.018—0.024 mm and is measured as the difference between the maximum measured diameter of plunger 5 and the minimum measured diameter of body 1. During repair, the tensioner body and plunger form a pair in which replacement of one part by another after clearance selection is not permitted.

Plunger 5 must move in body 1 without jamming through a stroke equal to 16 mm. When fitted to the engine, the tensioner must be free of oil and pin 4 must not protrude from the body.