Working with a toothed belt
The adjustment of the camshaft and injection pump is carried out very accurately on a diesel engine.
Any change in the belt tension or its replacement entails adjustment work. Therefore, they are limited to maintenance work carried out with the help of simple devices and periodic monitoring of the belt tension. If the belt is tightened or completely removed (to replace it or remove the cylinder head), then the timing of the valve timing and the start of injection of the injection pump must be checked or adjusted. Both of these jobs require special knowledge and, above all, special tools. You can buy the tools necessary for adjusting the valve timing in special stores. Measuring hours required for injection timing adjustment (hour indicator) with a special adapter is also not easy to install. Here you need to resort to the help of a service station «Volkswagen» or «Bosch».
Our offer for brave drivers: install the toothed belt and adjust the gas distribution headlights yourself. Then take the vehicle to a workshop and adjust the injection timing there.
Removing the toothed belt cover
Unscrew the bolt of the spacer clamp on the front side of the cover.
Release the two spring clips and remove the top of the cover.
The lower part of the cover can be removed only after dismantling the crankshaft pulley and unscrewing the two fixing bolts.
Checking the condition of the toothed belt
Remove the top part of the toothed belt cover.
The toothed belt must not be oily or cracked.
The edges of the teeth must be intact and show no signs of wear.
To view the belt along its entire length, you need to turn the engine.
Damaged belt must be replaced!
Toothed belt tension control
This check should be carried out in conjunction with checking the condition of the belt. The special tool VW210 is used. This device checks the tension of a belt stretched to a certain length. The measurement is carried out between the gears of the camshaft drives and the injection pump.
Remove toothed belt cover.
Press the belt strongly by hand at the measurement point, while the full deflection is at the measurement point.
Attach the device and note its readings.
Rotate the crankshaft. Turn only on the crankshaft pulley, not on the camshaft pulley!
Repeat measurement.
Get the average of two measurements.
If the measured value reaches 12-13, then everything is in order. Otherwise tighten the belt.
Belt tightening
In workshops, a MATRA V 159 nut driver is used to turn the adjusting eccentric. Here we will describe how the adjustment can be carried out without a nut driver.
Remove toothed belt cover, measure belt tension.
Slightly loosen the clamping nut on the tension roller. The roller should not yet move back and forth on the eccentric under the action of the hand.
Insert a screwdriver into one of the holes on the camshaft sprocket.
Using a screwdriver, turn the camshaft pulley slightly to the left so that the belt is released on the tensioner side.
Now, using a small hammer, gently hit the left side of the tension roller, while it slides a little to the right along the eccentric and thus the belt is tensioned. In this case, of course, the camshaft gear must be held further.
Tighten the pressure nut on the tension roller.
Check belt tension again.
Be sure to check the start of the injection pump.
The location of the toothed belt with the cover removed
1 - tension roller
2 - camshaft gear
3 - toothed belt
4 - gear wheel injection pump
Toothed belt replacement
Two sets of calibration probes are used, a VW 2065 or 2065 A adjusting ruler and a 2064 marking rod.
Removing
Remove the belt cover and valve cover.
Install the first cylinder in the MTV.
Insert a straightedge into the camshaft cross slot at the left end of the camshaft (in the direction of travel).
Between the cylinder head and the adjusting ruler is now inserted at both ends of the ruler, one probe of the same thickness (average), see fig. Thus, the gap between the ruler and the cylinder head is eliminated - the camshaft can no longer turn back and forth.
Stop injection pump. To do this, the marking rod 2064 (2) insert into the small hole on the gear wheel of the injection pump and the hole in the injection pump console located opposite.
Loosen the clamping nut of the toothed belt tensioner. Turn the tension roller on the eccentric to the left; this will loosen the belt.
Remove V-belt.
Remove the pulley and part of the cover.
Remove toothed belt.
Installation
Before installing a new toothed belt, loosen the camshaft gear bolt by ½ turn.
Loosen the camshaft wheel with light hammer blows through the rod from the tapered end of the camshaft (there is a hole on the back cover of the toothed belt for this).
Now the wheel can rotate relative to the camshaft.
Check again. whether the crankshaft is at TDC and whether the camshaft and injection pump are properly locked.
Put on the toothed belt and tension it. Do not turn the crankshaft while doing this.
Tighten the gear wheel fixing bolt to 45 Nm.
Tighten the toothed belt again. The crankshaft cannot turn now.
Be sure to check the moment of injection of the injection pump.
Wear a cover.
Put on the V-belt.
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