Timing Belt: Adjustments

Toothed Drive Belts With HTD Teeth
Beginning With 1983 Models





Note: The shape of teeth on drive belts for camshaft sprockets, oil pump sprocket and crankshaft sprocket has been changed to High Torque Drive (HTD).





CHECKING AND ADJUSTING DRIVE BELT

Checking

1. Remove air guide hoses.





2. Unscrew two hexagon head metal screws and remove air guide upper section from above.





3. Unscrew drive belt guard upper section on both sides and remove.

Crankshaft At TDC:

RH Camshaft:

LH Camshaft:

4. Turn engine in direction of rotation to TDC (cylinder 1). In this position marks on camshaft sprockets should conform with marks on flange bearings.

5. Turn engine two more turns until TDC mark is reached again and check drive belt for damage and wear at same time.





6. Prepare Special Tool 9201 for checking. Pull out lockpin on special tool and slide out gauge pin opposite the lockpin fully. Line up maximum indicator with gauge indicator.

7. Slide special tool on to relaxed section of drive belt (sliding shoes on smooth surface, rollers in tooth gap).





8. Press down tester on case (arrow 1) slowly until gauge button (arrow 2) resting on the air pump bracket engages.

Line up maximum indicator with gauge indicator (in anticlockwise direction).

Read value while keeping the tester free of tension, i.e. horizontal to the drive belt.

Tester must not contact plastic cover.

Note: Sliding shoes must rest on belt with their complete surface. The special tool must not be turned or moved on the belt while checking.

9. Pull out lockpin to have the gauge button disengage again.

Important: This test requires the engine in the position described in point 4. Repeat test one or two times! Adjusting value: 4.5 scale units. Correct belt tightness if necessary.

Adjusting





- The drive belt adjusting screw is located on bottom of engine at front right.

- Loosen nut on adjusting screw and turn adjusting screw until the drive belt tightness is correct. Tighten nut again. Turn engine two more turns and recheck drive belt tightness.

Tightening screw = tightening belt
Loosening screw = loosening belt

Note: Never turn engine anticlockwise, since drive belt could jump out if its tightness is insufficient.