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Toothed Belt, Remove and Install
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General Instructions:
Install toothed belt on cold engine
(room temperature) only. Replacement of toothed belt must be
documented on dedicated sticker. The new toothed belt has guide
marks which must be observed on installation.
| 1. |
Single dash for camshaft sprockets. |
| 2. |
Arrow marks indicating the running direction. |
| 3. |
Double dash for toothed belt drive gear. |
If these guide marks are no longer visible, the toothed belt
must be replaced.
Caution
Do not remove toothed belt under any circumstances unless
camshaft sprockets and toothed belt drive gear have been adjusted
and locked in "TDC" position using KM-800. Improper assembly of
toothed belt can lead to engine damage. Misalignment of one tooth
on a toothed belt can cause damage to valves and pistons. Always
turn crankshaft uniformly in engine rotational direction.
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Required special service tools:
| 1. |
KM-800-1 (red) |
| 2. |
KM-800-20 |
| 3. |
KM-800-2 (green) |
| 4. |
KM-800-10 |
| 5. |
KM-800-30 |
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| 1. |
Camshaft sprocket "1" for cylinder 1-3-5
(exhaust) |
| 2. |
Camshaft sprocket "2" for cylinder 1-3-5
(intake) |
| 3. |
Toothed belt guide roller for adjustment of
camshaft sprockets for cylinders 1-3-5 |
| 4. |
Camshaft sprocket "3" for cylinder 2-4-6
(intake) |
| 5. |
Camshaft sprocket "4" for cylinder 2-4-6
(exhaust) |
| 6. |
Toothed belt guide roller for adjustment of
camshaft sprockets for cylinders 2-4-6 |
| 7. |
Toothed belt drive gear |
| 8. |
Toothed belt tension roller |
- Tension toothed belt
- Release toothed belt
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 Remove
Remove front toothed belt cover – see operation "Front
Toothed Belt Cover, Remove and Install".
Remove torsional vibration damper – counterhold at
fastening bolt of toothed belt drive gear.
 Adjust
At the fastening bolt of the toothed belt drive gear, turn
crankshaft in engine rotation direction to just before TDC point
mark (3) – turn crankshaft slowly and smoothly.
Notches on camshaft sprockets (1) are just in front of marks (2)
on rear toothed belt cover.
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Install
Bolt KM-800-10 (1) to toothed belt drive gear with knurled bolt
(3). Turn crankshaft further in engine rotational direction until
lever (5) contacts coolant pump flange.
Press movable lever (2) of KM-800-10 onto flattening of coolant
pump flange and tighten knurled bolt (4).
Note: The crankshaft
is now locked in the TDC position.
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Inspect
Marks (2) on camshaft sprockets align with notches (1) on rear
toothed belt cover.
Install
Fix camshaft sprockets in position.
Camshaft sprockets "3" and "4" with KM-800-2 (3) (green handle).
Camshaft sprockets "1" and "2" with KM-800-1 (4) (red handle).
Note: Insert
KM-800-1/-2 into camshaft sprockets with the designation "TOP" on
top.
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Inspect
I: If KM-800-2 (green handle) does not fit in the splines of the
camshaft sprockets, loosen toothed belt guide roller (1) and turn
the eccentric with MKM-6038 until KM-800-2 can be inserted.
II: If KM-800-1 (red handle) does not fit in the splines of the
camshaft sprockets, loosen toothed belt guide roller (1) and turn
the eccentric with MKM-6038 until KM-800-1 can be inserted.
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Remove
Loosen toothed belt tension roller.
Release toothed belt via toothed belt tension roller (1)
over-tension again at eccentric (inner hex – A/F 5) in
direction of arrow (clockwise) until eccentric reaches right
stop.
Tighten toothed belt tension roller (1).
Loosen toothed belt guide rollers (2) and (3).
Remove toothed belt.
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Caution
Before installation, the toothed belt must be checked for
kinking and fissures and must be replaced if necessary. If any of
the guide marks on the toothed belt are no longer visible, then the
toothed belt must be replaced as well. The same applies to toothed
belts, toothed belt guide rollers and toothed belt tension rollers
which are contaminated with oil. Install the toothed belt on a cold
engine – room temperature.
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Install
Install new toothed belt.
Note running direction of toothed belt – arrow marks on
toothed belt point in engine rotational direction (clockwise).
Double dash (1) on toothed belt must align with groove (2) on
oil pump and notch (3) on toothed belt drive gear.
To prevent toothed belt jumping during installation, wedge
KM-800-30 (4) between oil pump and toothed belt drive gear.
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Caution
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There are various sequences for installing the toothed belt due
to the various base plate assemblies (4) (toothed belt tension
roller, toothed belt guide roller and base plate). The toothed belt
tension roller and toothed belt guide roller can only be replaced
as an assembly together with the base plate. It is essential that
the appropriate toothed belt is installed for the base plate
assembly.
Option 1:
Toothed belt tension roller (5) without front flanged wheel and
with code letter "D" (3) on the base plate (4) – 60.000 km /
4 years.
Install
Position toothed belt via toothed belt guide roller (2) and
camshaft sprocket "4" and "3" – make sure that torsion side
(I) is tensioned – the excursion of the tension side of the
toothed belt between the toothed belt guide roller and camshaft
sprocket "4" should not exceed 1 cm.
The positioning marks (one dash each) on the toothed belt must
align with the notches of the camshaft sprockets and rear toothed
belt cover. Install toothed belt above toothed belt tension roller
(1) camshaft sprocket "2" and "1" as well as toothed belt tension
roller (5).
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Option 2:
Toothed belt tension roller (5) without front flanged wheel and
with code letter "E" – "EA" (3) etc. or code number "01" on
the base plate (4) – 120.000 km / 8 years.
Install
Position toothed belt on toothed belt tension roller (5) and
camshaft sprocket "1" and "2", toothed belt guide roller (1),
camshaft sprockets "3" and "4" and toothed belt guide roller (2)
– ensure that tension side (I) is taut – the deflection
of the toothed belt tensioned side between the toothed belt guide
roller and camshaft sprocket "4" should not exceed 1 cm.
The positioning marks (one dash each) on the toothed belt must
align with the notches of the camshaft sprockets and rear toothed
belt cover.
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Caution
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Adjustment of the toothed belt tension always starts at the
toothed belt guide roller (2).
Adjust
Turn eccentric of toothed belt guide roller (2) with MKM-6038 in
direction of arrow (anti-clockwise) until the pointer of the
eccentric (arrow) is at approx. "2 o'clock". Tighten toothed belt
guide roller (2).
Adjust toothed belt guide roller (1) – turn eccentric of
toothed belt guide roller (1) with MKM-6038 in direction of arrow
(anti-clockwise) until the pointer of the eccentric (arrow) is at
approx. "11 o'clock". Moderately tighten toothed belt guide
roller.
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Loosen toothed belt tension roller.
Over-tension toothed belt via toothed belt tension roller
over-tension again at eccentric (inner hex – A/F 5) in
direction of arrow (anti-clockwise) until it just reaches stop and
allow to slide back until a measurement of approx. 1 mm is attained
(see Illustration J 0344).
Tighten toothed belt tension roller.
Remove
Remove all retaining and adjusting tools.
Adjust
At the fastening bolt of the toothed belt drive gear, turn
crankshaft two turns (720°) in engine rotation direction until
just before TDC point mark – turn crankshaft slowly and
smoothly.
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Install
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Bolt KM-800-10 (1) to toothed belt drive gear with knurled bolt
(3). Turn crankshaft further in engine rotational direction until
lever (5) contacts coolant pump flange.
Press movable lever (2) of KM-800-10 onto flattening of coolant
pump flange and tighten knurled bolt (4).
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Adjust
Place Test Gauge KM-800-20 on camshaft sprockets "3" and "4"
(cylinder 2-4-6).
Marks (1) are located in front of the with marks on Test Gauge
KM-800-20 (i.e. in front of TDC mark).
Turn eccentric of toothed belt guide roller with MKM-6038 (2) in
direction of arrow (anti-clockwise) until marks (1) of camshaft
sprockets align with those of Test Gauge KM-800-20 – cone end
of eccentric is now positioned at approx. "12 o'clock".
Tighten toothed belt guide roller and remove Test Gauge
KM-800-20.
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Caution
Adjustment of camshaft sprockets 1 and 2 (cylinder 1-3-5) may
only be commenced once camshaft sprockets 3 and 4 (cylinders 2-4-6)
have been exactly adjusted.
Adjust
Place Test Gauge KM-800-20 on camshaft sprockets "1" and "2"
(cylinder 1-3-5).
Marks (1) are located in front of the with marks on Test Gauge
KM-800-20 (i.e. in front of TDC mark).
Turn eccentric of toothed belt guide roller in direction of
arrow (anti-clockwise) with MKM-6038 (2) until the marks (1) on the
camshaft sprockets align with those on Test Gauge KM-800-20 –
pointer of eccentric is now at approx. "9 o'clock" position.
Tighten toothed belt guide roller and remove Test Gauge
KM-800-20.
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Release toothed belt tension roller and over-tension again at
eccentric (inner hex – A/F 5) until it just reaches the stop
(anti-clockwise) and allow to slide back in direction of arrow
(clockwise) until mark (1) is located approx. 3 to 4 mm above mark
(2).
Tighten toothed belt tension roller – tightening torque 20
Nm / 15 lbf. ft.
Tighten toothed belt tension roller – tightening torque 40
Nm / 30 lbf. ft.
Remove
Remove all retaining and adjusting tools.
Adjust
At the fastening bolt of the toothed belt drive gear, turn
crankshaft two rotations (720°) in engine rotational direction
to TDC mark. Turn crankshaft slowly and smoothly.
Fit KM-800-10 again. Using Test Gauge KM-800-20, check
adjustment of all camshaft sprockets, if necessary repeat adjusting
procedure, starting at camshaft sprockets for cylinders 2-4-6
– see operation "Timing, Adjust".
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Note: The dash marks
on the toothed belt do not align with the camshaft sprocket notch
marks after one or more engine revolutions – they are only
used for installation!
Remove
Remove KM-800-10 and KM-800-20.
Install
Install torsional vibration damper – counterhold on the
fastening bolt for the toothed belt drive gear – tightening
torque 20 Nm / 15 lbf. ft.
Install front toothed belt cover – see operation "Front
Toothed Belt Cover, Remove and Install".
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