Installed Lenght and Colour Code of Valve Springs

Type 928 S

Intake valve 38.5+0.5 mm Exhaust valve 37.5+0.5 mm

Check installed length with special tool 9138 and correct by installing or removing shims if necessary.

from 3.81 colour code -1 white line -

Intake valve 41.5+0.5 mm Exhaust valve 40.5+0.5 mm

From engine number codes 8210516 M 28/11 and 8215503 M 28/12 automatic, sets of valve springs are used with progressive outer springs on both ends (formerly only at one end). The valve spring seat has been enlarged in the cylinder head.

to 2.81

to 2.81

from 3.81

The new cylinder heads can be installed in old engines in pairs or only on one side of the engine together with the previous version. At the same time, the valve springs progressive on both ends with accessories must be used on the new cylinder heads.

from 3.82 colour code - 2 or 3 white lines -

Intake valve 41.0+0.5 mm Exhaust valve 40.0+0.5 mm

New valve springs marked with 2 or 3 white lines are to be installed only with the new valve seats and guide plates.

Valve seat

Guide plate

new 25.75 mm 0 previous 25.60 mm 0 "

Check installed length with special tool 9138/1 and correct by installing or removing shims if necessary.

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Important Engine Tuning Values - Type 928

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Country Specifications Model Year Engine Type

Europe, R.o.W. 81/82 M 28.09/10

USA 81/82 M 28.15/16

Japan 81/82 M 28.17/18

Ignition timing * at engine rpm Vacuum hose detached

28° before TDC 3000

yes

Ignition timing control at engine rpm Vacuum hose detached

Idle speed 700±50

9° to 13° before TDC

Idle speed 750±50

8° to 10° before TDC

Idle speed 750±50

8° to 10° before TDC

Idle speed in rpm

700±50

750±50

750±50

CO level in % (engine oil temperature about 80° C)

1.5±0.5**

0.6±0.2***

0.6±0.2***

Control pressure „cold" with about 20 ° C ambient temperature and engine stopped (without vacuum)

1.3±0.2 bar

Control pressure „cold" with about 20 ° C ambient temperature and engine running (with vacuum)

1.8±0.2 bar

* For 80 to 90° C oil temperature

** Auxiliary air injection disconnected and line to engine plugged *** Measured ahead of catalytic converter; oxygen sensor disconnected Note: Ignition timing Model 81/82 for Sweden and Australia 23° before TDC (as USA/Japan)

* For 80 to 90° C oil temperature

** Auxiliary air injection disconnected and line to engine plugged *** Measured ahead of catalytic converter; oxygen sensor disconnected Note: Ignition timing Model 81/82 for Sweden and Australia 23° before TDC (as USA/Japan)

Country Specifications Model Year Engine Type

M 28.09/10

USA 81/82 M 28.15/16

Japan 81/82 M 28.17/18

Control pressure „warm" without vacuum, with engine stopped and fuel pump running with vacuum, at idle speed

3.0±0.2 bar 3.6±0.2 bar

System pressure Test value System pressure Adjusting value

5.3 - 5.5 bar

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Fuel pressure (engine stopped) Fuel pump running (relays bridged)

Control value at idle speed

2.5±0.2 bar approx. 2.0 bar

2.5±0.2 bar approx. 2.0 bar

Leak test (fuel system) Engine warm

Min. pressure after 10 minutes Min. pressure after 20 minutes Min. pressure after 30 minutes

2.7 bar 2.6 bar 2.5 bar

_

Electric fuel pump delivery rate

at least 1120 cc/30 s

at least 1150 cc/30 s

at least 1150 cc/30 s

Important Engine Tuning Values - Type 928 S

Country Specifications

Europe, R.o.W.

Australia/ Sweden

USA/Japan

Europe, R.o.W.

Model Year Enqine Type

80/81/82/83 M 28.11/12

80/81/82/83 M 479-M 62

83/84 M 28.19/20

M 28.21/22

Ignition timing * at engine rpm Vacuum hose detached

26° before TDC 3000

yes

20° before TDC Electronic 3000 Ignition System yes

Ignition timing control at engine rpm Vacuum hose detached

Idle speed

700+50

TDC

Idle speed 700±50 2 ° after TDC to 2° before TDC

Idle speed 650±50 4° - 8° before TDC

Idle speed 700+50 10°± 3° before TDC

Idle speed in rpm

700+50

700±50

650 ±50

700+50

CO level in % (engine oil temperature about 80° C)

1.5...2.5**

1... 2**

0.6±0.2 ***

0.5.. .1.5** (Intake airtempera-ture: +15 to +35°C/ + 59 to +95° F)

Control pressure „cold" with about 1.1 ±0.2 bar 20° C ambient temperature and engine stopped (without vacuum)

1.1 ±0.2 bar

Control pressure „cold" with about 1.6±0.2 bar 20° C ambient temperature and enaine running (with vacuum)

1.6±0.2 bar

* For 80 to 90° C oil temperature

** Auxiliary air injection disconnected and line to engine plugged *** Measured ahead of catalytic converter; oxygen sensor disconnected Note: Ignition timing Mod. 80/81/82/83 Australia 23° before TDC,

CO level Mod. 84 for Australia, Switzerland and Sweden 0.5.. .1.0 %

Country Specifications

Model Year Engine Type

80/81/82/83 M 28.11/12

Australia/ Sweden 80/81/82/83 M 479-M 62

US A/ Japan

83/84 M 28.19/20

M 28.21/22

Control pressure „warm"

without vacuum, with engine stopped and fuel pump running with vacuum, at idle speed

3.0±0.2 bar 3.6±0.2 bar

3.0±0.2 bar 3.6±0.2 bar

System pressure Test value 5.2... 5.8 bar System pressure Adjusting value 5.3... 5.5 bar

5.2...5.8 bar 5.3 ... 5.5 bar

Fuel pressure (engine stopped) Fuel pump running (relays bridged)

Control value at idle speed

2.5±0.2 bar approx. 2.0 bar

2.5±0.2 bar approx. 2.0 bar

Leak test (fuel system) Engine warm

Min. pressure after 10 minutes Min. pressure after 20 minutes Min. pressure after 30 minutes

2.7 bar 2.6 bar 2.5 bar

2.7 bar 2.6 bar 2.5 bar

1 bar

Electric fuel pump delivery rate

at least 1120 cc/30 s

at least 1120 cc/30 s

at least 1150 cc/30 s

at least 1350 cc/30 s

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