Modifications to the precombustion chambers - ra01006010416x(0416)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Engines 601, 602 (except 602.98), 603

Precombustion chamber combustion bore pattern modified

As of 06/86 the combustion bore pattern of the precombustion chambers was modified to improve combustion on engines 601.91, 602.91 and 603.91.

Modified precombustion chambers are marked with the code number 601/17.

Fig 1: Identifying Modified Precombustion Chambers Are Marked With Code Number 601/17

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Collar height on upper section of precombustion chamber increased

As of 09/87 the collar height (d) on the upper section of the precombustion chamber on engines 601.91, 602.91, 603.91 and 603.96 was increased from 5 mm to 6 mm.

Engines 601.91 and 602.96 with angular injection are not affected by this modification.

Fig 2: Identifying Collar Height On Upper Section Of Precombustion Chamber

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Precombustion chambers with angular injection

The shape and design of the precombustion chambers has been changed in the course of improving the emissions (exhaust gas recirculation).

Shape of prechambers

The installation bore was inclined 5° to the longitudinal axis of the precombustion chamber. This results in the injection nozzles injecting the fuel into the precombustion chamber at a slight angle rather than vertically.

Fig 3: Identifying Shape Of Prechambers

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

A Precombustion chamber with vertical injection

B Precombustion chamber with angular injection

Peculiarities of precombustion chambers

The insert pin is produced using a heat-resistant material (Incoloy) due to the higher thermal load.

A cone (x) on the insert pin and a recess (y) at the bottom of the precombustion chamber serve to give the air/fuel mixture a better swirl.

Moreover the volume of the precombustion chambers on engines 603.962 and 603.90 was increased from 10.34 cm³ to 11.37 cm³ .

Fig 4: Identifying Peculiarities Of Precombustion Chambers

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Installation of nozzle holder

For angular injection the nozzle holder (114) is inserted into the upper section of the precombustion chamber turned 180° in relation to the previous position. A threaded ring (112) with inner splines serves for installing the nozzle holder.

A sealing sleeve (109) is located in the gap between the threaded ring and nozzle holder to protect against contamination (discontinued as of 08/93)

Fig 5: Identifying Nozzle Holder Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Threaded ring for holding nozzle holder

The threaded ring used for angular injection is equipped with inner splines.

The groove for a pin wrench present on the threaded ring for vertical injection is no longer present.

A Threaded ring, vertical injection (threaded on inside)

B Threaded ring, angular injection (inner splines)

Fig 6: Identifying Threaded Ring For Holding Nozzle Holder

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

The splined wrench 603 589 00 09 00 is required for removal and installation of the threaded ring with inner splines.

Precombustion chambers turned 180°

Due to other modifications to the nozzle holder combination in relation to the precombustion chamber longitudinal axis the former is inclined at an angle of 5° and installed in the upper section of the precombustion chamber turned 180°.

Fig 7: Identifying Splined Wrench (603 589 00 09 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Differences in precombustion chambers

Fig 8: Identifying Differences In Precombustion Chambers (1 Of 2)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 9: Identifying Differences In Precombustion Chambers (2 Of 2)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

A Code 601/07 or 17/09 or 23

B Code 601/14/15 5° inclined (engine 601.91 as of 10/87 )

C Code 601/25/26/30/36 5° inclined, turned 180° (all engines as of 06/88)

Fig 10: Identifying Precombustion Chambers

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

SURVEY, PRECOMBUSTION CHAMBERS

Engine

601.91 ⁽¹⁾ 602.91 ⁽¹⁾ 603.91 ⁽¹⁾

603.96 up to 9/88

601.91

⁽²⁾ as of 10/86 up to 8/88

602.961 up to 09/88

601.91 ⁽²⁾ 602.91 ⁽²⁾ 603.91 ⁽²⁾ as of 09/88

602.961 as of 09/88 602.962 Standard 602.96

as of 1989 603.96

as of 09/88

603.962 ⁽²⁾ 603.970 ⁽²⁾

as of 09/88 603.971 ⁽³⁾ as of 09/92 as of 04/94 602.96/603.96 ⁽⁶⁾ 603.97 ⁽⁶⁾

Code

601/07 or 17

601/09 or 23

601/14

601/15

601/25 or 29 ⁽⁵⁾

601/26 601/36 ⁽⁴⁾

601/30 601/36 ⁽³⁾

Version

Combustion neck OD (mm)

⁽¹⁾	¹⁾ Without exhaust gas recirculation

⁽²⁾	²⁾ With exhaust gas recirculation as of 02/90

⁽³⁾	³⁾ As of 02/92 USA Only , ECE as of 01/93, certain burner bores countersunk 4°, prechamber volume increased to 11.37 cm³

⁽⁴⁾	⁴⁾ Engine 602.96 as of 05/92 with EGR, certain burner bores countersunk 4°

⁽⁵⁾	⁵⁾ As of 03/92 with EGR

⁽⁶⁾	⁶⁾ As of 04/94 all turbocharged engines, (standard prechamber of 11. 37 cm ³ ) prechamber volume and certain burner bores countersunk 4°