2000/08/01 Caterpillar

Engines:

G3606 (S/N: 3XF1-UP)

G3608 (S/N: 4WF1-UP)

G3612 (S/N: 1YG1-UP)

G3616 (S/N: 4CG1-UP)

Description of Change: New prechamber gaskets, prechamber assemblies, and ignition body assembly have been made available for use in all G3600 Engines in natural gas applications.

The new prechamber gaskets are made of a different material in order to better conform to the mating surfaces of the cylinder head, ignition body, and prechamber assembly. Some dimensions of the new gaskets are different. This improves the load distribution between the upper gaskets and the lower gaskets that are used in two-piece ignition body and prechamber assemblies.

The new ignition body assembly is for natural gas applications that have a 9:1 Compression Ratio (C/R). This new ignition body assembly combines the ignition body and the prechamber assembly into a single welded prechamber assembly.

Adaptable To: The Table and Illustrations identify the prechamber groups, group components, and applications. The Illustrations identify the effectivity of the prechamber groups.

Illustration 1	g00728348
This illustration shows the locations of gaskets, prechamber assembly, and ignition body for the two-piece design of the 110-5469 Prechamber Group for 9:1 C/R applications. The two-piece design of the 110-5469 Prechamber Group is effective with G3606 S/N:3XF1-215 , G3608 S/N:4WF1-142 , G3612 S/N:1YG1-183 , and G3616 S/N:4CG1-156 . (1) 173-7681 Chamber Body Assembly (Ignition Body) (2) 125-3848 Prechamber Assembly (3) 187-6614 Gasket (Upper) (4) 187-6613 Gasket (Lower)

Note: The new 187-6613 Gasket (Lower) and the new 187-6614 Gasket (Upper) are NOT recommended for applications that have corrosive components in the engine fuel supply. One example of a corrosive engine fuel supply component is H₂S.

Illustration 2	g00728528
This illustration shows the locations of the gasket and prechamber assembly for the single piece prechamber assembly design of the 110-5469 Prechamber Group for 9:1 C/R applications. The one-piece design of the 110-5469 Prechamber Group is effective with G3606 S/N:3XF216-UP , G3608 S/N:4WF143-UP , G3612 S/N:1YG184-UP , and G3616 S/N:4CG157-UP . The new gaskets are effective with G3606 S/N:3XF268-UP , G3608 S/N:4WF165-UP , G3612 S/N:1YG202-UP , and G3616 S/N:4CG187-UP . (4) 187-6613 Gasket (Lower) (5) 169-5456 Prechamber Assembly

Note: The one-piece prechamber assembly is NOT recommended for landfill/digester gas applications. The one-piece prechamber assembly is NOT recommended for high efficiency 10.5:1 C/R applications. These applications will continue to use the two-piece prechamber assemby.

Illustration 3	g00728550
This illustration shows the locations of the gaskets, prechamber assembly, and ignition body for the 125-3805 Prechamber Group in 10.5:1 C/R applications. The 125-3805 Prechamber Group is effective with G3612 S/N:1YG202-UP and G3616 S/N:4CG187-UP . (1) 173-7681 Chamber Body Assembly (Ignition Body) (2) 125-3848 Prechamber Assembly (6) 187-6615 Gasket (Upper) (7) 174-0130 Gasket (Lower)

Illustration 4	g00728576
This illustration shows the locations of gaskets, prechamber assembly, and ignition body for the 117-4911 Prechamber Group that is used in Low BTI (Landfill and Digestor) applicaitons. The 117-4911 Prechamber Group is effective with G3606 S/N:3XF268-UP , G3608 S/N:4WF165-UP , G3612 S/N:1YG202-UP , and G3616 S/N:4CG187-UP . (2) 125-3848 Prechamber Assembly (6) 187-6615 Gasket (Upper) (7) 174-0130 Gasket (Lower) (8) 173-7663 Chamber Body Assembly (Ignition Body)

The new 187-6615 Gasket (Upper) is for use in high efficiency applications and Low BTU (landfill and digestor) applications. This gasket is made of the same material as the former 175-6574 Gasket (Upper), but the 187-6615 Gasket (Upper) has a larger sealing surface area. The 174-0130 Gasket (Lower) is still available for the joint between the head and prechamber assembly. This gasket also has a larger sealing surface area.

The former 175-6573 Gasket (Lower) and former 175-6574 Gasket (Upper) have been cancelled.