Product Support Program For Replacing Piston Rings On Certain 3508 EUI Engines Caterpillar

Product Support Program For Replacing Piston Rings On Certain 3508 EUI Engines

Usage:

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Caterpillar: Confidential Yellow

NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.

NOTE: This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS8533" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

Termination Date

May 31, 1997

Problem

The piston rings on certain 3508 Engines, 776 and 777C Trucks may have sustained damage due to cold ambient temperatures during winter, frequent cold starts such as when trucks operate daily but less than twenty-four hours per day, engines started without the use of starting aids, and/or operation with the engine personality module 1084330 or earlier.

This combination can produce a high rate of rise of cylinder pressures during engine acceleration under load between the time the engine has come out of "Cold Mode", but prior to it being fully warm. This high rate of rise of cylinder pressure can damage piston rings to the point of plasma flaking off or possibly ring breakage. Fully warm engines or operation in cold mode does not produce high cylinder pressure rate of rise.

Affected Product
Model & Identification Number

776C (2TK1-86)

777C (4XJ1-779, 4XJ779-779)

NOTE: This program also includes 3508 EUI Engines (7YG1-1315), Reman 3508 EUI Engines (5TL1-120), 776B Tractors (6JC1-Up), 777B Trucks (4YC1-Up), 3508 MUI Engines (99W1-Up), and Reman 3508 MUI Engines (4ZL1-Up) in dealer exchange inventory, all if they have been converted to EUI and operated with the 1084330 Personality Module.

Parts Needed

Group 1

Engines with 9Y7027 Piston Crowns (Engines 7YG1 - 499)

1 - 3E8918 Gasket Kit (per cylinder)

1 - 7E2631 Gasket

1 - 7E6436 Gasket

^*6I2863 Skirt-Piston

^*8N1233 Ring-Piston

^*8N1234 Ring-Piston (rectangular)

^*8N7810 Ring-Piston (keystone)

^*7W2221 Ring-Piston

^*1106993 Cylinder Liner (wide flange)

^*1210463 Crown Assembly

^*If a 9Y7027 Piston Crown is reused, only use the 8N1234 Rectangular Intermediate Piston Ring. Do not use the 8N7810 Keystone Intermediate Piston Ring with the 9Y7027 Piston Crowns.

^*9Y7027 Piston Crowns can only be replaced if they are damaged due to a broken ring or measure non-reusable. If a 9Y7027 Piston Crown can not be reused, it must be replaced with a new 1210463 Piston Crown and a 6I2863 Piston Skirt. The old skirt will not fit the new 1210463 Piston Crown. The quantity of 6I2863 Piston Skirts must match the quantity of 1210463 Piston Crowns. Use only 8N7810 Keystone Intermediate Rings on 1210463 Piston Crowns. Do not use 8N1234 Rectangular Intermediate Rings with 1210463 Piston Crowns.

^*The quantity needed in the repair is the total number of cylinders with ring damage and the number of cylinders to be repaired before failure. It is the dealers option whether or not to repair cylinders that have not failed.

^*Cylinder liners are only allowed if they were damaged due to a broken piston ring.