Usage:
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 must be administered as soon as possible. When reporting the repair, use "PI3777" as the Part Number, "7751" as the Group Number, "56" as the Warranty Claim Description Code and "T" as the SIMS Description Code. Exception: If the repair is done after failure, use "PI3777" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.
NOTE: This Revised Service Letter replaces the May 29, 1995 Service Letter. Changes have been made to the Problem, Service Claim Allowances, and Rework Procedure.
Completion Date
November 30, 1995Termination Date
May 31, 1996Problem
The 6I2307 Exhaust valve springs may fail within the first 5000 miles of operation on certain 3116 Truck Engines.
Affected Product
Model & Identification Number
3116 (9GK22550-25760 9LN2620-2990 5RM227-275 (Military Vehicles Only))
Parts Needed
Dealers will need to order parts for this Program.
Action Required
See the attached procedure.
Service Claim Allowances
Parts Disposition
Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.
NOTE: MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.
Attach.
- (1-Rework Procedure)
Rework Procedure
The exhaust valve springs can be replaced without removing the cylinder head or fuel injectors on the engine. Illustration 1 shows how to fabricate an exhaust valve spring compressor tool of 6 mm (.25 inch) mild steel to allow for removal of the exhaust valve seal assembly.
TEPS dealers may obtain the spring compressor tool from their Caterpillar dealer.
Illustration 1
NOTE: Use two 153 mm (6.0 inch) long 8mm threaded rods along with two 9M1974 Washers and two 5P7970 Nuts with this tool to compress the exhaust valve springs.
To prevent the valves from falling inside the cylinders, the pistons should be at Top Dead Center (TDC). For 3116 Engines, pistons 1 and 6 are at TDC when the 8T0100 Bolt engages the timing hole. Turning the crankshaft 120° ( turn) CCW (as viewed from the flywheel) moves pistons 2 and 5 to TDC, and another 120° moves 3 and 4 to TDC.
NOTE: An easy way to know when the crankshaft has been turned 120° is to first mark TDC on the damper for pistons 1 and 6, then measure the circumference of the damper.Divide the circumference by 3 to determine how far apart the marks should be on the damper. Mark the damper accordingly.
1. Rotate the crankshaft until pistons number 1 and 6 are at TDC.
NOTE: Cover the push tube cavities with shop towel to prevent small objects from falling into the engine. Small objects could damage the engine.
2. Remove the rocker arms.
NOTE: Be sure to keep the rocker arms flat when removing to keep them from falling apart.
3. Use the two threaded rods to install the spring compressor plate to compress the spring for cylinder number 1. One of the rod holes align with the rocker stand bolt holes. The second threaded rod aligns with the intake manifold bolt hole next to the cylinder being worked on.
4. Use two 9M1974 Washers and two 5P7970 Nuts on the threaded rods to draw the compressor plate down on the valve springs. Keep the plate as flat as possible while compressing the springs.
5. Remove the exhaust valve retainer locks.
6. Remove the compressor tool, retainer, and the existing exhaust valve spring.
7. Discard the existing valve spring.
8. Install a new 6I2307 Exhaust Valve Spring. Compress the spring with the compressor tool and install the retainers.
9. Remove the compressor tool and threaded rods.
10. Install the intake manifold bolt. Tighten the bolt to a torque of 25 ± 7 N·m (18 ± 5 lb ft).
11. Repeat Steps 2 through 10 for the number 6 exhaust valve spring replacement.
12. Rotate the crankshaft 120°.
13. Repeat Steps 2 through 10 for the number 2 and 5 exhaust valve spring replacement.
14. Rotate the crankshaft 120°.
15. Repeat Steps 2 through 10 for the number 3 and 4 exhaust valve spring replacement.
16. Install rocker arms after all new exhaust valve springs are installed.
17. Check valve lash and injector timing per applicable Service Manual.
- 18. Install the valve cover.
19. Stamp "GK" on the block at the rear of the Engine Information Plate to signify this rework program has been completed. The Engine Information Plate is located toward the rear of the block mid way between the oil pan and cylinder head. See Illustration 2.
Illustration 2