PSP FOR INSTALLATION OF NEW LONGER VALVES IN 3304 AND 3306 NATURAL GAS ENGINES Caterpillar

PSP FOR INSTALLATION OF NEW LONGER VALVES IN 3304 AND 3306 NATURAL GAS ENGINES

Usage:

@media screen { div.divFooter { display: none; } } @media print { div.divFooter { position: fixed; bottom: 0; right: 0; } }

Caterpillar: Confidential Yellow

PSP FOR INSTALLATION OF NEW LONGER VALVES IN 3304 AND 3306 NATURAL GAS ENGINES

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.


SUPPORT PROGRAM FOR INSTALLATION OF NEW LONGER VALVES IN 3304 AND 3306 NATURAL
GAS ENGINES, 1105, 1100, PS0255
U-56
C-55
NOTE: Replace Service Letter (PS0255) dated August 28, 1985 with this revised
Service Letter. See changes denoted by (right arrow).
This Program can only be administered after a failure occurs. Contingent
damage will not be allowed. The decision whether to apply the Program is made
by the dealer. When reporting the repair, use "PS0255" as Part Number and
"7755" as Group Number.

Termination Date

(right arrow) December 31, 1986

Problem

The exhaust valves in the following 3304 and 3306 Natural Gas Engines can stick
open during operation. The cause of this is a build up of dried, hardened oil
in the valve guide.
New longer valves valve guides, spring spacers and rod assemblies (push rods)
along with several other parts are now (right arrow) used in production on
these engines. A remanufactured cylinder head with the new components is
available for the 3306 Natural Gas Engine.

Affected Product

Model  Identification Number
3304 Natural Gas Engine 37Y506-847, 849, 850, 852-979,
981-985, 987-997, 999, 1001-1017
3306 Natural Gas Engine 7Y291-2040, 2042-2051, 2053-2057,
2059-2062

Parts Needed

The following parts should be installed only if the exhaust valves on the
engine are sticking.
3304 Natural Gas Engines
4 - 7W7491 Valve (Exhaust)
4 - 7W7490 Valve (Intake)
8 - 7W7489 Guide
8 - 7W7488 Spacer (Spring)
1 - 7W7537 Cover Assembly
4 - 2H3756 Bolt (Head)
1 - 7W7480 Dowel
8 - 2W7047 Rod As.
2 - 7W7484 Bracket (Middle)
1 - 7W7483 Bracket As. (Front)
1 - 7W7479 Bracket (Rear)
1 - 8M4448 Seal
1 - 6V2502 Valve Grinding
Gasket Kit
(right arrow) 3306 Natural Gas Engines
1 - 0R1371 Cylinder Head
Grp. - Remanufactured
1 - 7W7539 Cover Assembly
6 - 2H3756 Bolt (Head)
1 - 6V2981 Valve Grinding
Gasket Kit
1 - 8M4448 Seal
1 - 6V1279 Aftercooler and Aftercooler Lines Gasket Kit
(if applicable)
1 - 7W7483 Bracket Assembly
(Front)
1 - 7W7479 Bracket (Rear)
12 - 2W7047 Rod Assembly
1 - 7W7480 Dowel
4 - 7W7484 Bracket (Middle)

Action Required

If the exhaust valves on a 3304 or 3306 Natural Gas Engine are sticking open,
install the listed parts.
3304 Natural Gas Engines Only
The 7W7488 Spacers are used under the valve springs to maintain the correct
spring height.
The new valve guides are longer and must be installed to the dimensions shown
in the illustration. A 7S8859 Driver Assembly, 7S8858 Bushing and 7W7488
Spacer can be used to install the guides to the correct dimension. The 7W7488
Spacer is used under the 7S8858 Bushing when installing the valve guides.
3304 And 3306 Natural Gas Engines
The 2H3756 Bolts (Head) are longer than the existing bolts and are used with
the new rocker shaft brackets.
The 7W7539 and 7W7537 Covers (Valve) must be used because the new rocker shaft
brackets are taller.
The 7W7480 Dowel must be installed in the bottom of the 7W7479 Bracket. The
dowel must protrude 9.6 +/- 0.5 mm (0.38 +/- .02") from the bottom of the
bracket.
(SEE ILLUSTRATION) WARRANTY ALLOWANCES
(SEE ILLUSTRATION)

Parts Disposition

Handle the parts in accordance with your Warranty Bulletin on warranty parts
handling. When returning cylinder pack cores, follow your established shipping
procedures for remanufactured core returns.