CYLINDER HEAD AS 1720838 - Caterpillar

VALIGN=TOP COLSPAN="2" WIDTH="69%">PRODUCT SUPPORT PROGRAM FOR REWORKINGCYLINDER HEAD VALVE ROTATOR INTERFERENCE ON CERTAIN G3516 AND G3520 ENGINES
1120 PS41904
This Program can be administered eitherbefore or after failure. In either case the decision whether to apply theProgram is made by the dealer. When reporting the repair, use "PS41904"as the Part number and "7755" as the Group Number. If administered beforefailure, use "56" as the Warranty Claim Description Code and use "T" asthe SIMS Description Code. If administered after failure, use "96" as theWarranty Claim Description Code and use "Z" as the SIMS Description Code. The information supplied in this serviceletter may not be valid after the termination date of this program. Donot perform the work outlined in this Service Letter after the terminationdate without first contacting your Caterpillar product analyst. This Revised Service Letter replacesthe August 16, 2005 (Revised November 2005) Service Letter. Changes havebeen made to the Parts Needed section.TERMINATION DATE
August 31, 2007PROBLEM
The cylinder head rocker arm base needs to beinspected on certain G3520 engines. The cylinder head valve rotator couldinterfere with the underneath side of the rocker arm base. During the normalvalve recession process the rotator could recess high enough to make contactwith the base, damaging both and leading to possible valve failure. Theengines need to be inspected and adjusted if necessary.AFFECTED PRODUCT
Model IdentificationNumber
G3516 TJB101-109TJC817-819
G3516B GAS111-120
G3516C GZZ114-134
G3516E SLY106-109
G3520C B9P200-214CWW200-295, 299-300CWY200-221HAT200-204, 206-211GDB0001-37GHC150-152HEB103-104HEA101-102JBX100-101JBZ101MAD200-201
G3520E GHR150-152PARTS NEEDED
Qty
Part Number Description
* 2037859 O-Ring Seal* Order one seal per cylinder.ACTION REQUIRED
See the attached Rework Procedure. SERVICE CLAIM ALLOWANCES
Product smu/age whichever comes first Caterpillar Dealer Suggested Customer Suggested
Parts Labor Hrs Parts Labor Hrs Parts Labor Hrs
0-20,000 hrs N/A 100% 0 0 0 0
Allow an additional $500.00 for machiningcost. Labor should not exceed 45 minutes per cylinder.PARTS DISPOSITION
Handle the parts in accordance with your WarrantyBulletin on warranty parts handling.Attach. (1-Rework Procedure)Rework Procedure
Rotate engine and inspect when valves are fullyclosed. To determine whether the valves are fully closed refer to Testingand Adjusting (RENR5978-06), "Finding the Top Dead Center Position forNo. 1 Piston" and Testing and Adjusting (RENR5978-06), "Crankshaft Positionfor the Valve Lash Setting".
Using a 4.0 mm (0.157 inch) thickness gage placebetween the top of the rotator and the underneath side of the rocker armbase. (Refer to attachment #1). If the thickness passes thru the spacethe clearance is OK. Measure all four rotator positions for clearance.
If OK, you do not need to adjust this positionon the rocker arm base.
If the thickness gage will not go thru the spacebetween the rotator and the underneath side of the base, the rocker armbase will need to be machined.
To machine the clearance into the rocker arm base,the base needs to be removed from the cylinder head- (reference Disassemblyand Assembly manual RENR5980-07).
Machine the underneath side of the rocker armbase to the dimension from the clearance cut to the top of the base shouldbe 21.3mm +/- 1.0mm (0.838 +/- .039 inches) Reference Attachment #2 and#3.
Make sure the machined area is smooth and no roughedges are present; avoid potential stress risers that may initiate cracks.
Replace the base onto the engine (reference Disassemblyand Assembly manual RENR5980-07)
Re-assemble rocker arm shaft and adjust valvelash to proper spec.
Note: Reference Specification Manual (RENR5977-07)and System Operation Testing and adjusting Manual (RENR5978-06)
Illustration 1 Illustration 2 Illustration 3