CARRIER AS 7T8518 - Caterpillar

ENGINES
ALL CATERPILLAR MACHINES POWERED BY 3114, 3116, AND 3126 ENGINES;
ALL 3114 AND 3116 INDUSTRIAL, MARINE, GENERATOR SET AND TRUCK ENGINES;
ALL 3126 INDUSTRIAL, MARINE, AND TRUCK ENGINES)Problem:
There have been reports of intake valve failures that have resulted from contact between the intake valve and the piston. This contact is the result of the new 130-9004 Intake Valve Seat Inserts being incompletely ground after installation in the cylinder head. If the valve seat insert in not correctly ground, the intake valve will NOT have the correct recess in the cylinder head. This could allow contact between the piston and intake valve and result in engine damage.Solution:
The new 130-9004 Intake Valve Seat Insert is designed to provide a wider seating face when fully machined. But this new insert requires more machining to maintain the same distance from "head of valve to the cylinder head face", and therefore piston to valve clearance.* It is CRITICAL that the "head of the valve to cylinder head face" dimension be within the current specification of 1.13 to 2.05 mm (.044 to .081 in) REGARDLESS OF THE VALVE SEAT INSERT USED.* To achieve this, the outside diameter of the seating face on the 130-9004 Intake Valve Seat Insert should be machined to a diameter of 47.0 mm (1.85 in). * For all previous intake valve seat inserts, the outside diameter of the seating face on the insert should be machined to a diameter of 45.9 mm (1.81 in). ALL engines and all cylinder heads in the process of getting reworked as per Product Support Program PS4486, must be checked before completion of PS4486 to insure that the intake valve recess is within the specification of 1.13 to 2.05 mm (.044 to .081 in). If the intake valve recess is not within this specification, the cylinder heads must have the intake valve seats reground to achieve the specification.COPYRIGHT 1998 CATERPILLAR ALL RIGHTS RESERVED