Valve Spring Failures On 3100 Engines Produced By Shin Caterpillar Mitsubishi (SCM) At Sagami Caterpillar

EXCAVATORS

TRACK-TYPE TRACTORS

INTEGRATED TOOLCARRIER

Problem:

There have been some reports of 7C-4273 Valve Springs breaking on 3114 (2ZF8900 - 2ZF9776), 3116 (1CK10790 - 1CK14860), and 3126 (3AK1 - 319) Machine Engines built at Sagami. The following charts identify the machines using these engines.

NOTE: The Machine Product Identification Number Ranges identified in the charts are approximate. There may be a few affected machines that are outside of these ranges.

The affected 7C-4273 Valve Springs were from an alternate supplier and these springs can be identified by a light yellow paint stripe. The affected 7C-4273 Valve Springs were used ONLY in the identified 3114, 3116, and 3126 Machines Engines manufactured in Sagami.

Solution:

None of the affected 7C-4273 Valve Springs was ever in the Caterpillar Parts System. Parts Service replacement 7C-4273 Valve Springs were manufactured by the standard supplier, and can be identified by a green, purple, or gray paint stripe.

If a valve spring failure occurs on an engine in the affected Product Identification Number range, Caterpillar recommends replacing all of the 7C-4273 Valve Springs in that engine. If there was no damage from the broken spring, it is not necessary to remove the cylinder head. A process for replacing the valve springs without removing the cylinder head in explained in Service Magazine; May 15, 1989; Page 5; "New Valve Stem Seal Used On Inlet Valves And Added To Exhaust Valves". The Parts Required include twelve 7C-4273 Valve Springs and a new valve cover gasket.

Caterpillar recommends visually inspecting the affected machines for valve spring breakage when performing a scheduled valve lash check, fuel timing check, or any time the valve cover of the engine is removed.

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