Problem With Spark Plugs In G300 Engines{1550, 1555, 1558} Caterpillar

Problem With Spark Plugs In G300 Engines{1550, 1555, 1558}

Usage:

G399 49C

Engine:: G333B (S/N: 84B1-UP); G333C (S/N: 68D1-UP); G342 (S/N: 71B1-UP); G353 (S/N: 64B1-UP); G379 (S/N: 72B1-UP); G379A (S/N: 72B1-UP); G398 (S/N: 73B1-UP); G399 (S/N: 49C1-UP)

Introduction

The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use a solution that is identified below.

The manufacturer of 2N-0553 Spark Plugs recently changed a manufacturing process. This caused the length of the spark plug to be shortened by approximately 1.52 mm (0.060 inch).

Problem

The shortened length allows the insulator of the 7W-8666 Plug Wire Assembly to contact the case of the spark plug before the wire clip can fully engage the spark plug's terminal nut. This causes arcing to occur between the wire clip and the terminal nut. The engine may be unable to pull load.

Solutions

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Illustration 1	g01445813
Section view of the spark plug (X) Distance between the contact surface for the spark plug gasket and the end of the terminal nut

Refer to Illustration 1. Measure distance "X" before installing the spark plug. if the distance is longer than 38.1 mm (1.5 inch), the spark plug is acceptable for use. If the distance is shorter than 38.1 mm (1.5 inch), use one of the following solutions:

Shorten the Insulator of the 7W-8666 Plug Wire Assembly

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Illustration 2	g01445897
Section view of an insulator

Refer to Illustration 2. Shorten the length of the insulator in order for the wire clip to fully engage the terminal nut.

Install a Longer Terminal Nut Onto the Spark Plug

Replace the terminal nut with a longer terminal nut. If you have not received a supply of longer terminal nuts, contact the "Gas Engine Customer Service" in order to obtain longer terminal nuts. Provide the following information: