Engine - Block, Balance Shaft, & Front Case Changes

85mitsubishi02

SUBJECT:

DESIGN CHANGES - CYLINDER BLOCK, BALANCE SHAFT, AND FRONT CASE - 1.8L, 2.0L, 2.4L ENGINES
NO. STB-85-09-018

DATE December, 1985

MODEL 1986 Cordia, Tredia
Galant, Truck
PURPOSE

This bulletin describes design changes that were made to the cylinder block, balance shafts and front case assembly of the engines in the G6B family (1.8L, 2.0L, and 2.4L) shortly after the start of 1986 model production. Although the changes do not affect repair operations, they do change the appearance and interchangeability of the affected parts.
DESCRIPTION OF CHANGES

The changes are discussed in detail below.

FIGURE 1:

CYLINDER BLOCK AND BALANCE SHAFT BEARING

1. An oil hole has been added to provide direct lubrication to the right rear balance shaft bearing. This drilled hole is plugged with a 1/16" NPT plug which is visible from outside. See Fig. 1.

2. The balance shaft rear bearings now have a 6mm oil hole.

FIGURE 2:

BALANCE SHAFT

1. The front bearing of the right balance shaft has been widened by 6.5mm (see Fig. 2), and the oil holes have been eliminated from the balance shaft.

FIGURE 3:

FRONT CASE ASSEMBLY

1. The driven gear bearing has been lengthened to accommodate the longer balance shaft bearing, and the oil passage diameter has been increased. See Fig. 3.
INTERCHANGEABILITY OF PARTS

CAUTION: The new balance shaft cannot be used in an early block because the new shaft does not have an internal oil passage, and this would result in insufficient lubrication of the rear bearing and consequent bearing failure.

For details on parts interchangeability, please refer to MMSA Parts Bulletin No. 09-XX-12-85.