User Manual

200 BENCH PROCEDURES
Page 5-61
Improved “Fast Ratio” Auxiliary
Driveshaft
An improved “fast ratio” auxiliary driveshaft
assembly and oil pump assembly are in current
production engines (effective February 27, 1992,
serial No. 2E1233) and are available for service.
These arrangements increase operating oil
pressure by approximately 25%.
앫 Current “fast ratio” oil pump:
— With rear sump, part No. 315GC459AM
— With front sump, part No. 315GC459AM2
— Drive gear (12 teeth), part No. 683GB284
앫 Former “standard ratio” oil pump:
— With rear sump, part No. 315GC460AM
— With front sump, part No. 315GCA460AM2
— Drive gear (13 teeth), part No. 683GB287
Do not mix “fast ratio” and “standard ratio”
components. Serious damage may occur.
Short (quarter) blocks are stamped with the date
of manufacture on the right rear side pad
(for example, “2G”: 2
G =1992, March). Short
blocks stamped with “2G” or later (2H, 2K, 2L,
etc.) are equipped with a 1.5 fast ratio auxiliary
driveshaft assembly. It is critical that the matching
oil pump also be fitted with a 1.5 fast ratio oil
pump driveshaft gear.
A noncurrent 1.3 standard ratio E7 oil pump can
be reused in combination with a 1.5 fast ratio
auxiliary driveshaft assembly; however, several
steps are necessary to modify the pump.
Refer to Figure 5-74.
1. Obtain a 1.5 fast ratio oil pump driving shaft
gear (683GB284).
2. Restamp or etch new number on oil pump
housing.
— “459M” on rear sump oil pumps
— “459M2” on front sump oil pumps
Figure 5-74 — Marking Oil Pump
3. Install a 1.5 fast ratio oil pump driving shaft
gear on an old E7 oil pump. Torque retaining
nut to 60 lb-ft (81 N•m). Torque cylinder
block mounting screws to 40 lb-ft (54 N•m).
It is possible to bolt a current 1.5 fast ratio oil
pump driving gear in an engine with a noncurrent
1.3 standard ratio auxiliary driveshaft gear;
however, serious damage will occur.
It is not
physically possible to bolt a noncurrent
1.3 standard ratio oil pump driving gear in an
engine with a current 1.5 fast ratio auxiliary
driveshaft gear.
200590a
STEEL STAMP
LAST 4 DIGITS OF
PART No."459M/M2"
IN THIS AREA .125
LETTERS
(BOTH VARIABLES)
459M
5-101.bk Page 61 Friday, March 17, 2006 11:05 AM