Vortech 1994-1995 7.4L TBI Truck/SUV - Manual (Page 12)

P/N: 4GC020-010
©2001 Vortech Engineering, LLC
All Rights Reserved, Intl. Copr. Secured
15SEP01 V1.1
(88-95 GM Lt Trk(4GC))
7/8" TO REAR
OF BOLT
OIL PAN
OIL FILTER
PUNCH HOLE THROUGH
DOWN 3"
3. OIL DRAIN LINE
A. Raise the front of the vehicle and support with
appropriate jack stands.
B. To provide an oil drain for the supercharger, it is
necessary to make a hole in the oil pan. It is best
to punch the hole rather than drill. Remove paint
around the hole area so that it does not flake into
the pan.
C. Make a mark on the oil pan on the driver’s side
ahead of the oil filter. The mark should be 3"
below the bolt flange and rearward of the fourth
bolt 7/8". (See
Fig. 3-a.) You may choose a
different place, if necessary; however, take care
not to damage any internal parts. The drain
hose should gradually drop with no dips or kinks
and should be above the oil level.
D. Use a small center punch to perforate the pan
and expand hole. Switch to a larger diameter
punch and expand the hole further to approxi-
mately 9/16" diameter. Most punches are made
from hexagon material and may be placed in a
socket with an extension to make this procedure
easier.
E. Tap the hole with a 3/8" NPT tap approximately
1/4" deep. Pack the flutes of the tap with heavy
grease to catch and hold the chips. Once the tap
is removed, it must be cleaned and repacked
before tapping resumes. Use a small magnet to
check for any stray chips in the threads after
completing the tapping procedure.
F. Thoroughly clean the threaded area with ac-
etone or other solvent. Apply a small amount of
silicone sealer to the new threads. Apply a small
amount of silicone sealer to the threads of the 3/
8" NPT hose fitting and secure in hole. Make
sure a seal is formed all around the fitting. Allow
sealer to cure completely.
G. Route the line forward along the top rail of the oil
pan and secure to the oil cooler line with the tie
wraps provided. Temporarily cover end of hose
and secure out of the way. The return is a gravity
drain and should be routed to provide a gradual
drop.
H. Drain and replace engine oil and change filter.
NOTE: This method of rolling over the lip of
the hole and tapping works well if
CAREFULLY done and should cause
no problems.
Fig. 3-a
2