The orange line shows the direct path of constant, uninterrupted and continuous oil flow directly from the
pump to the factory's distributor shaft oil lube gallery:
(Above: the ID of the #1 cam bearing is grooved between the two holes so as to allow for continuous oil
In the next photo below, we can see that this gallery is 3/16-inch but has a countersink at the cam journal
that is 1/4-inch:
Use the step in the counterbore to locate the starting point of the new, dedicated distributor gear oiling
gallery. We can see in the photo below where the drilling (with a Dremel-style drilling tool) has started
the at precisely 12 o'clock and angled toward the location of the distributor gear:
Use extreme precision and double-check your angles and estimated exit hole to the distributor
gear, then drill with a high quality 1/16-inch drill bit. Use a 1/16-inch collet in a Dremel-style drilling tool and set
rpm to max (about 20,000 or so). Using the high speed Dremel, the drill will begin to penetrate the block almost effortlessly.
We do not recommend using a typical handheld electric power drill because the slow drilling
speed (about 750 rpm) is not suitable for this drilling application of the hard cylinder block material. Excessive force
on the tiny drill bit at these slower speeds will cause the bit to flex, overheat, and possibly break off in the
block as it exits the other side of the block material. In the photos below, the bit has been left in
the newly drilled (by Dremel) dizzy gear oil gallery so as to show proper angle and how perfectly this works:
In the above photo, note that the drill bit shank actually contacts the lower edge of the 1/4-inch countersink.
This emphasizes how tight one needs to negotiate drilling in order to get the proper angle and point the gallery high
enough to squirt oil onto the gear teeth and not end up breaking through below the gear.
Below is the photo
of the new dedicated distributor gear oiling gallery:
Finally, below is a picture of another block with this modification that has a little bit of gear wear on
it. The gear wear enables us to see that the new gallery breaks through at a location that will certainly spray the teeth
with oil and/or completely coat the teeth with the meshing of the cam gear.
Back to Top
The location of this newly added gallery is before any other pressure loss in the engine from the mains,
lifters, etc., so it is not believed that a tiny 1-inch long, 1/16-inch diameter gallery is going to be cause
for significantly reduced oil pressure. The oil pump's bypass spring corrects for this tiny but important gallery addition.
And it's small size--in conjunction with the constant 50-80 PSI of oil behind it--should make it more of a jet/squirt right
onto the dizzy gear.
Also, if you install roller cam bearings, their instructions call for grooving the block at the
cam journal between the two holes (because the gallery between the two holes is eliminated along with the standard bearing). Therefore,
this mod still works. Grand total expenditure: $1.89 (for the new drill bit).
Once again, drill angle is critical,
so double check your positioning.
And there, you have a dedicated distributor gear oilong gallery.