Hey Brian, thanks for digging out some Ford documentation on this. I
had previously noted on an 8BA camshaft that there was a tiny positive
oil feed provided up to the front end of its nose to lubricate the front
thrust area. The front bearing journal of the cam is drilled inward to
a central drilling which goes to the front end. The interesting part is
that the radial drilling does NOT register with the full pressure oil
passage in the cam that carries a lot of oil to the crank front main,
instead the drilling just faces a plain portion of the cam bearing
insert(the bulletin calls a bushing). So the oil that travels up the
camshaft center to the nose is just that escaping through the cam
bearing insert oil clearance, which on its way encounters the hole in
the rotating camshaft, and AGAINST CENTRIFUGAL FORCE goes up the hole
and thence forward. So the amount of oil that can do this won't be a
lot, but the engineers didn't want a lot of oil up there, just a steady
seep.
Now in my Ardun I have a early-style Isky steel billet flat-tappet cam,
with a bolt-on Flathead Jack nose to take the gear to drive the Vertex
mag in a late-style timing cover. And the early gears to thrust
backwards. So no drilling to provide oil up to the mag drive gears.
Since I figured the mag drive gears are heavily loaded by the power it
takes to spin the Vertex, compared with a dist., plus the weight of its
rotating magnet, when the revs jump up and down, I wanted plenty of oil
up there. So I adopted Ardun Doug's idea of drilling the front oil
gallery plug, I made the hole 1/32", which seems to have little or no
effect on the oil pressure at idle with 5w-30 oil. And I can tell that
plenty of oil is flying around inside there since a little of it makes
its way up the mag drive shaft and spits out of the (un-sealed) joint of
the mag and the timing cover at the top! And on examination the drive
gears are not showing excessive wear.
Next weighty matter to ponder will be whether my Vertex drive gears pull
the cam forward, while the cam gears pull it backwards. It's not a big
deal because there is visibly only a few thou clearance between the gear
on the cam nose and the thrust face on the timing cover. So if the cam
walks it can't be far.
Glad you came up with the Ford bulletin, Brian, good show! Cheers Bill
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