In a message dated 6/26/2004 9:37:08 PM Eastern Daylight Time,
Putting in a freshly reground crank today I note that again, the rod journal
supply holes are poorly aligned with the supply groove in the main bearings
I dutifully chamfer the holes to provide maximum coverage.
I find your wording rather confusing, main, rod, etc...
I think I know what you're trying to say, however.
Anyway, the way I remember it is the oil gets pumped into the block oil
galleries. Amongst other destinations, they come to a hole in each main
area which is aligned to the hole in each main bearing. The main bearings are
fixed in location, the hole is always aligned.
The oil flows thru the hole in the main bearing and fills the continuous
(360 degree)groove and what doesn't leak past the crank/bearing surface
continues into the hole in the crank. From there it goes to the adjacent rod
bearing(s) and lubricates that area.
I don't think there is any significance of BDC alignment, but I could be
Enlarging/aligning the main bearing hole may be of help, but the flow is
limited by how much oil makes it by the main bearings to the sump and the rod
bearings to the sump. Maximizing the potential flow by enlarging/aligning the
holes is not a bad idea.
"cross drilling" the oil holes in the crank to enlarge these galleries is a
method to increase flow to the rods. Drilling the galleries in the block
ditto. (kinda like the external rocker feed to the head).
I haven't checked, but I would expect that the comp prep manuals deal with
Does this make any sence?
74 Spitfire, 71 Stag
"Reality... it's not what you think"
Clark W. Nicholls
fax: 419-844-7564 (yes, 419 provided free by efax.com)