BANTAM PISTONS AND RINGS (EGGE HEREIN)
Q: As I may have mentioned to you, I have had trouble with
the Hollywood engine (discussing a three main...engine numbers
above 65500) using oil, smoking, fouling plugs, etc since
I have installed new pistons and rings from Egge. There was some
confusion as to which way the bevel on the compression rings went,
(up or down) as Egge didn't seem to know (or care) after two calls
to them. (Note, Egge Engeneering in Los Angeles makes pistons
and rings for Bantams which are "cam ground" which is
to say, slightly oval as the original pistons were. Needless to
say these are not a high demand item, but we are lucky to have
them available at all).
A: According to the factory drawings for the piston rings, the small step (you called it a bevel) faces toward the TOP of the piston for #1 compression ring, (drawing #A-8868), and faces DOWN toward the bottom of the piston on #2 compression ring (drawing # A-8874). The bottom ring is the oil ring. (drawing # A-8880). the ring is symetrical, so it can go either way.
Q: I think now that my problem may be that there is no holes in the pistons in the oil ring slot. The Bantam tech info says there are holes in the piston, but where, what size and how many.
The Bantam piston drawing is C-3679. This was originally for
the 2 main Bantam. The 3 main Bantam has the same pistons, only
they are larger in diameter and have some different dimensions
as described on drawing A-8832 (this updates the piston for the
3-main engine). I am sending you xerox copies of the aforementioned
drawings. The only one I need back from you, is the larger drawing
C-3679 of the piston. You may keep the copies of the small A size
drawings. You may copy the larger C-3679 drawing, if you wish,
but I do need my copy of the C-3679 returned to me. Please return
it to me promptly. I have a habit of forgetting to whom I loaned
what. Note on
section C-C it says "7/64 drill, 8 holes spaced as shown
in #3 groove" . In section C-C you will see the spacing of
the holes. Starting at the vertical centerline of the piston at
the 6 o'clock position, and going clockwise, the first hole is
20 degrees from the 6 o'clock position, the next is 40 degrees
from the first hole, the third hole is 60 degrees from the second
hole, and the fourth hole is 40 degrees from the third hole. This
completes the location for four holes on one half of the piston.
The other half of thepiston is symetrical with the first half.
A :I called Egge yesterday, and they say there are usually holes,
but
promised to find out and call back. They never did. Norm, I would
appreciate any info you might have. I turned the second compression
ring with the bevel down, and it smokes much less. Crotty says
I probably should not run the engine this way. What do you think?
I did finally get a call from Egge and they say that there should be holes in the oil ring groove, so I will be drilling these in the pistons in a few days. I will keep you advised of the outcome. Right now with the top compression ring installed with the bevel up and the second installed with the bevel down, it runs well, and smokes a little, but seems to run a little hotter.
I call it a bevel as the ring looks like the one inner corner
is cut off
at about a 45 degree angle. Egge says both bevels should be installed
up. Egge also says that instead of drilling holes in the piston,
a slot
could be cut in several places in the oil ring slot. As with a
hack saw.
I think I will go for the holes as per the factory drawing.