wrote:
I don't know what to do about this . . . hoping the collective wisdom
here might have some ideas. For the last 3 months or so, after every
flight, there are small streaks of oil on the inside of the lower
cowling on my 67 'Hawk . . . if I don't wipe them up, they drip down on
the tire of my nose gear. My mechanics have replaced all 6 rocker box
covers and gaskets, and re-flared the push rod tubes. I have spent
almost $1000.00 so far and it's still leaking. It holds pressure just
fine . . . my mechanics are now suggesting replacing all the push rod
tubes, but I get the feeling they are just guessing.
Any ideas?

www.Rosspilot.com

I agree with Kobra. I went through the same thing with my 0-300 and was
able to confirm (with great effort I might add) that the through bolts
are leaking. My mechanic confirmed that the 'O' rings in the case
halves do harden with age and the holes terminate outside the cylinder
seal. This is where the oil leaks, from under the cylinder at the
bolts. Looks like the push rod tubes and will drive you crazy. Since
giving up I am OK with flying a drippy plane. Keeps the belly from
corroding I figure. I have found that the absolute best way to find
leaks is the dye that shows up under a 'black light' (the ones that
glow yellow are my favorite) after a through cleaning. I seem to
remember the stuff being available on Ebay.

Jim