Questions:
- What's *supposed* to be on an O-360-A3A in a PA-28?

When we removed the air conditioning on our Cherokee, I got my wake up
call as to how little Lycoming and Piper knew about what they installed
on these airplanes. The parts manuals conflicted with the microfiche at
the dealer which conflicted with what was actually installed on our
airplane. So, finding out which part was "right" was a challenge.

I used a method that seems to work well "PIDBWA" (Parts identification
by walking around). I checked the part numbers on other models I saw on
the ramp and at other airports. When I see what was ACTUALLY INSTALLED
on similar airplanes of the same year (and it agrees with one parts
listing or another), that is what I go out and try to find. I had this
problem with the pulley bulkhead/ring gear. 2 different ring gear
pitches, 2 different pulley diameters, and several different belt
widths. Throw in the ones for air conditioned models and... GAAAAAA! I
just checked out the Cherokees on the ramp and instantly got the
consensus. Oddly, the parts installed on all the beasts matched NOTHING
of what the parts places were finding in their documentation.

One place to find this particular part is a little place in Texas called
"Bobby's Planes and Parts". O.K. quit laughing. This guy had every
conceivable pulley bulkhead/ring gear assembly in stock and actually
KNEW what he was talking about. His comment, "yeah the parts manuals are
all wrong". If you get in a jam finding one, I can scrounge up the phone
number and you can see if he is still in business.

Good Luck,
Mike