90 degree fittings are acceptable.
As you know the Lycoming engine pumps use special fittings with a O-ring seal rather than a taper thread. These fitting come in both straight and 90 degree versions.
What's the torque value on end that goes into the fuel pump?
Michael-
I have never heard of the fitting coming loose on a Pitts. I do know of two airplanes, I think both Rockets where the fitting came loose and started an inflight fire. One event was fatal to one of the two on board. The 90 degree fitting allows one to reach in and check the integrity any time the top cowl is off. With a straight fitting you will need to put a wrench on it, much more difficult depending on the individual installation.
I tighten the jam nuts pretty tight. It would be a real ordeal to get a torque wrench in there after the engine is on the airplane.
...the straight fitting that goes into my fuel pump was only finger tight. ...Mine was a straight fitting and there is no jam nut. Everything else was tight and the O ring looked good.
Just to make sure everyone is using the right terminology here...there are "straight" AN fittings, 90 degree AN fittings, straight *threads* on NON-AN fittings.
The Lycoming fuel pumps, as noted above, take "O-ring Boss" straight thread fittings, which can be straight (no jam nut, since it's not necessary, obviously), 45 and 90 degrees (both with jam nuts). All have straight threads on the fuel pump end, AN flare on the other...
I'm sure this is patently obvious to everyone, but there may be some new-to-engine folks here who might be confused with the various use of "straight" and since fuel systems are critical...
Confusing?
I have an O-360 lycoming and I'm assuming it's a Lycoming mechanical fuel pump but being I didn't build the plane and never thought of the pump possibly being different, didn't check (but will) for now I will assume it's a Lycoming.
It was the straight thread butting up onto the "O-ring Boss" that was finger tight. Maybe it does need a jam nut? Maybe it wasn't tightened up when put together? Maybe the o-ring characteristic changed over time relieving pressure on the straight thread butting up onto it?
It doesn't sound like it's a common problem but it has been reported a few times on here so it does raise an eye brow, at least it raised mine as the consequences of this are serious and have been serious in the past to a few people.
Tim
So far it appears I have the KB-000 fitting with the O-Ring. The pump I'm sure is a Lycoming but I will verify that in the morning.
....
Tim