[rjcthree]

I'm struggling tightening my oil fittings. They are -8 o-ring type 90deg elbows, genuine Lycoming parts for my H2.

I get them positioned, put the prescribed torque on the position nut, then try to tighten the-8, and they move. Even if I could prevent them from moving, the whole thing doesn't seem to have even the modest positional rigidity of NPT.

Any ideas? Rick 90432

 

[TS Flightlines]

Rick-

Take 2 wrenches. Tighten the main fitting until the oring is snug, then hold the fitting in place, ans use a second wrench to tighten the lock nut. The nut and washer will push the oring into the groove, and seal.
Tom

 

[Mark Burns]

Tight

Rick,
Tom is correct.
Sounds like you my not have it tight enough even though you are to "spec".

The O-ring is just for sealing. The position (locking) nut will be metal to metal against your engine when tight. If tight, it will be VERY difficult to move.

Double check that your threads in the engine are indeed ORB. (o-ring boss)
They will be straight threads, have a bevel at the top for the o-ring to seat in. And the surface for the position nut will be flat (milled).

Mark