scsmith
Well Known Member
I have a couple of questions for the engine gurus before I dive in and clean my lycoming fuel injector nozzles.
First, installation torques.
The Lycoming service bulletin says to torque the nozzle body to 60 in-lbs, then continue to turn until the "A" on one wrenching flat is downward.
I have not found any torque specification on the 'b' nut for the fuel distribution line to the injector nozzle body. Recommendations?
Second, the thread on the nozzle body into the cylinder head appears to be a NPT pipe thread. A maintenance article I found from Kelly Aerospace recommends lightly oiling the threads prior to installation and torquing. !!BUT!! a pipe thread will leak if no thread sealant is used. Some people think that since a pipe thread is tapered, it seals when tight, but there is always a helical leak path around the root of the threads. I'm guessing its OK to just have that minute leakage?
First, installation torques.
The Lycoming service bulletin says to torque the nozzle body to 60 in-lbs, then continue to turn until the "A" on one wrenching flat is downward.
I have not found any torque specification on the 'b' nut for the fuel distribution line to the injector nozzle body. Recommendations?
Second, the thread on the nozzle body into the cylinder head appears to be a NPT pipe thread. A maintenance article I found from Kelly Aerospace recommends lightly oiling the threads prior to installation and torquing. !!BUT!! a pipe thread will leak if no thread sealant is used. Some people think that since a pipe thread is tapered, it seals when tight, but there is always a helical leak path around the root of the threads. I'm guessing its OK to just have that minute leakage?