Curious what most are doing for running the oil pressure line. Are you using a flex hose with a firewall fitting. Or a short flex hose off the engine into a copper line running through a grommet at the firewall?
The original set up was a flex line off the engine to a hard line to the gauge. Of course the best way is a flex line from the engine to a pressure sensor. Then wires from the sensor to the gauge.
The original set up was a flex line off the engine to a hard line to the gauge. Of course the best way is a flex line from the engine to a pressure sensor. Then wires from the sensor to the gauge.
That is the best way IF you are going to depend on electricity for your oil pressure reading. Oil pressure being the most critical instrument in the airplane, it is safer not to use two systems to operate it. Use direct reading oil pressure for safety. Always use a flexible connection between a component (engine) which moves and a component (airframe) which does not.
Univair sells the Piper flex line that attaches to the engine that also acts as a restrictor and was originally attached to copper tubing to the gauge going through a grommet at the firewall.
I have done both AN fittings and a single #3 Aeroquip, and the original Piper style using auto brake line stuff. From what information I have, the auto parts are good to 5000psi; the Aeroquip to 600. Difference in cost is stunning.
The original restrictor was simply a brazed and drilled pipe to inverted flare fitting.
Original oil pressure line pictured on a 1946 J3 that had been in a barn since 1950 unmolested. Looks like the same oil pressure line with restrictor fitting that is in the parts manual and every other tube and fabric Piper I have worked on. I have never seen:
The original restrictor was simply a brazed and drilled pipe to inverted flare fitting.
WOW, since 1950 that's amazing. I once had owned a Cub that had been stored since the 60's, still had the original fabric on it. Had 1,000 hrs total time. At least it had been stored in a dry area, no rust. That poor girl above, definitely needs some TLC, but still what a find. Thanks for all the above info. I know Piper used the short flex line with hard tubing to the gauge, but I'm leaning towards flex hose and a firewall fitting. Thanks again.