The International Cessna 170 Association

What is the correct torque value for the oil sump quick drain with the copper crush washer? According to Continental SB96-7c the value is 15.8-17.5 ft/lbs, but I also found that for the copper crush washer the value for is 135 degrees of turn after contact. What should the torque value be in this application?

Thanks for the help!

Whichever method you use, don't back off the plug once you stop tightening it, torque it up, stop, and safety it.

I torqued it to 17 after looking at SB 96-7c and talking with my IA. After flying it this weekend I noticed it was still leaking pretty good from the sump drain threads. I went out there today and had a look at the threads and everything looked good with no obvious corrosion(the drain I removed looked good too). I drained the oil and left the plug out so I can get it nice and dry around the threads. Tomorrow I am going to use blue locktite and see if I have better luck. Previously I used the little packet of anti seize that came with the saf-air drain. I will also see if the 135 degree torque matches 15.8-17.5 and report back.

I am slowly getting a handle on all these oil leaks. After sitting out in the hot sun for years with no use, many of the seals and gaskets were pretty shot.

Mike,
It sounds like something else is going on with this leak. Lock tight on the threads should not be necessary as the crush ring seal you have been working with is out side of the threads.

Don't use Locktite. It is not the thing to do. Something else is a awry. Get input form your IA.

BTW a sump with a pin hole in front of the drain sump could look like a seep from the threads. If your talking the sump hole at the back that is not the usual place for sump rotting but it could happen anywhere.

If you have an oil leak that you are not sure of. One that might have serious consequences if allowed to progress unchecked. Do not fly the aircraft until you understand and correct the problem. Standard procedure: Oil leak. Thoroughly clean and inspect engine with qualified personnel. Perform ground run (in case of small GA engine at least 15-20 minutes with varying power settings. Check for leaks again. If still there, start trouble shooting with qualified personnel (cross threading? worn threads, correct parts, cracks/corrosion not visible to naked eye? Dye penetrant?) A pound or 2 of torque value is not going to show up as a leak. Some leaks may take more work. Sometimes they don't manifest until after an hour or so in service so you may end up having to fly a bit. I have seen what looked like annoying but persistent little leaks end up with an engine change A private pilot can do an oil change including filters/screens etc. The problem you describe calls for a qualified mechanic. Good luck and hope its not serious.

I might have misunderstood what happened here because maybe you did all that before flying. Its just that your threads sound as if you have been flying with a "pretty good leak" that is originating from where your oil supply is stored. Please don't take my advice the wrong way. It is directed at us all including yours truly.

You DID face the open-side/seam-side of the crush-washer toward the engine, correct?

Thanks George..... No more leak.

FYI, 17 foot pounds really didn't correspond with 135 degrees of turn. I stuck with the SB number.