• The Biplane Forum is a large global active community of biplane builders, owners and pilots. From Pitts to Skybolts, to older barnstormers, all types are welcome. In addition to our active community, our content boasts exhaustive technical information which is often sought after for projects and maintenance. This information has accumulated over the 12+ years the forum has been in existence.

    The Biplane Forum is a private community. Subscriptions are only $49.99/year or $6.99/month to gain access to this great community and unmatched source of information not found anywhere else on the web. We are also a great resource for non biplane users, since many GA aircraft are built the same way (fabric and tube construction). Annual membership also comes with two BiplaneForum.com decals.



Proper Torque for O-320 exhaust nuts.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
May 24, 2012
Messages
1,826
Reaction score
604
Location
Cameron Park, CA. (O61)
I am replacing the gaskets on my exhaust. I tried to research what the proper torque value is for the 5/16-18 nuts that hold the exhaust stacks onto the cylinder exhaust port studs. A lot of people were confusing the stud torque value with the nut torque value. In any case, I didn't have much confidence in what I was reading since the values were ranging from 160 - 210 in. lbs.

A Lycoming service limits and torque recommendation manual listed 160-180 in. lbs. and technicians from Mattituck, ECI, and Aircraft Engines Inc. are listing 204 in. lbs.

It seems over torquing these nuts would be very problematic due to the heating and cooling cycles, as well as potential warping to the exhaust stack flange which would result in an exhaust leak.

My inclination is to start with 160 in. lbs. and see how it goes before increasing the torque.

Can anyone speak from experience here on what would be the best technique?

Thanks,
Glenn
 
Last edited:

Latest posts

Back
Top