Continental A65 engine mount

[Steve Ahrens]

A question if I may?

I need to replace the engine mounts in my Skinny Bird. I have purchased the mounts, together with new bolts and nuts. I’ve looked in various Continental engine manuals, but unable to find any information on how to install the mounts. Is it done by crush length or bolt tension? Can anyone tell me or direct me to the correct installation procedure of the mounts please?

I’ve attached a photo of my mount for reference.

Thank you in advance.

[Andy Gelston]

The bolt length looks correct, you want about 1/8" of vibration isolator showing. If you bought Superior isolators, expect them to crack around the edges, pronto. They're okay, they're just made of some compound that cracks along the exposed edge. The forward washer doesn't look stock though. The OD should be the same as the isolator. Yours looks too big. Continental's washers for this are crazy expensive, but there are the same ones, just not PMA'd, available through McMaster-Carr and similar industrial supply houses. I don't remember the dimensions, but can look them up later.

[Brett Lovett]

60-80 inch pounds torque (using a castellated nut) is what I've seen for other aircraft with the A65.  I think Continental had a service bulletin with torque tables that included this info, but I can't find it now.  

I also found this on Univair's website regarding installation on a Piper J3. https://resources.univair.com/docs/continental-engine-mount-bushing...

[Steve Ahrens]

Thank you Andy and Brett, very useful information.

The new bushes are Superior Andy. Not sure if I should do anything about replacing the washers? I could turn them down to size in the lathe?

Brett your attachment is very useful, thank you.

I don’t understand why I’m not able to find information in the Continental engine manual about the mounts, other than part numbers.

[Brett Lovett]

Steve,

I found this (attachment below) in the "Maintenance and Overhaul Manual With Spare Parts Catalog Models A50, A65, A75, A80 Continental Aircraft Engines" dated 2-15-48.  These older manuals contain information that for whatever reason Continental omitted from later printings.  

The parts listed in this manual for the installation are:

22387 - Bushing – Engine Mount (Rubber) - 8 per assembly
21530 - Washer – Engine Mount - 4 per assembly

Beyond that I believe it was left to the discretion of the airframe manufacturer.  Bolt length could vary by engine mount design, and some manufacturers added hardware such as the fiber washers used by Piper.  Even the direction of bolt installation can vary.  (I have a Piper PA-17 where the top bolts install from the rear, and the bottom ones install from the front, due to baffle placement.  I only know that because I have copies of the factory drawings showing it.  I don't think Piper ever published anything generally available to the owner or maintainer that includes any information about it.)


Steve Ahrens said:

I don’t understand why I’m not able to find information in the Continental engine manual about the mounts, other than part numbers.

[Steve Ahrens]

Great info Brett!

I went back to 2 different A65 manuals I have thinking I may have overlooked the spec, but you’re correct it’s not in there.

I appreciate your help!

[Gary Baca]

I'm in the same boat, I need to replace my motor mounts as well

[Steve Ahrens]

I’ve just finished replacing my mounts Gary, but haven’t run the engine up.

In addition to Brett’s info above, my local engine rebuild shop sent me a photo from a later Continental engine manual, X30010.

During assembly of the mounts I used some graphite powder to help the bolts slide freely through the rubber. I assembled the mounts using the original bolts, which were too long, then measured and ordered the correct length bolts. As Andy said, the original rubbers didn’t look too bad once removed. I did find that the bottom left mount is slightly out of alignment, which slightly deformed the rubber.