engine shock mount SDR

[cessnadriver]

SteveG-
Hello, I replaced the rear mounts. But I used the Barry mounts, at $75 per set, bought them from a Global salvage. It was the correct mount listed on the Barry Mount website. I did have a problem with them, I had to remove one of the washer under the nut but it was fine since the mount has a very thick material on the mount halves. My biggest problem was to get the damn bolts to line-up. I had to use all sorts of pry bars and adjust the hoist to get them in line.
Good luck, BILLS

[SteveG]

Thanks for the reply Bill. Yes, the work requires some patience but if you only remove one mounting bolt at a time you can maintain the overall alignment and it will go back just as it came out.

In examining the various shock mount part numbers it appears that the Lord J-9613-31 and the Barry 94017-01 are only used on Skymasters but are common to all model years. Therefore it would appear that the issue is confined to Skymasters but affects the entire fleet.

My conversation with the engineers at Lord has come to an abrupt halt. Seems that the lawyers or accountants or both have gotten to the engineering department and told them they cannot discuss this outside the company because in a schizophrenic about face the discussion turned on a dime from one of concern and intellectual curiosity to adamant denial.

I have to admit that I've been somewhat amazed that I can suggest that we are all operating with shock mounts that do not fit and are not performing as intended and that not one person has any comment or concern or any insight to contribute. But at least the issue is now documented in the forum for the use of any future search. Still, was it something I said? "I washed me face and hands before I come, I did." Eliza Doolittle.

[mshac]

This thread would be SO much more effective if it had PHOTOS!

Most of owners don't know the ins and outs of Lord mounts, halves, spacers, etc. because we've never dealt with them. If this issue is serious, please DOCUMENT it with photos, and copies of your emails with the Lord engineers. Thank you!

[wslade2]

Yes, photo helpful; have not ignored your post but carefully followed the wording to be sure I understand. I'm straining my memory banks. I did mounts a couple years ago. I'm pretty sure they were Lord mounts. And difficult to find a complete set. Getting them in was a wrestle. Seems like they bottomed out (as you're describing), everything looked ok and rubber was snug, so I called it a day there. Will look next time I am out at airplane and review manual too.

Are you saying once everything is tightened the rubber And the mount isn't snug? There's play?

[SteveG]

Hopefully these photos illustrates the issue graphically. The mount halves are designed to meet using a 0.620" spacer between them but my (our?) spacers are 0.770" thick leaving a 0.150" gap that cannot be made up. This issue also translates to the internal spacer which defines the amount of compression preload. Its length is designed to permit 0.410" of compression but because the mount halves never meet one would have to compress the mount 0.560" to tighten, a distance that cannot be realized with the length of threads available and is 37% greater than intended. As is, the mount never becomes a unified, stressed assembly as designed. The engine is just hanging off the upper mount half.

The thickness of the engine mount spacer, not including the flange which extends through the mounting plate, is compatible with the 0.310" flange of the two shock mount halves. I'm beginning to believe that the part was never designed correctly by Cessna and that this issue has existed from birth. Hard to fathom but I have no other explanation.

[mshac]

Thank you for the photos. What if the spacer were milled down .150?

[Kim Geyer]

I’ve changed many Skymaster engines over the years and I know they can be a pain.
Get your parts book and make sure your hardware is correct for each corner. The p/n for the mount is correct and they don’t touch each other in the middle of the mount.