Broken exhaust caused by worn lower engine mounts

Vernon Gregory @ Skyport sent me all new hardware, bolts, washers, and conical rubber Motor mounts. He even included 4 new cotter pins. I already had a lifetime supply leftover from working line maintenance for the airlines.

Changing the conical rubber bits out wasn’t terrible. The tedious part was the disconnecting and reconnecting the various goodies like the sheetmetal at the back of the engine and throttle cable to get enough slack.

I had never heard the recommendation to change them out every few years.

The bigger challenge was sourcing the new springs for heat transfer and figuring out how to simultaneously and permanently stretch both of them out to replace the old springs that had been terminally deformed when the exhaust broke.

Barrow or buy Harbor Freight engine hoist , remove cowl, , hang engine and take up weigh and go for it with new conical rubber dampeners

The old spring kept half the exhaust pipe from departing the aircraft. Needless to say it was unusable and apparently completely unavailable.

I found www.amazon.com/Handyman-Springs-Extensio...ps%2C107&sr=8-1&th=1

On amazon had the same basic wire size (wire thickness, inside and outside diameter)

I had to make a jig to stretch the wire out. The first time I didn’t use a jig and i didn’t work out very well

Then I used a 36 inch threaded rod, 2 nuts, and 2 large fender washers from Home Depot.

I bent the double loop end a bit so I could fit the end into a slot I cut into the fender washer. I also used safety wire to keep the end of the spring from departing the jig.

I tried putting the stretched springs in the oven for 1/2 hour @ 500 degrees. That didn’t work.

I took it to my welder who let me use his torch.

I found that it needs to be warmed up gently enough to loose the shinny off the spring and get an even spacing between the individuali loops.

If I were to do it again I would only stretch the spring out to 24 inches. Remember this spring started at 16 inches.

And when I installed the new springs on the exhaust pipe three wraps was too thick for the heat muff but 2 1/2 fit.

No 8130 for this item. It is not a safety of flight item and fits with ‘owner supplied part’.

I have the O200 engine that uses Lord mounts. New bushings going on when the engine gets back from the overhaul shop. They had been replaced about 500 hours ago. 

I read someplace that these should be replaced every 3-4 years.

These were probably on for at least a decade.