Piper J3
Well Known Member
I’m just starting Annual Condition Inspection at 633TT and began by looking at engine mount standoff for cracks per SB-00023. Standoff looks good; however, further inspection of the main engine mount found a cracked tube at the lower left engine bolt. Two tubes are welded in a cluster at this location and upper tube is severed in half – lower tube looks fine. I suspect the failure is induced stress from welding. Perhaps the normalizing process wasn’t sufficient to equalize strain in the two tubes that form this joint.
So, even though the standoff passes inspection I will replace it as long as I have everything apart. I’m also going to do 5-year rubber hoses with High Performance Silicone Heater Hose, install new rubber engine mount isolators, and remove the fiberglass cooling shroud.
Good thing the US Congress is passing the COVID relief bill, it looks like my stimulus check should just about cover the cost of parts.
The photos below are my airplane and one in Australia with a crack recently discovered. The Australian RV-12 has crack in lower right main tube near the oil tank. Both failures have been reported to Van’s…
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So, even though the standoff passes inspection I will replace it as long as I have everything apart. I’m also going to do 5-year rubber hoses with High Performance Silicone Heater Hose, install new rubber engine mount isolators, and remove the fiberglass cooling shroud.
Good thing the US Congress is passing the COVID relief bill, it looks like my stimulus check should just about cover the cost of parts.
The photos below are my airplane and one in Australia with a crack recently discovered. The Australian RV-12 has crack in lower right main tube near the oil tank. Both failures have been reported to Van’s…
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