Piper J3
Well Known Member
Earlier this year I installed Aircraft Specialty Conductive Teflon Fuel hoses on my early SN RV-12 to begin compliance with Rotax 5-year rubber hose replacement. Now I?m changing out the oil lines with Aircraft Specialty Conductive Teflon hoses. This will complete all rubber hose change-out with exception of coolant hoses, which I will monitor and plan for replacement in the near future.
I bought my 12 as a flying airplane three years ago from the original builder with 48TT. On my first thorough inspection of the engine I noticed the 90-degree fitting on the crankcase drain was almost touching the muffler. I estimate the clearance to be no more than 1/8?. I suspect there is a tolerance stack in the exhaust components and each installation is a little bit different. I surfaced my concern in a VAF thread and was told, ?That?s the way it is.? I now have 400TT and still don?t like it?
Aircraft Specialty offers the Teflon drain hose in two different configurations. The configuration that I chose comes with an OEM Rotax Banjo fitting to provide extra clearance from the muffler. The Banjo fitting requires safety wire to secure it. Clearance to muffler is now ~ ??. This option is the more expensive of the two replacement options due to the added cost of the Banjo fitting, however, I value my safety and piece-of-mind. Even with the added cost of the Banjo fitting, the Aircraft Specialty Conductive Teflon hose kit is significantly less expensive than purchasing the OEM hoses from Rotax/Vans.
The crankcase drain line can be installed dry but the two remaining supply lines must be filled with oil during assembly so air doesn?t get into the oil pump and hydraulic valve lifters. This is simple to accomplish by first installing the hose fitting at the lowest end and then pouring oil into the raised hose before installing and tightening the upper end fitting. When oil hose installation is complete, I remove the upper sparkplugs and hand turn the engine until the EMS shows positive oil pressure. A ground run of the engine with the cowling removed is necessary to assure no oil leaks.
Original 90 degree fitting with ~ 1/8? muffler clearance?
New Banjo fitting with ~ ?? muffler clearance?
Safety wire through eyelet on bottom of crankcase?
I bought my 12 as a flying airplane three years ago from the original builder with 48TT. On my first thorough inspection of the engine I noticed the 90-degree fitting on the crankcase drain was almost touching the muffler. I estimate the clearance to be no more than 1/8?. I suspect there is a tolerance stack in the exhaust components and each installation is a little bit different. I surfaced my concern in a VAF thread and was told, ?That?s the way it is.? I now have 400TT and still don?t like it?
Aircraft Specialty offers the Teflon drain hose in two different configurations. The configuration that I chose comes with an OEM Rotax Banjo fitting to provide extra clearance from the muffler. The Banjo fitting requires safety wire to secure it. Clearance to muffler is now ~ ??. This option is the more expensive of the two replacement options due to the added cost of the Banjo fitting, however, I value my safety and piece-of-mind. Even with the added cost of the Banjo fitting, the Aircraft Specialty Conductive Teflon hose kit is significantly less expensive than purchasing the OEM hoses from Rotax/Vans.
The crankcase drain line can be installed dry but the two remaining supply lines must be filled with oil during assembly so air doesn?t get into the oil pump and hydraulic valve lifters. This is simple to accomplish by first installing the hose fitting at the lowest end and then pouring oil into the raised hose before installing and tightening the upper end fitting. When oil hose installation is complete, I remove the upper sparkplugs and hand turn the engine until the EMS shows positive oil pressure. A ground run of the engine with the cowling removed is necessary to assure no oil leaks.
Original 90 degree fitting with ~ 1/8? muffler clearance?
New Banjo fitting with ~ ?? muffler clearance?
Safety wire through eyelet on bottom of crankcase?