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RV-14 IO-390-EXP119 ENGINE EXHAUST

Jetmart

Well Known Member
Section OP-62 calls for supporting the tail pipes off the motor mount instead of the sump. Mounting to the sump allows the exhaust to move with the engine. Is there any longer term concerns mounting the exhaust to the fixed motor mount? Have other RV models mounted off the mount?

The OP-62 option is too new to have any long term experience with exhaust issues.
 

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I have 700 hours on my RV-14A with a Vetterman trombone exhaust (2 x 2-in-1) with the exhaust mounted to the engine mount and not the tunnel. Time is split between a Superior XP400 and Lycoming IO390. I have had minor issues with the exhaust hanging hardware - broken adel clamps (you will need to go to steel clamps) and a single failure of a crushed end hangar tube. There is a lot of movement during the dog-shake at start and shutdown. The crossover exhaust on the EXP119 will of course be different.
 
I tried many other things but finally did it the way Vetterman recommended - hanging from the engine - and it's working fine. I used double good quality "hose clamp" instead of one, with longer tubes and longer hose. One pic below and more here: http://www.rv8.ch/engine-photos-after-test-flights/

IMG_1643.jpg

https://www.google.com/search?q=rubber+exhaust+hanger&tbm=isch

If you look at the search above, you will see lots of interesting rubber mounts that the car guys use. I bought about 10 different types from the junkyard trying to find a better way. I'm sure that there is a better way, particularly if you are using the engine mount to support the exhaust pipes. I was not smart enough to figure one out.

The motion of the engine during startup and shutdown will be mostly rotational, and looking at the OP-62 you linked that motion should be "ok" with the suggested mounting method.
 
With the rotational movement in mind what is the minimum distance from the firewall or bottom of fuselage should the tail pipes be mounted?
 
I tried many other things but finally did it the way Vetterman recommended - hanging from the engine - and it's working fine. I used double good quality "hose clamp" instead of one, with longer tubes and longer hose. One pic below and more here: http://www.rv8.ch/engine-photos-after-test-flights/

View attachment 10540

https://www.google.com/search?q=rubber+exhaust+hanger&tbm=isch

If you look at the search above, you will see lots of interesting rubber mounts that the car guys use. I bought about 10 different types from the junkyard trying to find a better way. I'm sure that there is a better way, particularly if you are using the engine mount to support the exhaust pipes. I was not smart enough to figure one out.

The motion of the engine during startup and shutdown will be mostly rotational, and looking at the OP-62 you linked that motion should be "ok" with the suggested mounting method.

yep. I used double clamps and flared the tube end slightly. I haven't touched it since new in 900 hrs.
 
With the rotational movement in mind what is the minimum distance from the firewall or bottom of fuselage should the tail pipes be mounted?
I think I probably pushed the limits - about 3/8” below the cross-tunnel brace, but I would do again the same - very happy with it. (Note: the EXP119 places the pipes outside the nose gear, but my install is below.)
 

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