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Muffler / Oil Drain Fitting - Clearance
- Thread starter Piper J3
- Start date
I?m doing the Annual Condition Inspection on my 12 and notice the 90? fitting on the bottom of the crankcase for the oil return line is almost touching the muffler. See photo... I don?t recall seeing this on the previous inspection. Any thoughts?
It looks to me like that hose is not routed per the KAI.
The fitting should be pointed almost directly aft with the hose routing to the oil tank via a path upward behind the engine.
The clearance is close for the normal routing, but not that close.
Also make sure all of your springs are in good shape and that the muffler is properly seated on the pipes.
Harvey rv12
Well Known Member
Jim;
I had the exact same problem on my -12 that I purchased. I was certain the oil line fitting was going to rub thru after chafing on the muffler, and drain all my oil out during flight. After much research, I discovered that a banjo type fitting should be used there. It provides much more clearance between the line and the muffler body. Don't have any pics, but just look in the rotax info for the banjo type fitting in the bottom of the crankcase. My local A&P installed it. I sleep better now.
Tom O.
I had the exact same problem on my -12 that I purchased. I was certain the oil line fitting was going to rub thru after chafing on the muffler, and drain all my oil out during flight. After much research, I discovered that a banjo type fitting should be used there. It provides much more clearance between the line and the muffler body. Don't have any pics, but just look in the rotax info for the banjo type fitting in the bottom of the crankcase. My local A&P installed it. I sleep better now.
Tom O.
If the 90 degree hose is installed correctly it has worked just fine on 100's of RV-12's.
If the banjo fitting is used the hose has to be routed to the side, and the hose path ends up being less than direct to the oil tank.
If the banjo fitting is used the hose has to be routed to the side, and the hose path ends up being less than direct to the oil tank.
Piper J3
Well Known Member
Thank you Scott for quick reply. I will check engine install drawings for drain hose routing and see if I can turn fitting more aft and run the hose up the backside of the engine.
I may also remove the muffler and make a small "smile" dent to increase clearance for the 90? fitting. This looks like a good option...
I may also remove the muffler and make a small "smile" dent to increase clearance for the 90? fitting. This looks like a good option...
Harvey rv12
Well Known Member
fitting radius
I believe some of the Aeroquip fittings for the crankcase oil return line have a larger bend radius, perhaps a different part number. I think the larger radius is the cause of the interference.
Tom O.
I believe some of the Aeroquip fittings for the crankcase oil return line have a larger bend radius, perhaps a different part number. I think the larger radius is the cause of the interference.
Tom O.
No, that is a short radius ell
Here is a comparison of an installed short radius ell and a standard radius ell held up next to it. The one shown in Piper J3's picture is the correct short radius. I don't think it would be even possible to install a standard radius ell in this location.
I have looked at several 12's and there is not much clearance on any of them.
Here is a comparison of an installed short radius ell and a standard radius ell held up next to it. The one shown in Piper J3's picture is the correct short radius. I don't think it would be even possible to install a standard radius ell in this location.
I have looked at several 12's and there is not much clearance on any of them.
Piper J3
Well Known Member
A good day...
I dropped the muffler and then re-routed the oil return line so the fitting faces aft and the line comes around the back of the engine. I now have good clearance between the 90 degree fitting and muffler. See pic. Muffler looks a little grungy - phone camera doesn't do it justice.
I want to thank everyone for their help. I bought this airplane from the original builder and I guess I'm still sorting out some issues...
I dropped the muffler and then re-routed the oil return line so the fitting faces aft and the line comes around the back of the engine. I now have good clearance between the 90 degree fitting and muffler. See pic. Muffler looks a little grungy - phone camera doesn't do it justice.
I want to thank everyone for their help. I bought this airplane from the original builder and I guess I'm still sorting out some issues...
Chrysopelea
Active Member
The muffler on my 12 is also a little grungy. I think it just goes with being what it is.
Maybe painting it, or having it ceramic coated would clean things up, but on mine, over time, oil, coolant, drool, all has dripped onto the muffler and it gets baked on and doesn't come off.
Anyone else keep breaking safety wires and springs too? I just had to replace the safety wire on 3 of my springs.
Maybe painting it, or having it ceramic coated would clean things up, but on mine, over time, oil, coolant, drool, all has dripped onto the muffler and it gets baked on and doesn't come off.
Anyone else keep breaking safety wires and springs too? I just had to replace the safety wire on 3 of my springs.
If you are breaking safety wire on the muffler, it is being installed incorrectly.
The primary purpose of the safety wire is to prevent a broken spring from exiting the airplane (particularly important in a pusher configuration).
The wire should be installed loose enough to allow system expansion/contraction (that is why springs are used). If the wire is breaking, it is likely being installed way too tight.
Yes, I replaced the original springs with the Spruce springs at two years and 155 hours. The originals were getting very rusty and showed some wear, despite using the recommended RTV to dampen vibrations. The new springs now have about the same hours on them as the originals had and they are holding up pretty well.
As to safety wiring the springs, I guess that is personal choice if you like the belt AND suspenders theory. Personally I don't see the need for it in the RV-12 installation.
Chrysopelea
Active Member
On my safety wired springs, I've replaced 2 springs so far, and fixed 4 safety wires, all were RTV'd (before and after), save for the last one because I didn't have any RTV handy when putting the cowling back on.
I double wrapped my safety wires, once outside the spring, and once through the spring, and pulled them tight, but not guitar string tight. Tight enough so if the spring were to break, things wouldn't move very much that's for sure.,
I recently adjusted my prop pitch (blades were over 2.5 degrees off from each other) and it SERIOUSLY smoothed things out, and I think this may have been the reason my springs and safety wires were breaking at what seems like a fast rate.
I double wrapped my safety wires, once outside the spring, and once through the spring, and pulled them tight, but not guitar string tight. Tight enough so if the spring were to break, things wouldn't move very much that's for sure.,
I recently adjusted my prop pitch (blades were over 2.5 degrees off from each other) and it SERIOUSLY smoothed things out, and I think this may have been the reason my springs and safety wires were breaking at what seems like a fast rate.
RFSchaller
Well Known Member
500 hours and the springs look great. Only one VR failure, two EGT failures, only one tire replaced and now finally a squirrelly oil pressure sensor. By the measure of this forum my 12 is living a charmed life!
