[647jc]

I have a pretty basic 9A with an O-320 Lyc. and standard Vetterman crossover exhaust system hung via the Van/Vetterman exhaust hanging system. After about 70 hours on the airplane I noticed the exhaust pipe(s) are rubbing against the engine mount and has rubbed off some of the powder coating. I need to correct this before it gets any worse. The problem appears to be caused by the exhaust pipes ability to swing sideways ?? or more. The hanging system does not lock the pipes in place and you can grab the end of the pipe(s) and pull them from side to side where they will hit the engine mount. You can center them so they clear the engine mount and clear the sides of the bottom cowl exhaust tunnel but just about any engine movement (startup, etc.) can shift the pipes to one side or the other where they will start to rub the engine mount. There just isn?t much clearance to play with in that area since you need to keep clear of both the cowl tunnel sides and the engine mount. So, I suspect I?m not the only person to encounter this problem and was wondering how others may have addressed the issue.

 

[petehowell]

Protection

Hi Joe,

Same issue here - I glued some thick walled AL tubing over the engine mount where it rubs. Has held up fine for 500+ hours. Will need to replace it at about 1000 based on wear. Some heavy rubber fuel line would do about the same, I suspect.

 

[carguy614]

9A exhaust

I too have had the same issue. I helped mine by installing heavier hose stock on the hangers. Instead of the regular old fuel line, I used reinforced hose, much like power steering return line hose which is much more rigid. This seems to have stiffened up the whole installation enough to keep it all centered up.
See your friendly NAPA dealer for the hose stock.

Hope this helps...Chris

 

[terrykohler]

Same Problem

Initially I tried clamping rubber tubing around the engine mount. Bad idea. Didn't solve the contact problem and was still creating excess noise (though not as much). Solved by repositioning the pipes and hangers. Note: The AI that used to handle my 210 told me to allow 1/2 inch in every direction - engine moves a lot, especially during startup and shutdown. I'm now getting a little rubbing on the lower cowl outlet, but not enough to warrant further adjustment. No problems past 200 hours.
Terry, CFI
RV-9A N323tp

 

[N941WR]

... I'm now getting a little rubbing on the lower cowl outlet, but not enough to warrant further adjustment. No problems past 200 hours.
Terry, CFI
RV-9A N323tp

Try taking some sandpaper and roughing up the SS tubes so the rubber tubes have something to hold on to and won't move.

Terry, I would adjust your exhaust so it doesn't make contact with the cowling. Eventually the cowling will cut through the exhaust tube, which could make for a very bad day.

Remember, it is always the softer material that cuts through the harder material. The reason is that when two items first start rubbing together, the hard material pushes microscopic particles into the soft material. Then the soft material starts to work like a saw and cuts into the harder material. That's why rubber seals cut through steel.

 

[rv9av8tr]

Exh pipe movement

Did you install the cross support between the pipes?
http://www.mykitlog.com/users/display_log.php?user=n539rv&project=161&category=0&log=85851&row=6

Once I put the cross-support rods in place and snugged up the balljoints per plans, the pipes seem pretty fixed as a single unit. The other thing to keep in mind is that the engine rotates significantly due to torque. The pipes are the furtherest away from engine centerline, so you'll see the most rotation there.

 

[Jef Vervoort]

exhaust system hanging

Mike,

I see that you positioned the pipe support brackets before/above the last bend in the exhaust, while L. Vetterman suggests to place them below the last bent.
Did you do that because otherwise there was insufficient room for the cross support rod, and it would probably rub the engine mount tubing?

How is it behaving in flight?

Greetings,
Jef Vervoort, Belgium, 91031.

 

[flyboy1963]

exhaust contact

same here Joe, at about 100 hrs, things have moved enough to allow contact .
To be fair, the original builder had a very rigid mount, which may have lasted forever, but I wanted a bit more flex, so I just used longer bolts in the stock hangars, and put fuel line hose as a big tubular washer to allow some flex.
This ofcourse, ended up being enough flex to allow occasional contact with the engine mount.
I like the idea of another hanging point, but I guess I'd prefer not to remove the ball joint function from the system. Hmm, not a lot of choices down there.

 

[PensacolaPilot]

exhaust pipe rubbing

I've flown my airplane, a RV 6A, about 250 hrs when I had to weld a small crack on one of the exhausts near the flange. (Vetterman exhaust system) After re-install I noticed the exhaust pipe rubs against the cowling where it narrows anddrops down for the air scoop. I've got about a 1/2 inch clearance between the pipe and the fiberglass (protected with heat shield foil) when the engine is not running/producing torque. I'm thinking about having the exhaust pipes bent at the offending place. Thoughts? Drawbacks? what am I missing?