Exhaust smell in cabin

[Olle1975]

Hello together!

First, I'm from germany, sry about my english. I have a kitfox III with Rotax 582 greyhead with aluminium wing and headertanks.
I haven't got any fuel or oil smell in my cabin, not in hangar and not during fly. But I have a little exhaust smell during fly and after fly, my clothes smells like exhaust. I checked my exhaust system (original Rotax muffler) and the way out of the cowling, the end of the system is longer than the original, I modified it with flexibel alu tube. I checked the firewall, I seal up my doors with rubber and I seal up the holes in bottom.
Is it possible, that the Prop washer pulls the exhaust by an another way into the cockpit, may be throught the turtle-deck? Has anybody further ideas of ways the exhaust could get in?

Thanks

Olaf

[Av8r3400]

I would bet the "ball joint" in the exhaust is leaking. The joint between the manifold and the expansion chamber, held together with springs.

These can need not only cleaning but lapping together to make a perfect fit.

[Olle1975]

Hello!

I checked the "ball joint", I dismantle these connections, cleaned with steelbrush, greased with copper-paste and connected with good springs.
I can't believe, that there is a leak.........hope so ;-)

Olaf

[Eric]

`Maybe via the bottom of the plane via the openings for the bungees?

Eric

[Olle1975]

Thanks, but I use a grove gear ;-)

Olaf

[Av8r3400]

Hello!

I checked the "ball joint", I dismantle these connections, cleaned with steelbrush, greased with copper-paste and connected with good springs.
I can't believe, that there is a leak.........hope so ;-)

Olaf

I've heard of several people who needed to lap this joint to make it fit. That means to put a polishing compound in the joint and rub and twist the two parts together until their fit is perfect.

Maybe your exhaust pipe is too long, allowing exhaust to swirl up the side of the plane into the door?

[Dave S]

Olaf,

Just a couple ideas......1) Is this an issue that recently appeared; or, has it been there all the time? 2) Does this occur all the time or only with a certain configuration - such as only during the winter with the cabin ventilation different than in the summer? During certain maneuvers? 3) Did the issue appear after any changes anywhere to the airplane? Firewall lower lip area? Radiator placement?.......

I have found that the air flow inside our series 7 changes depending on how the vents are used and even with maneuvering (slips, etc) ......with the doors and cabin closed up as tightly as a person can make them, air can be drawn into the fuselage through the tail access area and back up to the cabin. If air comes into the plane through any point like the tail access covers, whatever is in that air will obviously come with. The inside of the fuselage, depending on whatever is going on may be under slight pressure or slight vacuum depending on how the airflow around the plane works with whatever openings or protrusions exist.

There are differences among our planes due to model and due to specific construction of any individual plane.

This can be a difficult deal to figure out because we can't directly see air flow...

Among other things that people have offered, Might be worth considering any unsealed areas anywhere in the fuselage including anywhere behind the cockpit.

Sincerely,

Dave S
KF 7 Trigear
912ULS Warp Drive
Minnesnowta,MN

[Av8r3400]

Do you know which compound I could use because of temperature?

The compound is used when the pipes are cold and disassembled. You polish the parts against one another then clean out all of the compound before reassembly and installation into the airplane.

[Olle1975]

1) Is this an issue that recently appeared; or, has it been there all the time? 2) Does this occur all the time or only with a certain configuration - such as only during the winter with the cabin ventilation different than in the summer?

I think it's during start mainly and during flight barely, but It's possible that I feel habit after a time. Smell in all seasons.

Did the issue appear after any changes anywhere to the airplane?

No changes, it's smells by first time.

Firewall lower lip area?

Checked

Radiator placement?.......

Footwell, bypass Watercooler

You polish the parts against one another then clean out all of the compound before reassembly and installation into the airplane.

OK, I thought it's for sealing up the "ball joint" a compound which works during flight and have to work during high temperature like a exhaust bandage.

Olaf

[Av8r_Sed]

I lapped my ball joints, and lapped... and lapped... and lapped some more. I started with course valve lapping compound and moved on to fine. They're good now, but I still have a small leak at the first ball joint by the exhaust manifold. I don't get any noticible exhaust smell in the cockpit with the stock exhaust system and bungee gear.

Link: http://www.ebay.com/itm/2219-VALVE-G...p2054897.l4276