The International Cessna^® 170 Association

Gentlemen,

I recently noticed that after a flight, the exhaust stains on the left side of the cowling look different than on the right.
The right side show very little greyish stains, the left more noticable brownish oily stains. Why just one side?
I also think the oil consumtion has increased a little bit. (About .25 qt/h). Any ideas? Not sure but full static power at 4000 AMSL is 2200 RPM, engine is a Cont O-300-C.
Thanks.

This is due entirely to which side of the Atlantic Ocean one is on. You've heard of the Earth's coriollis effect? Well, that refers to the direction that water goes down the toillet, and only applies to northern hemisphere versus southern hemisphere.

The exhaust stains on the belly are due to the whirlwind effect differences which occur (mostly) due to airplanes mfr'd on the east side of the Atlantic...versus those mfr'd on the west side of the Atlantic.

(More serious answer: American airplanes have clockwise prop rotation which places greater impingement of exhaust gases on the left side of your cowl due to prop rotation creating a whirlwind that his clockwise. A counter-clockwise prop ...such as is prevalent on British airplanes.... would be opposite, placing exhaust stains on the right side cowl... if the engine is exhausted downwards.)

The stains are not on the belly but right behind the exhaust tubes.
Could it be that one of the left cylinders is burning more oil than the right side ones?

gahorn wrote:This is due entirely to which side of the Atlantic Ocean one is on. You've heard of the Earth's coriollis effect? Well, that refers to the direction that water goes down the toillet, and only applies to northern hemisphere versus southern hemisphere.

The exhaust stains on the belly are due to the whirlwind effect differences which occur (mostly) due to airplanes mfr'd on the east side of the Atlantic...versus those mfr'd on the west side of the Atlantic.

(More serious answer: American airplanes have clockwise prop rotation which places greater impingement of exhaust gases on the left side of your cowl due to prop rotation creating a whirlwind that his clockwise. A counter-clockwise prop ...such as is prevalent on British airplanes.... would be opposite, placing ehaust stains on the right side cowl... if the engine is exhausted downwards.)

This reads like total and complete prop wash.

Bill

Gman wrote:The stains are not on the belly but right behind the exhaust tubes.
Could it be that one of the left cylinders is burning more oil than the right side ones?

When I said "belly"... I was referring to the "belly" of the cowling. Yes, of course it's on the cowl, just behind the exhaust tailpipe as you said.. And also a bit probably on the lower belly near the left strut, if you run it long enough between washings.

Long shot. My primer is only connected to my left intake manifold. If the primer leaks thru due to the primer not shutting off then the left exhaust will be darker than the right side exhaust pipe. It should be dry soot, and not wet from oil
Dave

George is right about the motion of the prop......also the stains are more prevalent when using mogas as opposed to 100 LL with TCP or the other(new) additive which escapes my mind right now.....

davevramp wrote:Long shot. My primer is only connected to my left intake manifold. If the primer leaks thru due to the primer not shutting off then the left exhaust will be darker than the right side exhaust pipe. It should be dry soot, and not wet from oil
Dave

Interesting, I also only have the primer on the left side, will check for leaks.
Thanks