Help Please, Engine Smell?

[Bill Greenwood]

I flew my B 36 TC Bonanza about 45min , and all was normal, smooth day, vmc and normal approach and landing. In fact the landing was one of my best, But then on taxi to parking I noticed a smell,sems like burning. All gauges look normal, oil temp after shutdown about 80C just as usual. Opeing cowlings, engine seems normal, except a acrid burnig smell on the right hand side. Cant see anything wrong, except find a bird feather and a few twigs of grass, nothing seems to be burning.
Let it sit for couple of hours and checked oil, pretty full at about 10 1/2 qts of 12, and oil smells and looks normal, even has a bit of a green color not black.
Did a start and brief run up, all temps and pressures normal. Mag and prop check normal. Prop seems free to turn post flgith.
Cant see any obvious hot spot or oil leak even with lower side cowling off, very minor oil residue under engine ,proabbaly from a past leak, no signs of anything new. Nothing, alternator, etc seems unduly hot to touch. Battery box is hard to open but looks normal inside from what I can see, though does seem to have the same acrid burn smell as the engine.
The smell seems mostly on the right side of engine, not much in cockpit, and less on left side.

I know it is very hard to make any determination from only this info, but thats all I have, engine and gauges seem normal, except for the smell. I am not sure where to go from here, and no mech on duty today. Any Ouigi board operators out there, all are welcome.

[wacoc8]

Check the exhaust for a leak, especially near the cylinder head. Sometimes when you are getting blow-by on an exhaust port you will get a different type smell.

Fly safe,

Dave

[1600vw]

My cylinders were honed on an A-65 I owned. When I did my runup I got this same smell you describe. If I would have not known that the cylinders were just honed I would have thought the engine took a crap or something. I would say, and no expert here by any means, but I would say you are getting blow-by and you are smelling it. This blow-by smells awful. A ring could have taken a crap or broken. I would do a leak down test on all cylinders and see if something has changed from the last leak down test. Again no expert but what I would do.

Good luck Bill.

Tony

[Bill Greenwood]

Tony, thanks for the guess, but I dont think it is the case. Nothing new like honing on my clyinders. I would think blow by would show in the oil, either a smell or discoloration and there is none of that, and all cylinders look normal on my 6 part engine monitor for cht which are close and in limits under 400* more like 350* in cruise. Oil consumption is mimimal. Dont see why a ring would have a problem just taxing in.
I am thinking this is an accesory item, I have backup vac and gen systems, but cant find any evidence of any problem or heating on them. Could be just a bird or small animal was caught in the engine and fell out, leaving the smell, but cant see any evidence of it and that is almost too good to hope for. Somewhere down in the maze of wires there may be two that are touching since this is a very acrid smell, seems a bit like electrics to me. The a & p is going to take a look in the am.
Thanks

PS my Beech expert says to check wires out of alternator for chafing which I did and no sign of a problem and next to run my hand over exhaust pipe to check for leaks, which I wll do next.

[skyfixer8]

Bill, Wacoc8 was suggesting look at exhaust gaskets. Blo proof gaskets like to blow out sometimes.

Bill L

[Bill Greenwood]

Bill L. and Dave, thanks, I just spoke by phone to a top Beech shop and they said there is an exhaust junction low on the right side and to check if the gasket might be leaking exhaust blowing on a wire. I will try to look for that.
I appreciate the suggestions.

[Bill Greenwood]

I just had a friend run the engine while I opened the right side cowling. Sure enough in a moment, the same smell, and smoke came out of the vent on top of the alternator. Why is not yet known, did the alt just go bad or did something cause it to overheat?
Strangely nothing indicated on load meter, and could not generate a load with turning on some switches. . Exhaust, as for as we can see seems ok, is hard to see down low under things. The smell is bad!!!!

[Bill Greenwood]

Alternator is not working, but ran it for a few moments with alt off and doesnt seem to be burning, no smoke or smell so Ive ordered an OH alt. We'll see
Thanks

[Bill Greenwood]

After installing an oh alternator, and doing a run up, it is normal. No acrid smell,or smoke, or leaks and it is charging 28.5 volts is should.And the loadmeter which didnt show an load at all before, now was normal. It must run through the alternator. The bearing in the alterantor was good and turned freely, so we dont know exactly what caused it to fail. Electric burning smoke is very acrid and doesn't small like exhuast or even an oil leak.
Thanks for all the suggestions.

[pacerpilot]

I usually blame the dog.