The Ford Barn - View Single Post - 31 Roadster "chuffs" when shifting after it is warmed up

Bill G · 10-11-2017, 10:51 PM

My '29 Tudor has a small-ish backfire after fully warming up and when decelerating or in the process of shifting down. Maybe your "chuff" is the same thing I am experiencing, although mine is pretty noticeable because I think my muffler is also shot.

After tons of reading and searching this forum and others, I am convinced I have a leak perhaps in the junction where the exhaust pipe to the muffler clamps to the exhaust manifold and a lean mixture.

I can lessen the effect, but not eliminate it entirely by opening the GAV and making the mixture a little richer, so I am convinced of the "after-burner" effect going on in the muffler. Yours may be the same, but with a better muffler than I have.

Try opening the GAV. Normal operation is less than a turn counter-closkwise, but try it with it open more.

10-11-2017, 10:51 PM	#4
Bill G Senior Member Join Date: Jun 2017 Location: Walla Walla, WA Posts: 1,045	Re: 31 Roadster "chuffs" when shifting after it is warmed up My '29 Tudor has a small-ish backfire after fully warming up and when decelerating or in the process of shifting down. Maybe your "chuff" is the same thing I am experiencing, although mine is pretty noticeable because I think my muffler is also shot. After tons of reading and searching this forum and others, I am convinced I have a leak perhaps in the junction where the exhaust pipe to the muffler clamps to the exhaust manifold and a lean mixture. I can lessen the effect, but not eliminate it entirely by opening the GAV and making the mixture a little richer, so I am convinced of the "after-burner" effect going on in the muffler. Yours may be the same, but with a better muffler than I have. Try opening the GAV. Normal operation is less than a turn counter-closkwise, but try it with it open more.