The Ford Barn

Johnnydidd · 09-01-2016, 01:10 PM

my 56 Merc is running great now only question I have, running at 50 mph or higher when I let upon the gas it will pop back, I love the sound but I don't want to mess something up, it has 18 inch glass packs sounds great.

tinman080 · 09-01-2016, 02:22 PM

could be too lean a mixture....

miker98038 · 09-01-2016, 04:32 PM

"Popping back". Backfire thru the intake, or in the exhaust?

Johnnydidd · 09-01-2016, 05:49 PM

Exhaust

miker98038 · 09-01-2016, 06:45 PM

That was more common on carburetor cars, especially down a long hill on compression. I never knew what caused it exactly, something in the way the fuel gets suck thru no doubt. I've got an OT car were I can turn the fuel shut off on the EFI "off", and it'll pop on the exhaust on a long downgrade. The short mufflers are probably making it more noticeable. So it's not uncommon, and someone here will know why it happens. Then we both will.

dmsfrr · 09-01-2016, 06:48 PM

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When you let off the gas pedal some excess unburned fuel mixture goes into the exhaust. The mixture ignites in the exhaust pipes instead of in the engine. As long as the carb/engine isn't running too rich it should be fine.

https://www.reddit.com/r/cars/commen...haust_popping/

https://www.google.com/search?q=popp...utf-8&oe=utf-8

Johnnydidd · 09-01-2016, 08:34 PM

Thanks guys, love the sound

50fordcoupeman · 09-01-2016, 08:41 PM

Yes on dmsfrr's response. Unburned fuel in exhaust is igniting. Blew grandpa's muffler off his 40 Ford farm truck once. We both got a chuckle as we fixed it. He told me not to leave the key off so long next time............how did he know?? Wonderful ol grandpa!!!!

dmsfrr · 09-01-2016, 09:03 PM

Quote:

Originally Posted by Johnnydidd

..... love the sound

Times 2

If the stock mufflers on this '55 weren't like new I'd change them to something with a better sound.

09-01-2016, 01:10 PM	#1
Johnnydidd Senior Member Join Date: Mar 2011 Location: Overland Park, Ks Posts: 559	popping back my 56 Merc is running great now only question I have, running at 50 mph or higher when I let upon the gas it will pop back, I love the sound but I don't want to mess something up, it has 18 inch glass packs sounds great.

09-01-2016, 02:22 PM	#2
tinman080 Senior Member Join Date: Oct 2015 Location: Forest, Virginia Posts: 250	Re: popping back could be too lean a mixture.... __________________ Just Passin' Thru.....Slowly!

09-01-2016, 04:32 PM	#3
miker98038 Senior Member Join Date: Mar 2013 Location: Kent, WA. Tucson, AZ Posts: 1,405	Re: popping back "Popping back". Backfire thru the intake, or in the exhaust?

09-01-2016, 05:49 PM	#4
Johnnydidd Senior Member Join Date: Mar 2011 Location: Overland Park, Ks Posts: 559	Re: popping back Exhaust

09-01-2016, 06:45 PM	#5
miker98038 Senior Member Join Date: Mar 2013 Location: Kent, WA. Tucson, AZ Posts: 1,405	Re: popping back That was more common on carburetor cars, especially down a long hill on compression. I never knew what caused it exactly, something in the way the fuel gets suck thru no doubt. I've got an OT car were I can turn the fuel shut off on the EFI "off", and it'll pop on the exhaust on a long downgrade. The short mufflers are probably making it more noticeable. So it's not uncommon, and someone here will know why it happens. Then we both will.

09-01-2016, 06:48 PM	#6
dmsfrr Senior Member Join Date: Aug 2012 Location: Abq, NM Posts: 3,610	Re: popping back Sponsored Links (Register now to hide all advertisements) When you let off the gas pedal some excess unburned fuel mixture goes into the exhaust. The mixture ignites in the exhaust pipes instead of in the engine. As long as the carb/engine isn't running too rich it should be fine. https://www.reddit.com/r/cars/commen...haust_popping/ https://www.google.com/search?q=popp...utf-8&oe=utf-8

09-01-2016, 08:34 PM	#7
Johnnydidd Senior Member Join Date: Mar 2011 Location: Overland Park, Ks Posts: 559	Re: popping back Thanks guys, love the sound

09-01-2016, 08:41 PM	#8
50fordcoupeman Senior Member Join Date: Mar 2016 Location: LaGrande Oregon Posts: 866	Re: popping back Yes on dmsfrr's response. Unburned fuel in exhaust is igniting. Blew grandpa's muffler off his 40 Ford farm truck once. We both got a chuckle as we fixed it. He told me not to leave the key off so long next time............how did he know?? Wonderful ol grandpa!!!!