The Ford Barn

grf · 10-05-2018, 09:18 AM

1951 ford 8ba with dual 94 carbs
12 volt gen internal ballast coil
stock distributor
idles fine but when you steadily bring up the rpm it starts to back fire and pop thru the carburetor
any ideas

thanks Gerry

tubman · 10-05-2018, 09:55 AM

Quote:

Originally Posted by grf

1951 ford 8ba with dual 94 carbs
12 volt gen internal ballast coil
stock distributor
idles fine but when you steadily bring up the rpm it starts to back fire and pop thru the carburetor
any ideas

thanks Gerry

You just defined the problem. The stock single carb/Loadamatic distributor combination is a specialized pairing. If you change the carburetion, you should change to a distributor with regular mechanical advance, like an old dual point Mallory or a converted GM unit.

JSeery · 10-05-2018, 10:54 AM

Two post on same topic. As tubman posted, sounds like the distributor is not functioning correctly. How is the vacuum line connected?

chap52 · 10-05-2018, 06:03 PM

Here is a great source for distributor and ignition stuff. Chap
http://www.bubbasignition.com/

grf · 10-05-2018, 06:28 PM

the vacuum to distributor is from the carb closest to the firewall
the second carb vacuum is blocked off
if I remove and crimp the vac line from dist and advance or retard there is not much rpm variance

Tinker · 10-05-2018, 08:03 PM

Sponsored Links (Register now to hide all advertisements)

Might be a lean condition. Maybe a stuck valve.

Just an opinion, a single carb and factory "great working" vacuum distributor, works well. As I've been told.

Dual, I'd think about a conversion. Link posted above. Your 12v already, lots of options.

.

flatjack9 · 10-05-2018, 09:22 PM

Quote:

Originally Posted by grf

the vacuum to distributor is from the carb closest to the firewall
the second carb vacuum is blocked off
if I remove and crimp the vac line from dist and advance or retard there is not much rpm variance

That's because there is very little flow through the venturi, so no signal.

Tinker · 10-05-2018, 09:44 PM

Personally I like mechanical with points. No electronics to go bad. No doubt a electronic system will give you great high end performance. Mechanical will get you down the road for decades. Just a thought.

10-05-2018, 09:18 AM	#1
grf Junior Member Join Date: Jan 2017 Location: Lincoln RI Posts: 22	popping back fire 1951 ford 8ba with dual 94 carbs 12 volt gen internal ballast coil stock distributor idles fine but when you steadily bring up the rpm it starts to back fire and pop thru the carburetor any ideas thanks Gerry

10-05-2018, 10:54 AM	#3
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: popping back fire Two post on same topic. As tubman posted, sounds like the distributor is not functioning correctly. How is the vacuum line connected?

10-05-2018, 06:03 PM	#4
chap52 Senior Member Join Date: Jun 2013 Location: Marana Arizona Posts: 1,776	Re: popping back fire Here is a great source for distributor and ignition stuff. Chap http://www.bubbasignition.com/

10-05-2018, 06:28 PM	#5
grf Junior Member Join Date: Jan 2017 Location: Lincoln RI Posts: 22	Re: popping back fire the vacuum to distributor is from the carb closest to the firewall the second carb vacuum is blocked off if I remove and crimp the vac line from dist and advance or retard there is not much rpm variance

10-05-2018, 08:03 PM	#6
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: popping back fire Sponsored Links (Register now to hide all advertisements) Might be a lean condition. Maybe a stuck valve. Just an opinion, a single carb and factory "great working" vacuum distributor, works well. As I've been told. Dual, I'd think about a conversion. Link posted above. Your 12v already, lots of options. . Last edited by Tinker; 10-05-2018 at 08:24 PM.

10-05-2018, 09:44 PM	#8
Tinker Senior Member Join Date: May 2010 Location: MN Posts: 7,053	Re: popping back fire Personally I like mechanical with points. No electronics to go bad. No doubt a electronic system will give you great high end performance. Mechanical will get you down the road for decades. Just a thought.