The Ford Barn

46HARLEY · 11-07-2023, 02:25 PM

1946 Deluxe V8 has a intermittent popping from exhaust. Idles perfectly except for an occasional pop. Sticky valve, carburetor, distributor ? Looking for thoughts, similar problems. Thanks

Jack E/NJ · 11-07-2023, 04:46 PM

Try cleaning & gapping plugs to see if popping is reduced.

Ggmac · 11-07-2023, 05:28 PM

Check your distributor vacuum brake . Easy to test , tighten slowly and see if it eliminates the pop . Having no vacuum brake at all can do strange things to the timing and give occasional pops .

46HARLEY · 11-07-2023, 07:48 PM

I will check those, thanks.

flathead4rd · 11-08-2023, 11:05 AM

I had a similar problem and turned out to be a bad spark plug wire.

Tim Ayers · 11-08-2023, 11:22 AM

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Timely thread. My roadster was running NGK B4L plugs. Starting a few weeks back, every time I took the car out, it would run worse. Popping, backfiring especially under acceleration.

I had a hunch it was ignition related, so I checked the plugs. They were gapped correctly, no visible damage, maybe a little sooty from idling with a big cam.

I decided to change them and the car ran as strong as ever before. Something was wrong with the plugs.

I didn't have a way to test the plugs to see what was wrong when firing, but it was a simple fix that cured things up right quick. Hopefully your problem is this simple.

ScubaChief60 · 01-18-2024, 04:41 PM

I had this issue too on my 1935 Flathead V8. Tried everything and found that the fix was that cylinders 7 & 8 were not firing at all. New inner distributor plates and new plug wires... courtesy of Charlie in Buffalo... and it runs like factory now!

Zax40 · 01-20-2024, 12:46 PM

I had a similar issue, when I dropped the replacement 59A in my '40. It ran great at 800RPM and up. But any lower and I got random pops out the exhaust.

Plug wires and cap replacement fixed it. Funny thing is the set that was bad was new. I swapped on the crusty old set off my old flathead as part of troubleshooting and not a single pop out the exhaust since.

11-07-2023, 02:25 PM	#1
46HARLEY Member Join Date: Jul 2021 Location: NY Posts: 54	Intermittent exhaust popping 1946 Deluxe V8 has a intermittent popping from exhaust. Idles perfectly except for an occasional pop. Sticky valve, carburetor, distributor ? Looking for thoughts, similar problems. Thanks

11-07-2023, 04:46 PM	#2
Jack E/NJ Senior Member Join Date: May 2010 Posts: 2,173	Re: Intermittent exhaust popping Try cleaning & gapping plugs to see if popping is reduced.

11-07-2023, 05:28 PM	#3
Ggmac Senior Member Join Date: Jul 2016 Location: Lake worth Florida Posts: 1,104	Re: Intermittent exhaust popping Check your distributor vacuum brake . Easy to test , tighten slowly and see if it eliminates the pop . Having no vacuum brake at all can do strange things to the timing and give occasional pops .

11-07-2023, 07:48 PM	#4
46HARLEY Member Join Date: Jul 2021 Location: NY Posts: 54	Re: Intermittent exhaust popping I will check those, thanks.

11-08-2023, 11:05 AM	#5
flathead4rd Senior Member Join Date: May 2010 Location: Michigan Posts: 505	Re: Intermittent exhaust popping I had a similar problem and turned out to be a bad spark plug wire.

11-08-2023, 11:22 AM	#6
Tim Ayers Senior Member Join Date: May 2010 Location: NJ Posts: 6,182	Re: Intermittent exhaust popping Sponsored Links (Register now to hide all advertisements) Timely thread. My roadster was running NGK B4L plugs. Starting a few weeks back, every time I took the car out, it would run worse. Popping, backfiring especially under acceleration. I had a hunch it was ignition related, so I checked the plugs. They were gapped correctly, no visible damage, maybe a little sooty from idling with a big cam. I decided to change them and the car ran as strong as ever before. Something was wrong with the plugs. I didn't have a way to test the plugs to see what was wrong when firing, but it was a simple fix that cured things up right quick. Hopefully your problem is this simple.

01-18-2024, 04:41 PM	#7
ScubaChief60 Senior Member Join Date: Mar 2023 Location: Summerfield, NC Posts: 153	Re: Intermittent exhaust popping I had this issue too on my 1935 Flathead V8. Tried everything and found that the fix was that cylinders 7 & 8 were not firing at all. New inner distributor plates and new plug wires... courtesy of Charlie in Buffalo... and it runs like factory now!

01-20-2024, 12:46 PM	#8
Zax40 Senior Member Join Date: Feb 2019 Location: Atlanta, GA Posts: 304	Re: Intermittent exhaust popping I had a similar issue, when I dropped the replacement 59A in my '40. It ran great at 800RPM and up. But any lower and I got random pops out the exhaust. Plug wires and cap replacement fixed it. Funny thing is the set that was bad was new. I swapped on the crusty old set off my old flathead as part of troubleshooting and not a single pop out the exhaust since.