Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 01-24-2021, 04:09 PM   #1
srg
Junior Member
 
Join Date: Mar 2019
Posts: 10
Default Runs great until it heats up

1937 with a 59AB engine, offenhauser manifold, sharp heads, denton headers, two stomberg 97 carbs. Has a mallory electronic distributor with the corresponding coil. It ran great before. Now it runs great until it gets hot and starts to miss and evolves into stalling with the foot off the gas. It STARTS immediately every time after it stalls, but resumes running with mega missing, until it stalls again. Any ideas? Ignition? But it starts every time after stalling, but misses bad. It recovers while missing if I pump the gas pedal like crazy but drops back into mega missing. Carbs? It starts and runs great until I am at temperature for a while (160-180). Coil? Resistor?
There is a strange sound coming out of the engine when this condition presents, like one side of the engine isn't firing the fuel, kind of a gurgling.

Brain stormers needed. Thanks guys.
srg is offline   Reply With Quote
Old 01-24-2021, 04:18 PM   #2
deuce lover
Senior Member
 
deuce lover's Avatar
 
Join Date: May 2010
Location: Southern France
Posts: 5,279
Default Re: Runs great until it heats up

Try another coil. In a '36 coupe I had a few yrs ago similar to yours (Sharp Heads,Mallory ign 2 97's)except for a Potvin super cam .When coil got hot ,car stalled and died.Let it cool down and it would start right up and then 3 miles later died.I replaced the coil and that cured it.
deuce lover is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 01-24-2021, 04:44 PM   #3
Ford Freak
Senior Member
 
Join Date: Feb 2013
Location: Pittsford NY. USA
Posts: 1,094
Default Re: Runs great until it heats up

Coil .......
__________________
1952 Ford F1
1965 Ford Falcon Sprint
2007 Ford Mustang GT
Ford Freak is offline   Reply With Quote
Old 01-24-2021, 04:45 PM   #4
50fordcoupeman
Senior Member
 
50fordcoupeman's Avatar
 
Join Date: Mar 2016
Location: LaGrande Oregon
Posts: 865
Default Re: Runs great until it heats up

Mine was also coil................
50fordcoupeman is offline   Reply With Quote
Old 01-24-2021, 06:31 PM   #5
tubman
Senior Member
 
tubman's Avatar
 
Join Date: Dec 2013
Location: Minnesota, Florida Keys
Posts: 10,260
Default Re: Runs great until it heats up

That's the most likely suspect, but it might also be the condenser. They can fail when hot as well.
tubman is offline   Reply With Quote
Old 01-24-2021, 06:46 PM   #6
flatjack9
Senior Member
 
flatjack9's Avatar
 
Join Date: May 2010
Location: Oshkosh, Wi
Posts: 4,516
Default Re: Runs great until it heats up

Sponsored Links (Register now to hide all advertisements)
Check the primary resistance on the coil. Mallory is notorious for providing the wrong coil. With a 12v system, you'll want a total of about 3.5 ohms resistance.
flatjack9 is offline   Reply With Quote
Old 01-25-2021, 12:06 AM   #7
JayChicago
Senior Member
 
JayChicago's Avatar
 
Join Date: Jan 2019
Location: Chicago
Posts: 711
Default Re: Runs great until it heats up

But guys, what about this symptom from the original post:
"It recovers while missing if I pump the gas pedal like crazy"
JayChicago is offline   Reply With Quote
Old 01-25-2021, 12:19 AM   #8
Tinker
Senior Member
 
Tinker's Avatar
 
Join Date: May 2010
Location: MN
Posts: 7,053
Default Re: Runs great until it heats up

Agree with Jay. Maybe fuel related... Could be anything really. But maybe the ignition is recovering just enough to run poorly.


If it runs well every time its started from a normal cold state, and it only acts up under warm (160-180) conditions. I don't think its a vapor issue.


Clean plugs, run it till it fails. Check plugs.


***Normally I would say when its stalling to pull the choke slowly and if it runs better, then it's a lean condition. But you have a dual setup. If the primary has a choke that you can run manually. try that. Just a thought.

Last edited by Tinker; 01-25-2021 at 12:45 AM.
Tinker is offline   Reply With Quote
Old 01-25-2021, 12:47 AM   #9
srg
Junior Member
 
Join Date: Mar 2019
Posts: 10
Default Re: Runs great until it heats up

Thanks Deuce. Mine starts right back up, even while hot, but resumes missing like crazy. Start it up while cold, no problem.
Jay: When I mentioned "it recovers" when pumping the gas, it would be more accurate to say I can coax it down the road a bit doing that, but the missing with resulting noises from the engine catch up with me and it stops running. I roll to a stop, push the start button, it starts right up but misses badly, then stops again. I've coaxed it back to my garage by pumping the pedal furiously. I appreciate all you're guys help. I'll check that coil. I put my hand on the coil when I got it back yesterday and that sucker was hot. It's mounted right next to the manifold above the left head in the front of the engine.
srg is offline   Reply With Quote
Old 01-25-2021, 12:52 AM   #10
Tinker
Senior Member
 
Tinker's Avatar
 
Join Date: May 2010
Location: MN
Posts: 7,053
Default Re: Runs great until it heats up

Condenser or coil... But I'd mention valves sticking. My truck that's rebuilt does this every spring after sitting. It idles just fine till I put load on it. It bucks underload. I do a mmo carb dump every spring and it clears it up. I know the idea of the mmo thing is a bit lame. But it works.
Tinker is offline   Reply With Quote
Old 01-25-2021, 01:08 AM   #11
koates
Senior Member
 
Join Date: May 2010
Location: Melbourne Australia.
Posts: 2,076
Default Re: Runs great until it heats up

Vacuum leak on the intake manifold and its running lean (too much air) thats why it picks up when you pump the accelerator pump and it gets more fuel to even up the mixture. Connect a vacuum gauge to the intake manifold for a test. Regards Kevin.
koates is offline   Reply With Quote
Old 01-25-2021, 02:49 AM   #12
Tinker
Senior Member
 
Tinker's Avatar
 
Join Date: May 2010
Location: MN
Posts: 7,053
Default Re: Runs great until it heats up

Quote:
Originally Posted by koates View Post
Vacuum leak on the intake manifold and its running lean (too much air) thats why it picks up when you pump the accelerator pump and it gets more fuel to even up the mixture. Connect a vacuum gauge to the intake manifold for a test. Regards Kevin.

adding a little choke when it's running underload will also decrease air flow.
Tinker is offline   Reply With Quote
Old 01-25-2021, 03:04 AM   #13
deuce lover
Senior Member
 
deuce lover's Avatar
 
Join Date: May 2010
Location: Southern France
Posts: 5,279
Default Re: Runs great until it heats up

As Koates says plus a vacuum leak will cause it to idle rough.
deuce lover is offline   Reply With Quote
Old 01-25-2021, 06:07 PM   #14
srg
Junior Member
 
Join Date: Mar 2019
Posts: 10
Default Re: Runs great until it heats up

Tinker: What's an MMO carb dump?
srg is offline   Reply With Quote
Old 01-26-2021, 02:02 AM   #15
deuce lover
Senior Member
 
deuce lover's Avatar
 
Join Date: May 2010
Location: Southern France
Posts: 5,279
Default Re: Runs great until it heats up

I think its Mystery Marvel Oil and maybe he pours it in the air horn.Never heard of that remedy.Sounds like your setup is pretty fresh so the shouldn't be necessary.
deuce lover is offline   Reply With Quote
Old 01-26-2021, 03:10 AM   #16
aussie merc
Senior Member
 
aussie merc's Avatar
 
Join Date: Sep 2016
Location: sydney australia
Posts: 1,025
Default Re: Runs great until it heats up

start with coil then condenser and also check that the dissy advance is not jammed or worse broken springs
aussie merc is offline   Reply With Quote
Old 01-26-2021, 07:57 PM   #17
AnthonyG
Senior Member
 
AnthonyG's Avatar
 
Join Date: May 2013
Location: Pa.
Posts: 2,161
Default Re: Runs great until it heats up

Many posts w same over the years, mot of the time Coil or condenser bad. Didn’t quite understand when it occurs? If in neutral does it happen or just under load?
__________________
Nomad
AnthonyG is offline   Reply With Quote
Old 01-27-2021, 12:12 AM   #18
Tinker
Senior Member
 
Tinker's Avatar
 
Join Date: May 2010
Location: MN
Posts: 7,053
Default Re: Runs great until it heats up

Quote:
Originally Posted by deuce lover View Post
I think its Mystery Marvel Oil and maybe he pours it in the air horn.Never heard of that remedy.Sounds like your setup is pretty fresh so the shouldn't be necessary.

Lead was used for L head motor upper cylinder lucubration. Guess it's a thing, as they sell lead additive now. Which I would never buy.

On a new rebuilt motor like mine the tolerances are very tight and every amount of lubrication in the valves/guides help on a L head motor.

Just pour mmo down the carb at idle till it smokes out. Then drive the crap out of it. Rinse, repeat.

Maybe I'm wrong, but sticky valves do happen. As I mentioned it could be a lot of things. Like the coil and condenser.... maybe the Mallory is being weird? Don't know, I run points.

Last edited by Tinker; 01-27-2021 at 01:33 AM.
Tinker is offline   Reply With Quote
Old 01-27-2021, 08:30 PM   #19
srg
Junior Member
 
Join Date: Mar 2019
Posts: 10
Default Re: Runs great until it heats up

Anthony: Happens under load and idling.
srg is offline   Reply With Quote
Old 01-27-2021, 08:38 PM   #20
srg
Junior Member
 
Join Date: Mar 2019
Posts: 10
Default Re: Runs great until it heats up

Thank you guys. This is my attack plan: 1. Take all connectors off of coil and resister and clean them. Test. 2. Check intake manifold. Test 3. get new resistor. Test. 4. Get new coil. Test. The resistor (OEM) under the dash is disconnected. I'll carefully inspect spark plug wires and coil resistor wiring. Here's something that happened I haven't thought about; the dudes at the body shop welded on the car without disconnecting the battery. I believe that's a very bad idea.
srg is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 09:13 PM.