Topic: Runs great until it gets hot


srg    -- 01-24-2021 @ 1:14 PM
  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.
Need some brainstorming here from the trust. Thanks guys.


pauls39coupe    -- 01-24-2021 @ 5:37 PM
  Wild guess, but do you have a stuck thermostat on one side? Over heats gurgles? If your temperature sender is only on one side reading 180 while the other side boils?
Pumping the throttle may cool the mixture for a moment, then the heat causes problems again.

This message was edited by pauls39coupe on 1-24-21 @ 5:38 PM


srg    -- 01-24-2021 @ 9:33 PM
  Thanks Paul. I have temperature gauges for both sides and they read nearly even. Where are the thermostats? 59AB engine. I just took the radiator out and had it cored and fixed. Didn't see any thermostats.


51woodie    -- 01-25-2021 @ 3:23 AM
  srg. The thermostats, if there are any, sit on top of the hose spigot on the top edge of the cylinder head. I use 180 deg. stats in my 59AB, and it runs good with no overheating, even in slow traffic. There are several posts on here and the Ford Barn about stats, and how to secure them in place. I used short pieces of hose that fit tight inside the rad hoses to keep the stats from moving away from the spigot or turning sideways. Others put a second clamp on the hose just above where the stats sit, to hold them.
Need to figure out how to keep pics from turning sideways

This message was edited by 51woodie on 1-25-21 @ 3:28 AM


trjford8    -- 01-25-2021 @ 6:21 AM
  Do you have a ballast resistor in the line to the coil? Had similar symptoms once and it turned out to be the resistor. They break down after they warm up.

This message was edited by trjford8 on 1-25-21 @ 6:24 AM


sarahcecelia    -- 01-25-2021 @ 7:42 AM
  Ford says to run 160 degree thermostats.

"Old School guys", that raced on dirt oval tracks, used a large SS washer for a thermostat to keep from overheating. They took a washer the size of the I.D. of the top /radiator hose, drilled a 3/4" inch hole in it, and that was their thermostat. Never ,ever, any overheating problems; and they never go bad!

I learned this, "in person", from the old gent that used to run Carpenters N.O.S Department behind the main store!!

Regards, Steve Lee


Mr Rogers    -- 01-25-2021 @ 9:14 AM
  There's 2 kinds of "missing". Electronic and fuel. If you pump the pedal and experience some kind of running improvement .... sounds like carb starving. Vapor lock? Vac leak? Filter?


37RAGTOPMAN    -- 01-25-2021 @ 2:43 PM
 
My question is are you still using the resister on the inside of firewall on LS ?
the aftermarket ign system might be drawing more
causing the resister to overheat, or resister is faulty,
I would when it starts to break up , where the resister is, join both wires together so there is no resister
also you can use a jumper lead with 2 clips, to do this,
if this fixes the problem
you will have to either get a new resister or do not use one,
hope this helps, 37Ragtopman


srg    -- 01-25-2021 @ 2:44 PM
  trjford: Yes there is a resistor clamped onto the coil (right on top of the head (left side), and it does get hot due to location. I have wondered about that. Do most knowledgeable people mount the coil and resistor away from the engine?


trjford8    -- 01-26-2021 @ 6:54 AM
  On a '37 the resistor is mounted on the inside of the firewall on a fiber block just above the steering column. check to see if that resistor is still there and if connected that could be the problem. You may have the ignition wire passing through two resistors. On the later cars the coil and resistor are mounted on a steel bracket that is attached to the intake manifold at the front of the motor. Its's basically isolated from a heat source.


srg    -- 01-31-2021 @ 2:29 AM
  The old resistor on the firewall is still there, but completely disconnected. I have no vacuum lines on the car. I replaced the resistor next to the coil, no dice, that's not it. Still have the problem. Coil's next. Could bad plug wires do this? Runs great until it gets hot and then starts to cr*p out. As one of you said, this could be one (or more) of many things. It's a learning excursion and your input is appreciated. It's like a vacation, except the scenic route is through your engine.


trjford8    -- 01-31-2021 @ 7:43 AM
  At this point I would suspect the coil


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