I need help with a '35 Flathead engine issue

wingerdinger

wingerdinger

Member
I have a 1935 Ford Big Truck, with the 85HP Flathead V8.
I am having trouble getting it to run properly.
I have owned this vehicle a short time, and when I got it, it didn't run, and all I did initially was to swap battery posts because it was wired backwards, and clean the coil terminal for spark.
It ran, so I decided to pull the heads to inspect things. The heads were non-original (aluminum), so I bought heads, had them cleaned and surfaced, and installed them. I rebuilt the carburetor and fuel pump and cleaned the gas tank.
Now, when cold, it runs terrific. However after driving maybe 3-4 miles, once thoroughly warmed up, it begins to misfire, and I am unable to get any power after about 1/3 throttle.
I dismantled the carb, and replaced the jets with slightly larger ones, power valve and accelerator injection tubes. Not much change.
Any ideas????



 
Have you changed the ignition condenser? They do go bad and effect is very close to your symptoms. Miss and stalling when warm. NAPA sells a good condenser I believe most are using the IH200. You have to do a bit of modifying to get it to fit the 33-36 distributor or the FA5 without modifying.
 
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It does sound like the classic bad coil or condenser issue.
Gets warm/hot, starts missing.
 
I would check the coil, resistor on firwall behind dash, and condensor as Terry mentioned. These components could all work fine at ambient temperatures, but produce the problem you discribe when heated to engine operating temperatures.
Buying new reproduction replacement parts, with some or most coming from offshore sources, may be no better than what you have now. This could also be true for NOS replacement parts because of degradation of 80+ year old insulating materials.
 
I recently ran into the same issue. Turned out to be a vacuum leak. I didn't have anything plugging up the vacuum hole where the wiper motor connects.
 
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