59 A/B surges at speed

Hello folks!

I have a lot to learn about my early Ford V8 so please excuse my novice questions.

I purchased a 1941 Super Deluxe over the summer. It is a solid enough car, complete and, after some extensive mechanical work, drivable. It has a replacement 59 A/B.

I had extensive work done to it at a local shop - new carb, entire fuel system was replaced including the pump and tank and a pressure regulator was installed. They rebuilt the brake system, did suspension work, and replaced plugs, wires, points, caps, rotor, capacitor and coil. It runs, shifts and stops well but for one issue. After a few minutes driving the engine seems to start "surging". It isn't effecting drivability and it will still idle fine at stops. But I am just not confident that this is "normal".

I am wondering if I am just holding it too long in 2nd gear as when I upshift it seems to be better. I have had no experience with a car like this before so I am not sure what is normal.

The temperature gauge indicates the cool side of "normal". I do intend on calling the shop that did the work about it next week.

Any ideas on a place to start? Temp? Timing? Fuel supply?

Thanks in advance!

Feep

What carb? Are any of the fuel lines pinched anywhere? The rubber fuel line connections, do any of them look like they are possibly vacuum hose instead of fuel lines? They'll collapse if too much suction is put n them... Where's the fuel filter? Is it clean? Is it the setiment (sp) bowl type...The bowl might look clean, but check the screen..It's located up under the bowl. You'll see it when you take the bowl off. The are known to become clogged with crud/rust from the tank. With the carb you have, is the fuel pump rod the correct length?

You shouldn't have needed a new fuel pressure regulator. The flathead only needs about 3 1/2 to 4 lbs. (if I remember correctly) Stock didn't have them.

Surging is usually a sign of fuel problems not electrical nor timing.

Old Codger

Have your mechanic do a fuel delivery test,

To check fuel delivery, you need a graduated 16 ounce or larger container to determine the amount of fuel delivered in a measured time. Disconnect the fuel pump line from the carburetor and direct it into a graduated container. Crank the engine long enough to get 2 ounces of gas in the container and then continue cranking for 15 more strokes of the pump. The pump should have delivered 6 more ounces of gas.

If your pump does not deleiver enough gas, check for a clogged line from the tank by disconnecting the line at both ends, aim one end into a container and blow air through the other end. The stock line is a copper coated steel line. They can clog from rust in the tank or from the line itself rusting. You can purchase the correct line at http://www.fordscript.com/ford_bolts/products.html Mac and other vendors sell a cheaper version that will rust out in a couple of years.

Check for a collapsed flex line from the tank line to the fuel pump, by blowing through it. The ethanol in the gas attacks the rubber and it swells shut. Most vendors have an ethanol resistant hose available. The fuel pump push rod could be worn also, remove it and inspect both ends for signs of wear.

If your fuel delivery is sufficient, check the fuel level in the carburetor bowl. It should be just above the inlet hole for the accelerator pump.

Reproduction coils can also cause this problem. Most people that drive their cars a lot, have the original coil rebuilt by Skip Haney in Florida. A good ignition system will supply a 1/2" spark from a plug wire to ground at idle speed.

There is a very active Regional Group of Early Ford V-8 Club in the Washington DC area. Check out the Club at https://www.earlyfordv8.org/index.cfm They also have a Forum devoted to the 1932-1953 Ford, Mercury and Lincoln cars.