248 Problems!!!

[1LOWBUICK]

I dont know what the deal is but i hope you guys can help.
i've had this 1950 56r for 7 years now and out of nowhere problems.
when i drive a few hours to a show about half way it quits it sputters like its out of gas.i then pullover put it in park and it starts right up. drive a few more miles and it will do it agan and seemes to get worse the longer i go. i stop to let it cool off and its good. so we thought it was gas vapor lock (it might be) so i put a 5/16 rubber hose up high along the fire wall over the wiper motor up and away from the heat. but on the way home a hour in to it it quits agan. so i put on a new coil and new ballast resistor and new spark plugs (buy not wires). same deal. when i got home so i thought the sending unit beacuse i put in a new gas tank but not a sending unit so i put a new one in same deal. i put on a new electric fuel pump thats 4-5 p.s.i. and filter 8" from tank and all new gas 5/16 gas line. changed glass filter before carb and checked the little filter in the cartter carb. still no luck so i tried the key switch i put a ron fransis switch on and a ford solenoid . the starter was rebuilt this passed winter (the car is 12V for years now) i can run all day at 45 55mph and 190temp in town with no problems its when i hit the highway after a hour but only sometimes beacuse i on sat i drove 1 1/2 hours with nothing but on the way home the next day it stoped agan. its not a big deal cause i'm in town most of the time but in 3 weeks i go to chicago and i dont want the rest of the guys to have to pullover with me. i'm at a loss i've done what i thought would work.

the only thing i havent done is rebuild the carb i have the stuff to do it and a carb spacer. mabye the floats stick at "high speed" and suck all the gas out of the bowls? and as soon as the motor stops they fall down and then gas gets in and i start up? i dont know.

my buddys 50 pontiac has a carb heat sheild i might put one on mine

all i can think is the gas is boilling in the bowls or at 65 the spark and or fuel cant keep up? but why is this starting now? the temp stays the same i check with my $150 laser temp gun so i know its not to to hot never over 200.

thanks for any help
dan

my wife told me to put all dumb face things sorry

[OOPSETTER1]

Is your mechanical fuel pump still on the car, or at least in working condition? When I first got my '49 Super, the previous owner had put an electric fuel pump on the frame just foward of the fuel tank (which is where they are recommended to be installed, since they "push" fuel instead of pulling from the tank). My mechanical pump had been bypassed, and was only left there to give the wipers vaccuum. My car was converted to 12 volts too, by the way. Long story short, I had the same problem that you're experiencing, it turned out that the 12 volt electric fuel pump was overheating and stopping. I could let it cool off for 30 minutes or so, hop in and drive again...for a while. I replaced the electric pump four times, and then I started getting curious. I hooked the fuel lines back up to the mechanical pump...it proved to still work well. I only use the electric pump now as a starting aid when the car has been sitting for a week or two. When your car dies, can you still hear the fuel pump running with the ignition switch on? Try feeling of the pump to see if it is overheating.

[1LOWBUICK]

oopsetter1 thanks for the reply

i think the pump is running but then agan it only breaks down on the hiway so their is lots of noise. i wonder was your pump a "cheep 1" in the $45 $50 range mine is. i wonder if a "real" one from summit would be better? its mounted just behind the rear end and i dont want to get my good t-shirt dirty so i never felt it i guess i could take off my shirt and get my fat butt dirty and check.
my mechanical pump is mounted but not hooked to annything my wiper is rain-x
i can rebuild my pump and use it to thats a good idea.
a buddy told me i should put on a mechanical "clicker" pump? he said its the best.
would your car start right up if you tried? even if you diddent let it cool

thanks

[ebbsspeed]

I suspect you have a plugged gas tank vent. After you pull so much fuel out of it, the pump can't overcome the vacuum in the tank.

[OOPSETTER1]

would your car start right up if you tried? even if you diddent let it cool

thanks

No, my car would not start again for at least a half hour. Ebbsspeed had a great suggestion too, check the vent tube on your tank.

I think that part of my problem was a bad needle and seat in the carb too. When my car would quit (always at speeds of over 45 mph), I could remove the gas line at the fuel filter and let the pump run and push some fuel through the line, replace the line, and she'd fire right up.

I was using quality electric pumps, costing quite a bit. I got one (I wish I could remember the brand name) that sounded like a boat motor when it was running...LOUD! It didn't last very long either. All the pumps were in the 3 to 5 PSI range, these cars don't need much fuel pressure.

Looking back, my problem could have been the bad needle and seat in the carb creating too much back pressure for the pump to work against, thus burning them up. I had my carb rebuilt in the midst of all the problems, so it's hard to pinpoint exactly what was doing it. I know I went through a lot of fuel pumps when the car was running on the electric only.

[OOPSETTER1]

All the electric pumps I went through also had a filter on them, you could check that one too. While I was having all the problems, I also dropped my tank and had a local radiator shop to clean it.

[1LOWBUICK]

I suspect you have a plugged gas tank vent. After you pull so much fuel out of it, the pump can't overcome the vacuum in the tank.

thanks eddsspeed

i put a new tank last year and drove to chiacgo with no problems with the old sending unit. it wasent untel this year problems started .so i put in a new sending unit from cars inc. two weeks ago. as i think back their is no vent on the tank or in the sending unit. would takeing the gas cap off do the same thing? i know its not the best idea but i only need to do this 2-3 times a year for a few hours. or could my old gas cap vent not be working?

[ebbsspeed]

Taking the gas cap off would relieve any vacuum issue. If it is indeed the problem, you will hear a whoosh of air rushing into the tank when you crack open the cap.

[Spud]

I had the same problem with a old Harley I have. The vent in the cap was plugged, it stalled took the cap off to see if I had gas started back up, on the way home when it started to stall I would just crack the cap.

[1953Special]

I think you are on the right track with a carb float problem. I would definitley have the carb rebuilt. Also may want to check the small rubber fuel line from the fuel tank to the main metal line. If the rubber line is cracked or old it may be causing poor fuel delivery when it gets hot.