Running without vacuum

kraken

kraken

Member
A friend of mine has a '47 with a fairly stock flathead. It has been running great, but now it will quit after warming up and running about 20 miles. He thinks its the carb, or its vapor lock. Since he has an electric fuel pump, I don't think it is vapor lock. I suspect the coil, even though it is new. I want to run his stock carb on my '50 Ford to see if I can get it to fail. I know it won't run great without vacuum, but is it worth trying?

Thanks.
 
Ditto coil and/or condenser as most likely suspect.

But just to be sure, when it dies, pull off the air cleaner and peer into the throat of the carb; full stroke the throttle and look for a nice stream from the accelerator pump discharge tubes into the top of the venturis. If it is just a dribble or spitting, you have a fuel problem. Next step, disconnect the fuel feed line to the carb, stick it into a jar, and crank the engine with the ignition off or coil wire disconnected from the coil (not from the distributor!). The gas line should put out a sizeable spurt with each revolution of the cam. If not, you may have a pump or vapor lock problem. If the pump is good, you may have a sticking needle valve at the carb fuel inlet.
 
He is running a 12 volt pertronix ignition, so there is no condenser. I am assuming that running a electric fuel pump would eliminate any vapor lock problems. I am leaning toward the coil. He took the carb off, and brought it over to me - the car is about 30 miles away. Just to prove to him that its not the carb itself, I was going to run it on my '50 and see if there were any problems. Since his carb does'nt have a vacuum port, will it still run good enough to test the carb? When we get it back on his car, I will check his electric fuel pump to make sure it is not the problem.
 
It will run well enough to test. Maybe advance your initial timing a little to compensate some of the lack of advance.
 
I have never had vapor lock ever, in florida. Never....ever... stop go 100 plus. Cool block though.

I run a simple 6v setup. Yes I'll do the standard fordbarn post: skip coil, bubba dizzy (skip did the dizzy on my 36 and it runs great) and the ih200 napa condenser. I'm running a eth safe pump (even though I never use corn fuel in the vehiclesw) from dennis. I run 97s, one new 97 that did give a little trouble and one I had rebuilt from a local racers.

it's been 4 yrs now (knock on wood) but I really have no issues. When I first started, I had a hard time getting it all to work together, my goal was to have a stockish setup. No thrills. Just solid.

I know that some of the electric timing dizzys do open an engine up. I'm not pooping on that. Just relaying my experience on a basic rebuilt setup. I really feel surprised when I walk out to the shed and the car starts after a few cranks with the choke pulled. Sometimes a month or more.
 
kraken said:
He is running a 12 volt pertronix ignition, so there is no condenser. I am assuming that running a electric fuel pump would eliminate any vapor lock problems. I am leaning toward the coil. He took the carb off, and brought it over to me - the car is about 30 miles away. Just to prove to him that its not the carb itself, I was going to run it on my '50 and see if there were any problems. Since his carb does'nt have a vacuum port, will it still run good enough to test the carb? When we get it back on his car, I will check his electric fuel pump to make sure it is not the problem.
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12 volt pertronix that quits after 20 miles usually is two low of resistance in the primary caused by resistor/coil etc. I am assuming it has no spark output when it dies. Low resistance causes high current and high current causes high heat. After some run time the units electronics just shuts off. The pertronixs doesnt like much over 8 amps !! Example : A .5 low resistance coil would draw 24 amps !!!!
In our shop we are sounding like a bunch of crows most of the time : coil-coil-coil..:)
 
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