Vapor locked

[bran3b]

Can I install an electric pump in series with a performance mechanicel pump? I seem to be having a vapor lock problem after driving a little, then shutting down for a few minutes, then trying to start back up. I was thinking that an electric pump, even a cheap one, could keep the mechanical pump filled with liquid fuel.

Bran

[427sharpe]

ABSOLUTELY! Suggest mounting the electric pump as close as possible to the tank and as low as you can, because elec pumps like to 'push' but hate to 'pull' fuel. Just make sure you get a pump set for carb and not fuel inj--there's a HUGE pressure difference!

[Coloradocobra]

Hi Bran,

Are you running a carb spacer? I don't know how much clearance you have with the 460 but a 1" or even 1/2" spacer may help to keep some of the heat out of the carb. Also, check where you are running your fuel lines to the pump and from the pump to the carb to make sure they are as far away from major heat sources as possible. With our high altitude and the newer fuels, vapor lock is a real problem. I run a mechanical and have never had any pressure/flow problems or vapor lock so far.

My carb problem was similar except I was having float problems. After only minor heat soak, the floats were not keeping the needles properly seated and I ended up with too much fuel - everywhere. New off road seats from Holley have correct this issue - so far. After you get your car hot, let it idle and take the air cleaner off. Grab the roll bar and shake the car as hard as you can and look for fuel spraying up through the vent pipes.

Call me if you need any help. We don't want it to vapor lock on the dyno on the 20th!

Gary

[SCOBRAC]

Are you running a gas cap in the filler neck in addition to the Le Mans cap (filp cap)?? If you are it, or your tank, must be vented. If you have a screw cap, take it off, try it then.. If you need to drill a small hole in the center of the cap. .125"-.1875" 1/8th-3/16".. or just leave the screw cap off if it doesnt splash too bad..