PurpleBeeper
Well-Known Member
Fuel line covered in thermosleeve in engine compartment and along the frame rail
Cool Can for Fuel
- Thread starter PurpleBeeper
- Start date
PurpleBeeper
Well-Known Member
Stock fuel tank with dual outlet sump. Fuel pumps above differential (Holley blue - less than 5000 miles on it). 3/8” alumninum fuel line routed next to factory fuel line. Regulators on passenger inner fender. Fuel line wrapped in thermosleeve. From regulator, rubber hose (with thermosleeve) running to factory 5/16” six pack fuel lines
padam
Well-Known Member
The axle travels a lot, can smack that pump.
Don’t ask me how I know.
PurpleBeeper
Well-Known Member
The pump seems to be fine. The tiny air fuel leak sucking in air makes sense, but I saw the fuel boiling inside the clear fuel filter with the engine & pump turned off (after driving, I shut off the car, opened hood and looked). I’ve had vapor lock trouble with this car for years (got home one night with a rag full of ice on the center carburetor). The oil cooler idea is interesting. The return line may be better (?). I’m considering a cool can as an emergency backup if I’m hundreds of miles from home (I can find ice). I do have a phenolic spacer on the way. Any other ideas?
My Sixpack is on a small stroker, my whole system is stock. Never have had a vapor lock problem. You might start looking there, do not remember having vapor lock problems way back when. Except in very high heat and humidity, sitting in the staging lanes at the drag strip.
padam
Well-Known Member
If I’m not mistaken, increasing pressure should raise the boiling point.
Years ago I had vapor lock problems and solved it by using an electric fuel pump only, rerouting the lines away from heat, and a nylon carb spacer.
I run 7 psi and have had to replace two fuel pumps in the last 2 years when they wouldn’t hold that pressure.
Years ago I had vapor lock problems and solved it by using an electric fuel pump only, rerouting the lines away from heat, and a nylon carb spacer.
I run 7 psi and have had to replace two fuel pumps in the last 2 years when they wouldn’t hold that pressure.
When puhing fuel using an electric pump there should be no vapor lock. The issue stems from trying to pull fuel up and forward. Relocate the pump down and to the rear. Ive used Holley blue many times mounted this way with aluminum line. No wrap on the line either. Never had an issue.
Doug
Doug
Keeping the fuel moving prevents vapor lock. A filter close to the carb with a return port back to the tank takes care of it. The 6 Pack cars had a vapor separator and return line.
if the OP has the fuel pump already mounted above the differential, how is this hurting him since it's already towards the rear of the car and what exact location further down and rearward should he move the pump to? I've never run an external electric pump, but usually see them mounted on the rear framerail outboard of the exhaust - is that where you recommend or somewhere else?
If the pump is mounted in that ideal rear location, could this problem still surface if it's a deadhead setup (meaning a return line is still advised)?
I cringe when I hear people say I have a glass gas fuel filter over top of the engine especially one that is boiling gas in it. Over time the O-rings shrink and expand from going through the exact heating and cooling process you describe and then that glass filter sprays fuel all over the hot engine especially one that has an regulated electric pump... I would be removing that filter BEFORE a fire breaks out driving down the road...Put a filter back at the tank and if you wanted to put a good small filter right put it right before the regulator. Why have all the debris flow through the pump and the regulator BEFORE being filtered out? Does this just have a stock fan on it? What temp does it run at? If a stock fan and it builds heat under the hood after it's shut-off you could maybe switch to electric fans so it keeps cooling under the hood instead of building heat... I had issues with my '64 even with a electric pump but only on REALLY hot days. Sometimes I would get caught in traffic and I had to actually put the heater on high...
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In it's current location the pump is pulling fuel forward and upward from the tank. Electric pumps push fuel very well. They do not pull fuel very well. We try to mount them inside the frame rail just forward of the bumper. Gravity feed from the tank is the best. Behind the tank aloows G force on accel to help fill the pump. None of the street cars I've built use return systems. Most of the drag cars didn't either. My current drag car (900hp) uses return from the pump to the tank right at the tank itself. With a rear regulator sending
30 psi forward and then reguated down to 5 1/2 psi near the carbs. But that is way more high end stuff than needed in most cases.
Doug
thanks. Wow, not much room between the rear bumper and rear of the tank. Makes sense though.
Here in California we have very high ethanol content in our fuel. It makes fuel boiling in the carb a problem on shut down. Adding a return line solved my problem and can't hurt the situation the OP is having.
ozzymaxwedge
Active Member
Yep, do what DVW Doug said, they are a pushing pump not a pulling pump, get rid of that glass filter and insulate lines from hot area’s.
flyingfeathers
Well-Known Member
Cool can should only be used for racing you have other problems! 
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