Fuel pump contacting block

[msbaugh]

I'm fighting vapor lock now that it's getting hot again. By the way I apologize in advance for my repeated beating of this dead horse.  I'm doing all I can to get this puppy running no matter what the temp is outside, that's proving to be impossible in southern Texas/Louisiana heat.

My setup consists of 3/8" lines all the way to a Holley high flow mechanical fuel pump to a regulator set at 6 1/2 psi. My fuel pressure is great, I'm trying to tune my car but after it warms up fuel pressure drops and it prevents me from moving forward. Fuel pressure gauge installed and is accurate!

No return line or electronic pump and I want to avoid putting either in if i can.  I'm insulating the hell out of the inlet line to the mechanical pump, especially by the headers.

I noticed the pump actually contacts the block. This sure isn't helping with heat. Is there a way I can shim it out or turn it slightly?

Is this a lost cause? I don't want s noisy electric pump but is that and a return line the only way to get this reliable in southern heat? I've also blocked the heat crossover and put a plastic/wood spacer under the carb

[msbaugh]

Hard to tell here... but its got some good contact.  I might try grinding a small amount down on the pump but don't think it to be such a good idea

[roadman5312]

   look at routing the fuel line away from the header heat, possibly coming outside the RS outer frame rail then in thru the inner fender @ the pump.

[cudabob496]

pump-block contact seems insignificant to cause vapor lock.

If, after warming up, I'm not sure vapor lock would reduce fuel pressure, so maybe
something else is doing that? Heat on a fuel line should raise pressure.

But for sure, keep all fuel lines away from heat.

Vent engine compartment, and a sheetmetal heat shield at base of carb could help.

Can always coil some fuel line in an ice bucket to see if solves problem.

or, http://www.summitracing.com/parts/flx-4130/overview/

I've used pipe insulation from a hardware store to keep fuel lines cool.

I your engine running hot???  That could be a factor. Too much timing advance can make header pipes hotter.

[73440]

I am dealing with the same trouble in Houston.
Added the pipe insulation on the line from the fuel pump to carb, helped a little.

Engine temp is 185 on 70* day, and the gas is boiling in the carb.

You already have the spacer,
Can the fuel vapor separator be run to a catch can rather than going all the way back to tank?

[734406pk]

Chrysler engineers were faced with this vapor lock problem back in the day and the fix was unfortunately a return line. The fuel filter had a .065 restrictor that sent some fuel back to the tank to keep the supply line cool ( well, somewhat). You may need this or a noisy electric pump at the tank pushing fuel under pressure (raising the boiling point by the way) to conquer this issue. Sorry!

[cudabob496]

I added this shield to front and back of carb, last year.
Got a 12 x 12 inch sheet of sheet metal from Home Depot.

If you're in Houston, get an alum radiator

[73440]

Did you just butt the plate to the carb? not under , correct?

[cudabob496]

Did you just butt the plate to the carb? not under , correct?

yes, I already have a 3/8 inch phelolic spacer, so butted both plates against carb, under fuel bowls.

[cudabob496]

you can also take sheet metal, bend it, and attach to your headers, or near them, to make a heat
shield, to protect components near your headers from heat.

its common on some newer cars.

http://www.bing.com/images/search?q=header+shiel&view=detailv2&&&id=6CF98770BE0C5D935CC335DE897FD9B7DEE59198&selectedIndex=110&ccid=%2bIofhVOx&simid=608024312873618932&thid=JN.Qy62I6FtQEDDc12C%2b4xW9w&ajaxhist=0

having a vented hood goes a long way too!

[734406pk]

Nice carb heat shield! New cars are EFI and the fuel supply line is under pressure, which raises the boiling point of the fuel. Unfortunately carbureted engines with engine driven fuel pumps draw fuel the entire distance from the fuel tank. Therefor the fuel supply line from the tank is under some vaccuum. If there is a suction side filter just partially restricted, will increase the vaccuum through the supply line to the pump lowering the boiling point of the fuel. Ambient heat from the engine, pavement etc can easily cause the fuel to boil into the vapor state is this case. The fuel pressure drops and the engine suffers or stalls. So two options are left. Either cool the fuel to prevent vaporization or pressurize the fuel raising the boiling point to a workable level ( or maybe both?). Also Chryler engineers located the fuel filter on the pressure side of the fuel pump to help prevent vapor lock.

[73440]

I added this shield to front and back of carb, last year.
Got a 12 x 12 inch sheet of sheet metal from Home Depot.

If you're in Houston, get an alum radiator

And then line it with Kool Mat.
http://www.koolmat.com/

[burdar]

I read that the factory put a return line on taxis and police cars back in the day. The line just went from the pump outlet right back to the pump inlet. Basically two "T's", one in front of the pump and one behind. I guess this let fuel constantly circulate through the pump. This would be easier then a return all the way back to the tank. I've never seen a picture of this setup but read about it on another site. 

[734406pk]

Possible, but I don't think this will help your situation. I've heard Aeromotive has an in-tank electric fuel pump that's fairly quite, but I haven't seen one. I have an electric pump in my Challenger and it sound like I have a blender going in the trunk. Not liking it, but no fuel delivery problems...

[msbaugh]

Ahhh the struggle is real!!!!!!!!!