Edelbrock Carb Mod

[Wesdog]

I did something different with my Edlebrock carb recently. I drilled, tapped and installed a fitting for another fuel line on the drivers side of the carb fuel inlet tube. I used Earls Performance lines/fitting and routed the fuel into this new carb fuel inlet from the electric fuelpump / filter. I then connected the fuel line coming out of the carb passenger side fitting into an adjustable regulator that has a return to the fuel tank sorta like is done with EFI fuelrail systems. What this does is maintain a constant fuel pressure at the needle&seats in the carb and circulates fuel through the carb fuel inlet tube and back to the fuel tank depending on the regulator setting. This helps keep the fuel in the carb from getting hot which helps stop any potential for vapor lock. I have a large Fram canister fuel filter mounted on the frame between the Carter elect pump and carb so I don't need the stock filter with the return line. I also put a Edelbrock thermo isolator between the carb and manifold. The carb and fuel lines stay nice and cool now. I know the stock filter does almost the same thing but I just have to try new things. I also may not have the EFI conversion done before Ouray so I want to insure I ain't gonna vapor lock there!

Edit: Here are photos:
http://www.fullsizejeeps.com/jeeps/files/Misc-Pictures/Edelbrockmods1.jpg http://www.fullsizejeeps.com/jeeps/files/Misc-Pictures/Edelbrockmods2.jpg http://www.fullsizejeeps.com/jeeps/files/Misc-Pictures/Regulator1.jpg

Wes

[ June 22, 2003, 05:39 PM: Message edited by: Wesdog ]

[jeepguzzi]

send me send me!!!
larrynlella@attbi.com

[AMX factor]

did you remove the float from the pasenger side so that the fuel can go out that side? If the float is still there it will just raise and stop the fuel from exiting the bowl. I'd be interested in specs also. Novel idea but need more info.

[JAllenWAG]

I have been trying to find a way to vent my edelbrock 1406 to the vapor canister because I think that would help solve my vapor lock. Do you think drilling a hole somewhere and putting in a fitting would allow me to do this?

[AMX factor]

You're 1406 should have the bowl vent already. Just run a tube to the vapor canister. I did that when I was running a Carter AFB 9600 series carb. I switched to the Edel 1405 which has no bowl vent emissions. For vapor lock reduction install a phenolic or wood carb spacer and route all gas lines so they don't come in contact with any other metal pieces. Try and use as little of the rubber hose as possible, it just absorbs heat, steel will actually dissapate some heat.

[Wesdog]

Originally posted by AMX factor:
did you remove the float from the pasenger side so that the fuel can go out that side? If the float is still there it will just raise and stop the fuel from exiting the bowl. I'd be interested in specs also. Novel idea but need more info.The only mod I did to the carb was to drill and tap a 5/8" 18 threads/inch hole where the driver's side of the carb inlet tube is normally plugged. Didn't touch the 2 fuel bowls, needle, seat or floats. The fuel inlet tube is a passage that runs from the carb fuel inlet fitting to both needle & seat openings. The passage is plugged on the drivers side. The correct tap size is 5/8" 20 threads/inch for the new fitting but a 5/8" 18 hole works. I did not alter the needle&seat inlets to the fuel bowls in any way. Fuel from the Carter 72gph electric pump flows through a Fram canister filter and into the drivers side of the carb fuel inlet tube. It then flows out the passenger side of the fuel inlet tube and to the regulator inlet. The regulator returns fuel to the tank as necessary to maintain the fuel pressure on the inlet side (in the carb inlet tube) to the desired setting up to the maximum fuel pump pressure. The carter pump puts out about 7 psi and I have the regulator adjusted for 4psi. I have a mechanical pressure gauge in the cab with an isolator installed on the regulator for monitoring fuel pressure.All hoses are heat shielded and are high quality Earls Supply braid and half style. I used Earls swivel seal fittings. I had to install a 5/8" spacer between the aircleaner and the carb so the aircleaner would clear the fuel line on the drivers side. I used metal one made by Carter that is carried by Summit Racing. I don't like the plastic ones Edelbrock offers.

Wes

[ July 18, 2003, 07:10 AM: Message edited by: Wesdog ]

[Wesdog]

Originally posted by JAllenWAG:
I have been trying to find a way to vent my edelbrock 1406 to the vapor canister because I think that would help solve my vapor lock. Do you think drilling a hole somewhere and putting in a fitting would allow me to do this?To my knowlege, vaporlock can occur in the fuel lines and the carb fuel inlet tube between the 2 float bowl needle & seat inlets, but not in the carb fuel bowls because the bowls are vented. However the fuel in the bowls will boil if the carb gets hot enough and that is a serious problem also. The bowls are already vented so the vapor can escape that area the only variable is whether there is a bowl vent tube you can hook a hose to for routing the vapor to the charchol canister. When the fuel boils in the fuel lines or carb inlet tube there is nowhere for the vapor to escape to and let liquid fuel in unless you have the stock fuel filter with the little 1/4 nipple return to the tank. Fuel will continuously flow through the fuel lines and return to the tank if you have that setup. The exception is the fuel in the line between the filter and the needle&seat bowl inlets. There is still the possibility of vapor lock in that area but it is much reduced if you have the filter with the return because the flow of fuel helps keep it cooler.

There is very little room under the hood for raising the aircleaner 5/8" as I mentioned above. I have a 2" body lift which provided the necessary additional hood clearence so I could install the 5/8" spacer. The Edelbrock Performer intake raises the carb a little also I think and so would an isolator under the carb. As far as the aircleaner interference you could probably make a dent in the underside of the aircleaner base so it would clear the new hose/fitting. Depending on the type of fitting used it might not even be necessary to do that.
I have 2 additional things to pass along about the Edelbrock Carbs:

1. If you install the offroad needle & seat: (Off-Road Needles and Seats (pair) #1465, includes a pair of spring loaded needles and .0935" seats.) watch out for the float level adjustment. When I set it per the spec sheet that came with the offroad needle&seat it leaves the fuel level in the bowls too low for correct accelerator pump operation which results in a bog in takeoff/acceleration. This is because the fuel pressure has to overcome the needle/seat spring pressure that is present when the float level is set. Others may have opinions on this but my observation is that it will be a trial&error float level setup. Make sure the accelerator pump is working correctly with the stock needle&seat/float level and then install/adjust the float level with the offroad needle and seat until the bog is gone. You will have to decrease the 7/16" setting to raise the fuel in the bowls to the level to get the accelerator pump working correctly.

2. I used the Edelbrock Divided Square-Bore Heat Insulator Gasket (0.320" thick) #9266 or(Square-Bore Heat Insulator Gasket (0.320" thick) #9265 if you have an open plenum intake) and it seals well on my Performer intake.

http://www.edelbrock.com/automotive/index.html

Wes

[ June 19, 2003, 10:37 PM: Message edited by: Wesdog ]