Dr. Marneaus
Station Wagoneer
As you mentioned, many people have issues with hot fuel in carbs.
I had already done a few things to mitigate the issue, number one being a 1" phenolic spacer under the carb.
number two being re-routing some fuel lines.
number 3 being replacing the tank with the OEM unit (away from the exhaust) and hooking up the vent lines correctly to the vapor canister and whatnot.
Unfortunately, in 73 they didnt come rigged for a fuel return line from the filter at the carb, which keeps fuel cooler by allowing it to constantly circulate. That may or may not get installed eventually, if/when i drop the tank again (I'd have to install a fitting in the tank, thats the only real issue).
So, one supposedly major contributor is the fact that these old 360's have a mechanical fuel pump mounted on the motor. This not only requires you to run lines close to the motor, but also the pump itself gets warm. ALSO, a mechanical pump is a puller, not a pusher. It sucks the fuel from the tank and then only has to push the fuel about 2' up to the carb. This applies a vacuum to the fuel, lowering the pressure ever so slightly, but also decreases the boiling point, and allows the fuel to heat up faster. Plus you have the issue of hard starts when the truck is warm because you need to crank the engine to prim the carb after fuel may have boiled off from sitting.
Well, sounds like there is a good solution to this!
Delivered to my door in less than 2 days! Thank you, Summit Racing! (shameless plug for a great company with great service!)
Holley red baby! 20' of braided stainless steel 3/8" fuel line! Aluminum fittings! Mechanical pump block off for chevy style pumps! Relay plug/wire kit. Oh and a High Life....yum!
Advantages to an electric pump:
Electric pumps are pushers. Mounted as close to the tank as possible, it will push (read: pressurize....i'm not talking about anything above a few PSI) cool fuel from the tank all the way up to the carb.
Primes the carb when I turn the key, not when I start the engine.
Its loud as hell so I can tell its running, and I can hear what it's doing (may not be an advantage but why focus on the bad?)
Allows avoidance of the heat of the engine by circumventing the mechanical pump and allowing you to route the lines where ever the heck you want.
So the old lines ran along the frame, crossed over to the engine at the front just behind the power steering pump, up through the fuel pump, then across the top of the timing cover over the valve covers, then around the back of the carb (right on top of the intake manifold). hot hot hot!
So, i mounted the pump up out of the way on the rear crossmember, just behind the tank. this is about 24" away from the fitting for the fuel pickup on the top of the tank. The closer you can get it, the better. Technically you're supposed to try and mount the electric pump below the lowest point of the tank, in the event that it loses prime it will always have gravity to feed it. Well, that doesnt work on a 4wd like this, because the gas tank itself is one of the lowest points on the truck, im not about to put my fuel pump lower and in harms way.
I could have placed it at the front of the tank, a little lower, but this put it further away from the tank, thus increasing the risk of losing prime, but there wasn't really anywhere I could fit this holley up there.
Also looked at mounting it on the outside of the frame, up under my rockers. But.....it just didnt sound smart to me to have fuel lines and wiring for a pump running along the outside of my frame...in an area constantly wacked by bushes and branches and potentially rocks and other hard items.
So, up above the rear axle it went.
i ran the braided line along the same route through the frame as the original lines, but insted of going up to the front of the motor, i pulled it up the firewall, next to the tranny hump, mounted it along the top of the firewall near the cowl to cross over the engine, and then finally broke away from the firewall for about 18" to reach the carb.
now that I was running a rear fuel filter as well i wasnt as worried about the servicable filter in the front, plus i know how to work them now to make sure they aren't loose haha. I wanted a filter that I could visually inspect, and see if fuel was moving through. Its nice to have a window into your fuel system sometimes.
After installing and wiring the pump I also tried to clean up my other accessory wiring a bit, installed some circuit breakers rather than running to the battery, and also ran everything that was crossing the firewall in split loom (you can see it in this pic running off towards the carb). I need to cover or enclose the circuit breakers eventually. I've seen some neat stuff done with little pelican cases that are water tight, and may get there eventually.
I had already done a few things to mitigate the issue, number one being a 1" phenolic spacer under the carb.
number two being re-routing some fuel lines.
number 3 being replacing the tank with the OEM unit (away from the exhaust) and hooking up the vent lines correctly to the vapor canister and whatnot.
Unfortunately, in 73 they didnt come rigged for a fuel return line from the filter at the carb, which keeps fuel cooler by allowing it to constantly circulate. That may or may not get installed eventually, if/when i drop the tank again (I'd have to install a fitting in the tank, thats the only real issue).
So, one supposedly major contributor is the fact that these old 360's have a mechanical fuel pump mounted on the motor. This not only requires you to run lines close to the motor, but also the pump itself gets warm. ALSO, a mechanical pump is a puller, not a pusher. It sucks the fuel from the tank and then only has to push the fuel about 2' up to the carb. This applies a vacuum to the fuel, lowering the pressure ever so slightly, but also decreases the boiling point, and allows the fuel to heat up faster. Plus you have the issue of hard starts when the truck is warm because you need to crank the engine to prim the carb after fuel may have boiled off from sitting.
Well, sounds like there is a good solution to this!
Delivered to my door in less than 2 days! Thank you, Summit Racing! (shameless plug for a great company with great service!)
Holley red baby! 20' of braided stainless steel 3/8" fuel line! Aluminum fittings! Mechanical pump block off for chevy style pumps! Relay plug/wire kit. Oh and a High Life....yum!
Advantages to an electric pump:
Electric pumps are pushers. Mounted as close to the tank as possible, it will push (read: pressurize....i'm not talking about anything above a few PSI) cool fuel from the tank all the way up to the carb.
Primes the carb when I turn the key, not when I start the engine.
Its loud as hell so I can tell its running, and I can hear what it's doing (may not be an advantage but why focus on the bad?)
Allows avoidance of the heat of the engine by circumventing the mechanical pump and allowing you to route the lines where ever the heck you want.
So the old lines ran along the frame, crossed over to the engine at the front just behind the power steering pump, up through the fuel pump, then across the top of the timing cover over the valve covers, then around the back of the carb (right on top of the intake manifold). hot hot hot!
So, i mounted the pump up out of the way on the rear crossmember, just behind the tank. this is about 24" away from the fitting for the fuel pickup on the top of the tank. The closer you can get it, the better. Technically you're supposed to try and mount the electric pump below the lowest point of the tank, in the event that it loses prime it will always have gravity to feed it. Well, that doesnt work on a 4wd like this, because the gas tank itself is one of the lowest points on the truck, im not about to put my fuel pump lower and in harms way.
I could have placed it at the front of the tank, a little lower, but this put it further away from the tank, thus increasing the risk of losing prime, but there wasn't really anywhere I could fit this holley up there.
Also looked at mounting it on the outside of the frame, up under my rockers. But.....it just didnt sound smart to me to have fuel lines and wiring for a pump running along the outside of my frame...in an area constantly wacked by bushes and branches and potentially rocks and other hard items.
So, up above the rear axle it went.
i ran the braided line along the same route through the frame as the original lines, but insted of going up to the front of the motor, i pulled it up the firewall, next to the tranny hump, mounted it along the top of the firewall near the cowl to cross over the engine, and then finally broke away from the firewall for about 18" to reach the carb.
now that I was running a rear fuel filter as well i wasnt as worried about the servicable filter in the front, plus i know how to work them now to make sure they aren't loose haha. I wanted a filter that I could visually inspect, and see if fuel was moving through. Its nice to have a window into your fuel system sometimes.
After installing and wiring the pump I also tried to clean up my other accessory wiring a bit, installed some circuit breakers rather than running to the battery, and also ran everything that was crossing the firewall in split loom (you can see it in this pic running off towards the carb). I need to cover or enclose the circuit breakers eventually. I've seen some neat stuff done with little pelican cases that are water tight, and may get there eventually.
Running but trans was shot I guess! 
