Fuel Return line for Sniper EFI

[elroberds]

So my plan is to go with the 2GC Sniper EFI unit for 2 reasons. One is that I want to retain the factory style air cleaner and two the brake master cylinder on the earlier models is to the left of the ribs on the firewall as you look at it and I believe it will interfere with the 80 series master brake cylinder when I go install it as I add front disc brakes. ( I could be wrong).
On my 55- 05/70 production date there isn't a charcoal canister or fuel separator. Only the two vent lines that come from the top of the tank back to the filler neck.
On the sniper instillation instructions it has the fuel return line coming back to the tank ( you have to drill a hole in the top of the tank).. What are my options if I do not want to drop the tank? Can I splice into one of the vent lines or add a third return into the filler neck?

 

[sahelzer]

I recall reading on Holley forum you want the fuel return to drain back into the tank at bottom of tank. This prevents frothing of the fuel. So I guess return at top with outlet tube to bottom of tank.

 

[scrapdaddy]

If I remember right you have four vent lines, one on each corner of the fuel tank on the early models running to a fuel separator mounted behind the cargo panel. You might be able to tap into the tank at the trap door where the the fuel float is. Run a line down inside the tank if need be?

 

[elroberds]

If I remember right you have four vent lines, one on each corner of the fuel tank on the early models running to a fuel separator mounted behind the cargo panel. You might be able to tap into the tank at the trap door where the the fuel float is. Run a line down inside the tank if need be?

Mine doesnt. I believe that Pre- 07/70 have only the two vent lines that are on the filler neck. Not sure when the change happened to the 4 vent lines. I didn't think about the trap door, but instructions say to avoid the sending units. I would also be worried a metal shavings.


@sahelzer I recall reading on Holley forum you want the fuel return to drain back into the tank at bottom of tank. This prevents frothing of the fuel. So I guess return at top with outlet tube to bottom of tank.

Install instructions photo show a top mount with a tube hanging down into the fuel cell.

 

[scrapdaddy]

Mine doesnt. I believe that Pre- 07/70 have only the two vent lines that are on the filler neck

Those two lines are over flow lines, they are bigger in dia. than the vent lines. My 71's have those two lines and the four vent lines. Take a look up at the tank you should be able to see the lines coming together.

 

[elroberds]

Those two lines are over flow lines, they are bigger in dia. than the vent lines. My 71's have those two lines and the four vent lines. Take a look up at the tank you should be able to see the lines coming together.

I do not believe mine has the 4 lines coming out of the tank. I can reach up and feel nothing/ see nothing. There is not a fuel separator- I don't have the rear covers, never been on the 55 since I have owned it. I also do not see any openings in the side for other hoses to come through.

 

[elroberds]

I found this photo online of a 55 gas tank for sale in 2018. It has 4 vent lines coming from the corners. Checked mine to see if those were there and they were not.

 

[scrapdaddy]

Yeah, that's what I was referring to, mine are like that one. That's all I got.

 

[elroberds]

Yeah, that's what I was referring to, mine are like that one. That's all I got.

I have found that mine pre 07/70 has many differences. Looking at the SOR website they don't offer a fuel separator for anything earlier than 09/72. What would you think about adding the return to the filler neck? Or does it really need to be in the top of the tank?

 

[scrapdaddy]

I don't have an opinion on that one, don't know anything about what the sniper requires. I don't like the idea of a return line there, just doesn't seem right. If it were me, I'd probably drop the tank and have a return nipple put in.

 

[elroberds]

I don't have an opinion on that one, don't know anything about what the sniper requires. I don't like the idea of a return line there, just doesn't seem right. If it were me, I'd probably drop the tank and have a return nipple put in.

You are probably right. It is just a bit of work. That would probably put me in PO status.

 

[PabloCruise]

I have found that mine pre 07/70 has many differences. Looking at the SOR website they don't offer a fuel separator for anything earlier than 09/72. What would you think about adding the return to the filler neck? Or does it really need to be in the top of the tank?

Are you thinking about splicing into the 2 overflow lines that join the filler neck?

I don't have an opinion on that one, don't know anything about what the sniper requires. I don't like the idea of a return line there, just doesn't seem right. If it were me, I'd probably drop the tank and have a return nipple put in.

If he is inclined to drop the tank, and he has a good radiator shop nearby, I would agree. If he were trying to skip that step (it is a PITA to drop the tank), I would be inclined to try splicing into the overflow line at the filler neck.

 

[PabloCruise]

I have not seen a pre 7-70 Pig and seen the fuel set up, but if you really do not have a charcoal cannister, you might want to think about adding one.
You are adding an electric fuel pump, yes?
Moving more fuel around and returning fuel at an elevated temperature (from pressurizing and routing up to the engine compartment) means you will be making more vapors.
Those vapors need to go somewhere. And they will. And they smell unless you capture them in the charcoal and then burn them.

 

[elroberds]

Are you thinking about splicing into the 2 overflow lines that join the filler neck?

If he is inclined to drop the tank, and he has a good radiator shop nearby, I would agree. If he were trying to skip that step (it is a PITA to drop the tank), I would be inclined to try splicing into the overflow line at the filler neck.

That was what I was thinking. The holley site for the 2GC instillation says to not route the fuel return line to the charcoal canister.

From Holley-
DANGER! Do not use the vapor canister lines as a fuel return line. Possible fuel leaks may create a fire or explosion hazard, causing serious injury or death. DANGER! Proper installation of the fuel return line will necessitate complete removal of the fuel tank. This work should be done by a fuel tank specialist, who regularly does this work and is familiar with safety regulations and precautions necessary to do this work. If a person attempts this work, who is not familiar with the safety regulations and precautions, an explosion hazard may result causing serious injury or death.

 

[NikP]

I have the same tank with two large hoses and nothing else. Tapping into the overflow lines shouldn't be an issue. I drop my return fuel in via the top of the tank for my LS swap and haven't had any issues specific frothing.

 

[elroberds]

I have the same tank with two large hoses and nothing else. Tapping into the overflow lines shouldn't be an issue. I drop my return fuel in via the top of the tank for my LS swap and haven't had any issues specific frothing.

Great. Thanks. The next time I am back in my hometown (Aztec) I will need to swing by and check out your 55.