fuel return lines

[island45]

So, the short version is I'm gonna switch carbs and dizzys from my '76 donor with my '79 pig..The pig has a low mile matched set specter non-usa carb and dizy that I installed not too many miles ago. Problem is, the '76 has a return line off the carb, and the '79 has it off the fuel pump. Do I switch pumps too? And the donor '76 engine will be transplanted into my '66 fj45 soon, and it has no provision for a return line into the tank. I'm thinking I should either run an electric fuel pump to the '79 carb with no return at all, or plumb a fitting into the '66 tank for a return..... confused? I am... and whats up with black type?

 

[island45]

Well, I guess nobody knows the answer to this one. I'm thinking as long as i get the excess fuel back to the tank it will be 6 of one half dozen of the other. What do other guys do when you put a 2f with return line returns into an early rig with no provision for it in the tank? The last time I did this was about ten years ago and I put an aisan 1 bbl on it and I dont remember what I did with lines. Also, my screen still shows black type on a black background, so I guess I'll try the help section for that one.

 

[PhrogsPhorever]

 

[spotcruiser]

Hey Gary, is the text color just a problem on your posts or all posts? You can select text color for your posts in the "reply" screen.

Don't know about the return fuel line. I guess you can bend your own. Seems like you'll need some sort of screw-in fitting for the tank. Do not weld on the tank without taking special precautions to "inert" the tank. Welding on a tank is very dangerous. Tor blew one up a couple of years ago.

 

[FJ40Jim]

Island, you've 3 or 4 different vehicles,carbs, fuel lines in your post. I dunno what you're doing.

But here's how to do it.

If using a 73-earlier fuel tank w/ no return, then use a 78-earlier fuel pump and plug the return bolt at the carb (use the 70-73 return plug on 74-76 carbs, use the 79 return plug on 77-78 carbs)

if using a 74-later fuel tank and 79-later carb, then also use 79-later fuel pump.

HTH

 

[island45]

I told you it was confusing!... I've already swapped the dizzys and I just wanted tp swap the 76 and 79 carbs with each other. I am sort of dialing in and desmogging the 76 engine while it's still in the rusty donor, prior to pulling the engine/tranny/xfer for install into my '66. It's something that I can do now, while waiting on some other parts., and it's too cold and damp for painting. I guess with all this new info, I can go out now and evaluate what to do to keep both rigs running. In phrog's setup, does the fuel just go back for recirculation right back into the same line? That looks pretty simple. I'll check back after I hike up the hill where both rigs are parked and get them down in front of the shop. If there's a plug in the '79 non usa carb,can I just swap fittings on the sides of both carbs and run like that? Easiest yet! My typing on this page as I write is black on black. I can barely see what I am writing, but when I post up, it's normal. Thanks for the help, all

 

[FJ40Jim]

I have tried Phrog's setup before. (Great minds think alike )
It works OK w/ full tank. It stops working when the tank is empty, because the fuel pump suction side is pulling on the Tee fitting, where it can either pick up the fuel from the bottom of the tank, or suck air down through the return line. Sucking air is easier than picking up fuel, so that's what it does.

It seemed like a good idea at the time.

 

[island45]

Good info. At least for today's swap, I have it covered. The '79 non usa carb has a plug in it where the overflow line would go, and vice versa with the '76. It seems if i just swap out the carb fittings, all plumbing will remain as is and I can continue with the tuning and desmogging process on my '76 engine. I will still need to know how best to deal with the fuel returning to the tank when I drop the whole works into the '66.

 

[PhrogsPhorever]

I have tried Phrog's setup before. (Great minds think alike )
It works OK w/ full tank. It stops working when the tank is empty, because the fuel pump suction side is pulling on the Tee fitting, where it can either pick up the fuel from the bottom of the tank, or suck air down through the return line. Sucking air is easier than picking up fuel, so that's what it does.

It seemed like a good idea at the time.

Yeah, I haven't had any issues with that setup yet, granted that configuration was due to being too lazy (no great mind here) to fix the P.O.s modifications for the Weber Carb that I took off.

 

[FJ40Jim]

The '79 non usa carb has a plug in it where the overflow line would go, and vice versa with the '76. It seems if i just swap out the carb fittings, all plumbing will remain as is and I can continue with the tuning and desmogging process on my '76 engine. I will still need to know how best to deal with the fuel returning to the tank when I drop the whole works into the '66.

E-73 tank--->
single feed line--->
E-78 single line pump--->
pump to carb hardline to fit carb--->
any carb (with fuel return port blocked as needed)--->
Combustification!

 

[island45]

Ok, now I'm getting it. I was thinking my '76 fuel pump had a return line out of it. Cant see it that well down below the battery box. So, you are saying that it's ok to run the E-78 pump directly into the '79 aisan with the return port plugged off? Is the pump internally regulated to put out only a couple of lbs of pressure? I would have been done with this swap by now, but got rained/snowed out and was freezin my *** off. Hoping it clears soon and back at it...

 

[FJ40Jim]

Ok, now I'm getting it. I was thinking my '76 fuel pump had a return line out of it.

Nope. Just one line in, one out.

So, you are saying that it's ok to run the E-78 pump directly into the '79 aisan with the return port plugged off?

Yep, that's how it's done on E-73 cruisers.

Is the pump internally regulated to put out only a couple of lbs of pressure?

Not exactly regulated. It's just the nature of the pump that it can only put out 3PSI when deadheaded.

 

[island45]

Thanks! It's done now, except for putting the '76 carb on the '79. I have plugged it's return port. One good thing about working out in the frikken rain on a soaking wet engine is that when I was all done and fired it up, I could see that the majority of the 1/4" brass pipe plugs I just put in were bubbling. Sheesh... I guess I need to order the real toyota plugs that seat into the head.