Fuel Cell Plumbing Questions

don-f

don-f

Well-known member
I am redoing the fuel lines on my project (1970s Civic GTC now being converted to a vintage car). The car actually came to me with a stock fuel tank, one of the many safety hazards on the car when it arrived. I have an ATL 8 gallon fuel cell, but what's the best way to plumb it to the pump? I had it in another car that I used for parts for this project and the two fuel pickups where connected with a T fitting and an old Holley pump was sucking fuel for a foot or so after that. They recommend gravity feeding those Holley pumps, not drawing the fuel out of the top of the cell so not sure about durability. I did have to fuss with the pump a few times. I can put it back the same way, but really I am unsure. On another car, I have seen two micro pumps put right on the top of the fuel cell and then the T fitting. While still not gravity feed, it chops the distance to the fuel pump by about 2/3s. The 1.2L engines are low powered, nothing over 140hp for sure, so not a huge fuel requirement.
 
Today, we use a single pump and a Holley HydraMat.

https://www.youtube.com/watch?v=yfE1v65fNZI

If you really want to get every drop and run the cell dry, fit a lift pump (low pressure pump from the cell to a small make-up tank, run the overflow from the makeup tank back to the cell. With a fitting on the bottom of the make-up tank, you can run direct to your high or low fuel pressure pump to feed the engine.
 
Thank you for the reply. Very interesting I had never heard of that! I am not too worried about running dry as much as I was not sure about the plumbing the fuel cell or the Holley pump as it didn't seem reliable. I have spent the evening snooping other peoples small bore vintage projects online and it seems to vary between either a Holley pump or a few different Facet pumps. The one thing I don't see is anyone running two pickups into one pump like my cell was plumbed. When both pickups are used it looks like everyone uses dual pumps or they just use one pickup and a single pump and cap the other outlet. I like the mat idea, thank you.
 
Don:

After my fuel pump quit in a race at Road Atlanta, I installed two pumps with each having it's own pickup. The pickups are located at opposite ends of the fuel cell. Each pump is separately switched. The pumps sit about three inches above the top of the cell. There is a fuel pressure gauge mounted on the dashboard.I have run at least eight seasons with no problems.

John
 
Thank you for the reply, it helps. That's probably what I will do also as the Holley pumps had a few problems in the past. They are easy to fix but getting towed is no fun.
 
I have a 3-pump setup in my RX7 like what you've mentioned.. Two pickups at each corner of the cell on separate pumps. --> swirl tank --> "main" pump feeding the line going to the engine bay.
top of the swirl tank has a return line that dumps back into the top of the cell to purge any air.

I can run this thing until there's less than ounces in the system. anything the pumps can pick up, they slurp into the swirl tank, and the main pump feeds the engine from the bottom of that tank.


I'm using the old school Carter pumps. Good and bad is that they're ridiculously loud, and each one sounds just a little different. You can hear them all fire up and I can tell by the sound if one of them isn't running.

In ~8 yrs, I've had one or two of these guys "fail" on me, basically when they sat for most of a year and didn't move. then they wouldn't fire back up. I bought replacements and got back to racing, but then someone else told me a trick. disassemble the thing and stick a rubber hose on the end of the motor shaft. stick it in your drill and spin for a while, then reassemble. The brushes/ commutator in the motor quit making electrical contact due to corrosion when they sit for a while. spinning them with the drill cleans them up and they make contact again. voila.
 
Don:

I run the same thing as John. Two Holley red pumps with separate pickups in the fuel cell. But both of my pumps are on the same switch. Then use a fuel regulator to get the pressure right at the carbs. I can send a picture if that would be helpful.

Rick
 
Thank you for the replies. It helps! I have two Holley red pumps, so I will just rebuild those and run them on both outlets.
 
You must log in or register to reply here.
Back
Top