Hey guys, I just competed a sbc 350 swap and it has been running great for a month or so. Today I pulled up to the gas station than started smelling gas!! I took my air cleaner off and saw that gas was blowing straight trough my carb with way to much pressure. Which means my new pressure reg failed. As I don’t have a return line and it was under constant load. Has anyone put a return line in a tj tank? I assume if I just use the vapor line it will vapor lock or blow up. Do I drill a hole on top of the sending unit? Had anyone done this before?
Fuel return
- Thread starter Bdutton11
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- jeep tj sbc
Thought I had better pics than this, but hopefully it helps. I did this for an LS swap into my J10 truck, but I'm using a factory TJ tank and pump assembly, except I replaced the factory pressure regulator with a solid machined piece that just adapts the pressure line to an AN fitting at the top.
I just used a bulkhead AN fitting, comes with two plastic washers to seal both sides. I carefully drilled a hole through the brittle plastic assembly off to the side of the pump with the a flat surface for the sealing washers on both sides, you're going to want a hole saw or rotobroach for this part, a drill bit will have a tendency to grab when breaking through and probably crack the plastic.
The factory pressure regulator is designed to dump the extra fuel straight down back into the reservoir around the pump. This keeps the reservoir full, uses all the gas in the tank and cools the pump. Drilling the hole to the side will make the returning fuel miss the resi. I was worried about the pump not getting enough gas around it to stay cool. When installing the pump assembly it's spring loaded and collapses going into the tank, I mocked it up and measured the metal resi would be at when it's be installed. I drilled a home in the metal resi then installed an angled fitting, forget if it's 30* or 45*, on the in tank side of my bulk head fitting to redirect the returning fuel through the hole and back into the resi. Not sure if it works yet as the truck isn't running, but I don't expect any problems.
I have a friend with this same setup minus the angled fitting on the bulkhead. I'm pretty sure most of his returning fuel misses the resi and just goes in the tank. He hasn't had any problems yet, but it's just a wheeling rig and my truck is going to be a DD, so I didn't want to take the chance.
This may not answer your question because I don't have any experience on an SBC 350 swap for a TJ, but the handful of t-bucket builds I did always had a return line - not for fuel pressure, but for a better & more constant fuel flow that helped to stave off vapor lock (mind you this was FL so it was always hot as fuck). I always ran a mechanical fuel pump that was tailored to the pressure requirement (on the Edels I liked to use I think it was around 4.75 psi) so I never ran a regulator.
Out of curiosity, what are you using for a fuel pump?