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I was wondering if I can use my old gas tank for my swap or do I have to use the fuel tank from my donour truck?
thanks
 

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The problem I have found with using gas tanks is that most have a Fill Pipe Restrictor. Basically, the gas filler tube is to small for the diesel nozzel at the fuel station to fit into. They were made that way to make it hard to fill up your gas car with diesel...
 

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The problem I have found with using gas tanks is that most have a Fill Pipe Restrictor. Basically, the gas filler tube is to small for the diesel nozzel at the fuel station to fit into. They were made that way to make it hard to fill up your gas car with diesel...
Partially true today but the original EPA requirement was to prevent someone from putting leaded gasoline into an unleaded gasoline tank. This requirement was never removed by the EPA even after the sale of unleaded gasoline was no longer available at a service station.
 

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Partially true today but the original EPA requirement was to prevent someone from putting leaded gasoline into an unleaded gasoline tank. This requirement was never removed by the EPA even after the sale of unleaded gasoline was no longer available at a service station.
I didn't know that. I learned about it originally from factory Ford repair manuals on my 1990 town car, from my All-Data collection. They had an entry on "Fill Pipe Restrictor".
 

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I was wondering if I can use my old gas tank for my swap or do I have to use the fuel tank from my donour truck?thanks
Some tanks can be used and some can not due to the coating on the metal but not knowing what you have .I would drop and get it cleaned because of old gas gel and the diesel will remove the gel form the bottom of the tank.
 

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Discussion Starter #7
The gas tank is plastic, and someone told me there would be problems with fuel pressure.
 

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Discussion Starter #9
They said that diesels have a higher fuel pressure so it wont work, and do I have to get bigger lines on the tank.
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Diesels don't like any more supply pressure than a carb engine does. You're probably thinking of the injection line pressures, not supply plumbing.

If the tank holds gas it'll hold diesel. If it's nasty, clean it out, if not then don't worry about it.
 

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On Ford trucks, its as simple as changing the filler neck over from the gas style to the diesel style.

There is alot of miss-information out there about "how to make a gas fuel system work after converting it to diesel?" All you need to do on a truck that had a fuel injected gas engine setup is clean out the tank, install a delete "block off" plate where the Cummins lift pump went, install a pressure regulator inline before the Cummins injector pump. The pressure regulator will reduce the in tank pump(s) pressures to the engine, which are usually higher than a Cummins injection pump can handle. My 460 had 35psi at idle and 45psi at load, the 12 valve Cummins injection pump only likes around 15-18psi max inlet pressure. A check valve in the fuel line is also a great idea (optional). A vehicle that is old enough to have a lift (transfer) pump on the gas engine is even simpler, just hook up the lines to the Cummins lift pump.
 

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With pumps in the tanks you don't need a regulator, you can just hook the pressure and return lines together with a small orifice (say 3/32" or so) and tie the engine supply line in before the orifice and the return line in after the orifice. Real simple, nothing to go wrong and the in tank pumps are nice for circulating and heating anything through the tanks like WVO or waste oil.
 

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The gas tank is plastic, and someone told me there would be problems with fuel pressure.

I used the original factory Dodge Dakota plastic tank on my Diesel conversion. In fact I even used the internals to the sending unit with a lot of modifications. Had no problems and running for 2 yrs now
 

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Chevy TBI should be even easier then, their pressure is much lower... God forbid if I can remember what TBI pressure IS though. :idea: I could look it up!

On Ford trucks, its as simple as changing the filler neck over from the gas style to the diesel style.

There is alot of miss-information out there about "how to make a gas fuel system work after converting it to diesel?" All you need to do on a truck that had a fuel injected gas engine setup is clean out the tank, install a delete "block off" plate where the Cummins lift pump went, install a pressure regulator inline before the Cummins injector pump. The pressure regulator will reduce the in tank pump(s) pressures to the engine, which are usually higher than a Cummins injection pump can handle. My 460 had 35psi at idle and 45psi at load, the 12 valve Cummins injection pump only likes around 15-18psi max inlet pressure. A check valve in the fuel line is also a great idea (optional). A vehicle that is old enough to have a lift (transfer) pump on the gas engine is even simpler, just hook up the lines to the Cummins lift pump.
 

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The p7100 pump pressure relief valve opens at 25psi. I dont remember what the rotary pump is though... So anywhere right in there is good. Supposedly my pump pressure is around 40psi from the tank, so A large Racore filter setup should bring it down a little. If not, ill just install a pressure relief valve.
 

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The p-pumps like pressure. The dodge guys add an extra spring to the overflow valve, will be in the 35-40 psi range at idle. Stock, its 20-25 at idle, and 35-40 at 2k rpm.
 

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The p-pumps like pressure. The dodge guys add an extra spring to the overflow valve, will be in the 35-40 psi range at idle. Stock, its 20-25 at idle, and 35-40 at 2k rpm.
Got a link to info on this? Or know what spring people are using?
 

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Get a click pen, take the spring out of it. Take the spring out of the OFV, and cut the pen spring to the same length. Put the two in together. Lots of reading on this on DTR. Other guys will take the stock spring and stretch it out. This is generally a temp fix as the spring will relax back to its original length.
 

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Galvanized fuel tanks

Some tanks can be used and some can not due to the coating on the metal but not knowing what you have .I would drop and get it cleaned because of old gas gel and the diesel will remove the gel form the bottom of the tank.
Scott, you got the right idea! If the old fuel tank is galvanized then the zinc used in the galvanizing process will react with the diesel fuel. You also want to avoid copper or any alloyed metal that contain copper or zinc, this includes fuel lines. Most earlier model gasoline fuel tanks were made of galvanized steel, later they changed to plastic tanks. If you put a coating on the inside of the tank that separates the fuel from the zinc you would probably be alright.Stainless,Plastic,Fiberglass,Black iron, and Aluminum are all OK.
 
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