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Should it be copper for conductivity-sake? Also, should it go right TO the bottom or should it hover about a 1/2" or so (I know diesels have issues with dredging tanks).
Hi, I am not sure why it should conduct. I will be making a new pickup for mine and I am just going to get 10mm or preferably 12mm stainless tube and get it tigged to a flange . I will attach it via 12mm 90' compression fitting to nylon fuel line. I would got to the bottom of tank but notch it slightly so it can't get blocked if it sucked on the bottom of the tank.

Gaza
 

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Right, the main reason to keep the return line all the way to the bottom, as specified in the Cummins Shop manual is to;

Keep it from areateong /foaming when returning fuel to less than a full tank. Keep the pickup far as possible from the return and you should not have problems, you dont want to pickup fuel that has air bubbles in it/foam from the return line

Paul
Thanks for this info Paul. This is all new to me. When I install my new pickup I will use my old pick up as the return as the one thats there now only goes in about 1" so will be aerating when it falls into tank.
I have clear lines and when looking with a light behind them the flow to the pump appears stationary as it is clear where as the return appears to have something in it and can be seen moving, at a fair old lick I might add even just ticking over. This I assumed must be air (what else could it be) and I thought I must have an air leak but failed to stop it even though I replace all copper washers in the system. I have now concluded that it must be aerated in the pump, but how? and where does the air come from?

Gaza
 

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Diesel fuel that appears "clear" and "solid" will actually have about 10% air dissolved in it. When you put it through the violence and pressure changes of the pump and injectors (because some of that return fuel is bleed from the injectors), then the dissolved air basically gets "jarred" into forming bubbles in the fuel.
Thanks, I hope the diesel I buy at the pump isn't 10% air.
This then must mean that the diesel being injected must be 10% air aswell.

Gaza
 
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