Drilling into diesel tank while full?

[Tellie]

You really haven't given enough information. There are a few issues that may arise by attempting to drill into a diesel tank. First the ignition should not be a problem. I've accidentally drilled into two SS diesel fuel tanks before, not that I recommend it. Secondly, where in the tank where you going to drill? I assume from your post that it will be from the top since the tank is full of fuel. Diesel lines are from the top with a pickup tube going down to the bottom of the tank internally which would mean you will need acess to the inside of a full tank to attach the pick up tube. Thirdly, especially in a plastic tank I would highly discourage drilling a hole in or near the bottom of the tank. This would be a great spot for potential fuel leakage and all the trouble that comes with. Fourth, drilling a plastic tank and tapping a few threads works well for plastic water tanks but diesel fuel would be harder to properly seal. The best method would be plastic welding a fitting to the drilled hole. But as Goboatingnow states if you are using the ebespacher standpipe fitting it will make this job easier.

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[goboatingnow]

Tellie, the Op needs to only use the ebspacher standpipe, you CANT really use anything else unless its exactly the same diameter. The standpipe is included in the standard marine parts that are supplied with the kit

The instructions are clear , drill from the top of the tank. you don't need any internal access.

plastic or SS it doesn't matter, Ive done both.

dave

[zboss]

I T'd my dickinson diesel heater into the fuel line going to the engine about 700 engine hours ago. Have not had a problem and we have run the diesel and the heater at the same time.

If you are paranoid, insert a stop-cock.

[ssanzone]

If you have space for a 2nd tank, I would install one and then T into the deck fill line so you fill both tanks at the same time.

While at it, plumb a 2nd line from the heater tank and T it into the existing tank to engine fuel line (with in line ball valves) so you can:

1. reduce the risk of running out of diesel while motoring
2. bypass the main fuel tank in the event of leaks etc
3. introduce feasibility of service / maintenance without compromising functionality

-steve

[goboatingnow]

Originally Posted by ssanzone

If you have space for a 2nd tank, I would install one and then T into the deck fill line so you fill both tanks at the same time.

While at it, plumb a 2nd line from the heater tank and T it into the existing tank to engine fuel line (with in line ball valves) so you can:

1. reduce the risk of running out of diesel while motoring
2. bypass the main fuel tank in the event of leaks etc
3. introduce feasibility of service / maintenance without compromising functionality

-steve

with respect

I think the OP just wants to fit a standard eberspacher standpipe to his tank, not replumb the whole fuelling system

lets not overthink the solution, its simple enough

[stevensuf]

Yes i have the standar eiberspacher stand pipe which does not require internal tan k access to fit and picks up from the bottom of the tank and is designed to be fitted from the top, t-ing would be much simpler, but i did this with a watermaker and heads and was not the best idea i ever had.

The system has its own fuel pump now i cant remember if it has to be fitted below or aboev tank level.

[wgewaldii]

Originally Posted by stevensuf

...how safe would be drilling into the PLASTIC tank while full of diesel? I know diesel i quite difficult to ignite, IE throw a match on it and it goes out. I am concernes of any vapours/fumes etc

My welding instructor repaired a metal tank filled with diesel fuel. Apparently he thought it was no big deal. He did have an assistant stand by with a fire extinguisher.

[minaret]

Originally Posted by wgewaldii

My welding instructor repaired a metal tank filled with diesel fuel. Apparently he thought it was no big deal. He did have an assistant stand by with a fire extinguisher.

Very foolish. We fill tanks with an inert gas (usually Argon) before cutting or welding, even after cleaning. Safety first.


http://en.m.wikipedia.org/wiki/Argon

[capngeo]

LOL, being I live in a temperate climate, I read the title and was thinking why would he want to heat his fuel? Then in a flashback to my youth, I remembered a stinky-sooty, hot thing on the bulkhead of my uncle's boat. LOL!

[Jim Cate]

Originally Posted by minaret

Very foolish. We fill tanks with an inert gas (usually Argon) before cutting or welding, even after cleaning. Safety first.


Argon - Wikipedia, the free encyclopedia

Minaret, I've watched pro welders arc welding on steel diesel tanks when full of fuel. I was apprehensive to say the least, but they explained that welding below the fuel level was not risky... the diesel acted as a coolant, there was essentially no oxygen at the weld site and "what could possibly go wrong?". I was still worried, but they went ahead, paying no attention to the nervous WAFI. I could hear fuel boiling away in the tank, but they were right: nothing happened. I dunno if this is a great recommendation of the practice!

In the case of "empty" tanks, the argon is a very good idea IMO, for in that case there can be plenty of oxygen present and no cooling. Have you ever used CO2 instead of Ar? Often easier to source away from civilization.

Cheers,

Jim

[Cheechako]

To answer your original question, I would have no problem drilling into a plastic diesel tank.

[hpeer]

Originally Posted by goboatingnow

with respect

I think the OP just wants to fit a standard eberspacher standpipe to his tank, not replumb the whole fuelling system

lets not overthink the solution, its simple enough

Quite right.

FWIW I drilled my main tank, 3/16" steel, with diesel. I used lots of cutting fluid, went slow.

Not recommending, just relating.

[W3GAC]

I've installed several diesel heaters. DO NOT TAP INTO THE MAIN ENGINE FUEL LINE. Three reasons: 1) Air sucks easier than diesel... any breach/ leak in the heater fuel line/ filter line in the future will shut down your engine/ require that you find the air leak, fix it, and bleed the engine fuel line/ system before you'll be able to restart the main. Do you really want to add this unnecessary risk during a storm/ harbor entrance? 2) The typical small piston fuel pumps for diesel heaters are not very strong and can't lift a typical 3/8" fuel line column of diesel very far. Most diesel heater fuel lines are very very small (about the size of a plastic ballpoint pin refill) for that reason and warnings about not tapping/ using regular fuel line are all over the instructions/ warnings. 3). Anytime the main engine is running (especially if your engine has a return line to the tank) it creates a suction on the supple fuel line tap. The weaker heater fuel pump will not only have to overcome the weight of the larger column of the main line but also the negative suction pressure of the main fuel pump pulling fuel up from the tank.




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[rwidman]

Originally Posted by goboatingnow

with respect

I think the OP just wants to fit a standard eberspacher standpipe to his tank, not replumb the whole fuelling system

lets not overthink the solution, its simple enough

Well in that case, if he had bothered to mention this fact, this would have been a much shorter and to the point thread.

If you want the right answers you have to ask the right questions.

[Shawn67]

"3). Anytime the main engine is running (especially if your engine has a return line to the tank) it creates a suction on the supple fuel line tap. The weaker heater fuel pump will not only have to overcome the weight of the larger column of the main line but also the negative suction pressure of the main fuel pump pulling fuel up from the tank."

What about T-ing into the return line? That is assuming the return has a stand pipe on it. If not then you would starve the heater pump of fuel if the engine wasn't running and the tank level was below the exit of the return.

Shawn