Combined fuel feed/return

[Nanko]

Combined fuel feed/return

[coachgeo]

Now that's some fine craftsmanship.

Now please tell me why creating such compactness is needed to dictate using a method like that?

Are you conscrned that movment will cause the two to rub together inside that joint and cause a leak? Once you know it's leak free maybe fill it with expoxy??

[Nanko]

With this device you dont have to drill a second hole in your tank.
Injector fuel leak ( spill?) connection is connected to the coppertube

[coachgeo]

ahhh so the left side of the top photo sticks into the tank?

[Nanko]

Yes

[Sphere]

That's a very nice piece of craftmanship

[Dan J]

I really like it Nanko. Does it screw into the normal Enfield fuel tank?

Don't fancy making another do you?!

[Diesel Dave]

That's the neatest return I've ever seen.

Is that a pice of Kunifer brake pipe?

Epoxies or Silver Solder?

Dave

[Nanko]

4 mm copper pipe , silver soldered

[coachgeo]

my understanding is copper like that will work harden leaving the tendency to crack. Just something to keep an eye on.

[andrewaust]

Agreed! Great little set up, well though out Nanko



A

[Dougy]

Heres a pic of the tap where using on our diesal bike, I had high hopes for it at first as a feed / return but having taken it apart theres no hope for it being used as a return , on the original fuel tank off the Yanmar the fuel return goes to the top of the tank, and before I spotted this thread I was thinking about doing something similar, but now....I see the return here goes virtually no further than the bottom of the tank, so my question- is there no problem having the return flow coverd by fuel ?

[Dan J]

Dougy, on my Enfield I've recently redone the fuel pipework but the principal is the same... I have a "t-piece" below the fuel tank tap but before the filter and this is fed by the fuel return line - so anything that does get returned gets refiltered. I ensured the pipe was full of diesel when I put it all together to ensure there was no airlock etc.

[Dougy]

Thanks Dan, I've asked a few people about this return feed buisness now and have got a few differant answers, some have said what you said, plumb the return into a tee piece in the fuel line, others have said dont do that as the fuel going around in a loop can overheat and damage the pump, I really wanted to fit the return on the right side underneath the tank but theres some doubt if you can return the diesal underneath the surface (on the pics here you cant actually see how long the return pipe is), I've also been told by a mechanic that on bikes with dry sumps the oil is always deliverd back to the surface of the tank, maybe theres a good engineering reason for this ? But this is how Yanmar do it,so I may do that in the end but the debate goes on so I'll keep watching for replys on this for a bit as I've got a few other jobs to do first.

[Darren]

T-ing in the pipe will not damage the pump due to overheat.

I know lots of people that have done this to run on vegetable oil. Sometimes they run diesel in these vehicles without problems.

I've run cars with big fuel heaters on diesel fuel for extended periods (a year plus). The fuel would have been very hot all the time. Even done this in a car with a computer controlled injection pump.

I've never heard of a injection pump being damaged by overheated fuel.

I've heard it said, a fair few times, that the fuel cools the pump. I'm not completely sure where this information comes from.

The main reason for sending fuel back to tank is to expel air (If you T in close to the tap air may well still rise up into the tank). Also best not to T in where the back side of the injectors would be under pressure as it would effect the injector performance a bit.

[Diesel Dave]

Be careful you don't accidentally provide a fuel supply that bypasses the filter.....................................

Easily done, that's why all return lines feed to the top of the tank and drip down.

[Darren]

Yes, good save Dave.

It would depend a bit what engine / injection pump set up you have. Some return lines are always pressurised (eg. Bosch rotary pump) but not all are. I guess that a one way valve could be used to stop possible filter bypass via a return line that was Td into the fuel line feed.

[Eddy Wane]

The petcock mod by Nanko is a simple effective solution. It seems relatively easy to add a mesh filter. My only addition would be to add a length of tube to allow the excess fuel to dribble, pour or cascade into the space at the top of the tank near the filler.

[Sphere]

I can personally recommend you order one from Nanko, it works amazing on my Hatz.