BioDiesel Injector return hose

[FrankJack]

Does anyone have a recomendation for buying 1/8" ID hose used on the injectors of a 6.2 or 6.5. I would like to use Bio-Diesel and am told that the standard hose won't hold up.

[ 10-25-2005, 11:53 AM: Message edited by: FrankJack ]

[gavio]

Yes, the stock return lines will definitely melt with Bio-D usage - you don't need to ask how I know......

I had one return line kit melt and start leaking in just a couple weeks!

I've had good luck with Viton tubing purchased from McMaster-Carr www.mcmaster.com (http://www.mcmaster.com)
It takes a bit to navigate their catalog, but once you find it, they ship super fast. I finally found that what worked was the metric sized tubing that measures a teensy bit tight on the injector fittings (I think it turned out to be 4mm, but I may not be remembering correctly - double check your fittings). Be sure to get the "firm" style rather than the hard style. The hard will crack when you stretch it over the fittings (if you want to investigate, McMaster gives you all the specs for the tubing), but the firm has a LOT of stretch to it and will hold tight without breaking.

Mine has lasted for two-plus years now and when I took it apart recently, the hoses all seemed good enough to reuse.

The price is high per foot, but you don't need much.

Good luck!

[FrankJack]

Thanks for the lead. I found the page online and it appears to be what you were talking about. What about the little block offs on both ends. Do they need to be Viton also?

[gavio]

You better believe it! And also the hoses from the front injectors to the main metal return line at the front of the engine. All in all it's a few feet of Viton (like 5 feet, maybe).

Please double-check that size and measure for total length before you order, though, 'cuz my memory may be faulty.....

Good luck!

[Subzilla]

May be a simple answer for a simple question but I'll ask anyway. Do they have the block-offs made up in Viton or does one have to put a clamp or something on one end?

[mhagie]

What concentration are we referring to that destroys the return lines B10,B20 or what?
All bio around here is soy based is that as bad on the lines.
Merle

[gavio]

I have never seen viton caps suitable for use on these injectors. The end caps in the original lines that were on my van when I got it consisted of a metal plug stuck in the end of a short piece of hose, so all I did was put the plug in a new piece of viton. Unfortunately, in one of my earlier experiments (with the harder viton that cracked), one of the plugs blew out and I lost it :( .....so I just screwed in a tight fitting, fine thread screw and all has been well - the plug on the other side is still holding fine, too. smile.gif

I don't know at what concentration Bio-D starts to be rough on rubber, but I have never heard of it being a problem at B20. I have been running concentrations between B100 and B50 and this is in my startup tank, so it's sitting in there for long periods - the straight veggie oil used when operating is much less solvent.

As far as I know, all Biodiesel will behave pretty much the same - the problem isn't with acidity or it being caustic (it's actually neither) it's because it's a strong solvent - so be careful to wipe it off your paint or driveway right away if you spill it.

Good luck!

[arveetek]

From all my research, I understand that B20 poses no threat to old fuel lines and existing rubber hoses. That's why it's the most commonly sold mixture at commercial stations. I would think that anything up to B50 would probably work. Over 50% mix, though, will probably start weakening the lines and hoses. I'm hoping that my current B80 mix doesn't eat my hoses out in short order, but I know I will have to upgrade the hoses eventually.

Casey

[gavio]

Most folks I've encountered in the years I've been doing veggie fuels find that even B100 doesn't cause any problems instantaneously - it usually takes time for leaks to develop unless youy have some rubber parts that are just about to give up the ghost anyhow.

The return lines are kind of an exception - I must say though, that the original lines on my van when I got it did NOT start leaking immediately, it was the new replacements I put on that gave out within a couple weeks.

Anyway, it's just something to watch - you'll know when you start having trouble!