800 passenger tank line

[michaelp]

I'm about to install the passenger-side gas tank in my 800B. Has anyone ever used the nylon hose, like the stuff originally used on the Scout II's? I found this at mcmaster:

mcmaster-carr

It seems like this would be easier to route and set up for the long run from the passenger tank to the tank selector switch than metal, and I understand it's pretty durable. Anything wrong with this approach?

Also, I have the super Scout filler neck with the vent hose - do people just route this back into the tank compartment, or do you put anything on the end to deal with vapors or potential fuel escape for overflow/rollover?

 

[Michael Mayben]

Fuel-contact rated nylon tubing has been used in the evaporative emissions systems since 1967 by all domestic oem manufacturers, both for vapor contact and for liquid contact. If the stuff is "fuel-rated" then it is suitable for carrying liquid gasoline. And even with old, oem stuff, I've found no issues so far regarding deterioration due to contact with ethanol-laced fuels (e10).

For vapor transmission, it is acceptable to insert the nylon tube into appropriate rubber fuel hose and use a clamp to secure. I would never do that for liquid fuel transmission!!!

The problem in dealing with the nylon tubing is connection/termination. The stuff uses it's one particular type for both brass transition fittings and for the actual connection which is a form of compression fitting. IH used that type fitting on the fullsize rigs in order to feed the dual tank mechanical selector valve on some vehicles (not all). A full service auto supply carries the proper compression nuts and nylon compression ferrules for work with this type tubing, you do not use "similar" types of terminal fittings used with abs/pvc/pex semi-rigid tubing used in household water plumbing!!!! Nor do you use any type fitting designed to work with common copper tubing with "compression" fittings.

It also requires the insertion of a small tubular brass "insert" in the prepared end to allow the nylon compression ferrule to seal without collapsing the tubing material.

So unless you have a good assortment of proper terminations and the proper diameter tubing (all ihc liquid fuel plumbing is 5/16" tube), it's going to be a real problem to work with! And it still must be supported along it's run with proper hangers, same as with steel or rubber tube.

It's also used in several colors. That was for identification of liquid and vapor lines used in automotive evaporative emissions systems which can be rather complicated. Common colors sued were black, red, blue, white, yellow, and green.

Personally, I do not use the stuff except when making a proper repair on evaporative emissions systems plumbing if need be.

 

[michaelp]

That makes sense. Ideally I'd like to do that run from the passenger tank with as few couplers as possible. I found some 25' rolls of metal fuel line including this one:

amazon.com: omix-ada 16737.82 universal steel fuel line 5/16in x .028in coil with 10 fittings (25 ft): automotive

And one from sur&r, which I verified could also be used for fuel:

s.u.r. & r. Brez300 5/16" brake line tubing, 25'

The sur&r stuff is pretty expensive, but I understand it's hand-bendable, and very easily routable. Whaddya think of these options?

 

[Michael Mayben]

I use plain old 5/16" brake tubing in the 25' roll from the local parts house. Easily bent/radiused with any of the inexpensive chinee hand benders.

But first...look at the size of the fittings on each tank, I believe you will find those to be 1/4", unless those were transitioned to 5/16" for the v8 engine app in the s800. Those fitting determine what size tubing to use or you will have to make up a transition fitting.

Also look at the fittings on the tank selector valve, after verifying that the valve itself is in good condition and does not leak. If it leaks, then it's an easily replaced item available in any auto supply also that carries typical brass fuel plumbing components/fittings. Since you have access to a carquest there, they should have a cabinet stocked with this kinda stuff, I buy prolly $100 a month worth of brass fittings and pre-terminated brake tubing from my local carquest every month. The plumbing ports on the valve itself are 1/4" npt so they can accept either 1/4" flare or 5/16" flare adapters in all port positions. The selector valve is nothing special, a simple part that was used on all oem applications that had multiple tanks, a very common industrial item.

From the selector valve to the fuel pump you can run 5/16" and then on to the carb. Though I never use steel out of the fuel pump, I always run it in soft hose through the filter(s).

Do not ever use copper tubing for fuel plumbing, that is not acceptable even though dimensionally it's the same as steel and the flare fittings are the same pattern.

Pic here is a new valve made up with the soft hose plumbing for one of my s80 rigs (same tank setup as yours). This one has three inlets, one of 'em is plugged.