TR4/4A Fuel Line Fittings - Stock or Upgrade?

Currently getting close to putting the fuel tank and fittings back in our '64 TR4. Wondering what everyone's thoughts are on the best ways to run these. The factory version I believe just used an undersized hose pressed onto tubing, with compression fittings going into the tank and pump. This seems a bit rudimentary to me. I prefer something with a little more "positive" seal for something as crucial as the fuel system.

Has anyone made upgrades to their fuel lines? Open to ideas. I am thinking something like nice braided AN6 fuel hose and fittings from the tank to the pump would be ideal. Has anyone used AN lines on their TR4?

I made my fuel lines from 3/8 od seamless stainless tubing and Swage-lock brand compression fittings to a swagelock Panel mount ball valve that fit nicely in the original shut valve tab bracket.From the valve stainless line bent up almost to fuel pump,then rubber hose to connect to the oringinal metal line and fiitting into the fuel pump,then original line and fittingout of the pump routed as original thru bracket by tstat,then a short piece of hose to the front carb.
I had the luxury of ordering from Mcmaster/Carr thru my employer as extras for a lab project,and used the stock fittings that came in the project boxes for the pump connections.

Tom

I added worm type hose clamps to all the "push on" connections, and used modern ethanol-resistant low pressure fuel line. I do like to use the clamps that are entirely SS (as opposed to the more common ones where only the band is SS).

Not much of an upgrade, but good enough for me. I can't see the need for using high pressure stuff for lines that carry essentially no pressure at all.

MMC will sell to anyone these days. They used to only deal with commercial accounts, but they take credit cards now. Still don't have a "parts counter", you have to order by phone or over the Internet. But if you're near one of their warehouses, you can have your order put in "will call" and save shipping charges. There's also a phone next to the "will call" center, where you can place your order

Thanks for the advice. Very true on the lack of pressure involved here. Just wanted to make sure there was not a simple upgrade available before piecing together the system.

McMaster is fantastic. We have purchased all kinds of bolts and nuts for this project from there. They also carry parts that work for some of the hard to find rubber seals on the car, such as where the air vents meet the plenum. Shipping is crazy fast, especially if you live within 500 miles or so of Chicago.

This is going to be a bit on the long side and includes some sourcing information.

I never upgraded this sort of stuff on the TR4A I had but did make a number of modifications to my TR6, among them going to -6 (3/8") fuel hoses and tubing from the -5 (5/16"). I believe the fittings at the tank and at the fuel pump are the same size on the TR4/4A/250 and carb versions of the TR6. The hose and tubing from the tank to the fuel pipe are -5 while the runs from the fuel pump to the carbs are -4 (1/4"). Threaded connections at the tank and the fuel pump should all be 1/2"-20, which as luck would have it, is the same thread size and pitch as a -5 AN flare fitting. Like TFB, I used -6 stainless tubing for the long sections of the run along the frame along with a few shorter sections of -6 tubing with braided -6 hose and various AN fittings as the flex hoses to get my fuel lines plumbed. Since there were multiple hard line segments with some complicated clocking orientations for my set up, I did an initial hand bent mock up using soft tubing to get a basic feel for the routing, bend radii (tried to stay at a 3d bend radius) and bend tangent points. While it wasn't the same degree of help for making up the long tubing run along the frame, it still came in handy.

Coming off the fuel tank I used an AN919-7D reducing union, -5 on one end and -6 on the other end. On the -5 side of the fitting, the flare portion was removed leaving the 1/2”-20 section that would screw right into the tank. The bore of the fitting on the -5 side was was increased to match the -6 side of the fitting. The areas where the anodized coating was removed from the fitting were given brush coat of MIL-C-5541 chem film. There are short braided hose assemblies coming off the tank and in the boot where my filter and electric fuel pump are located, as well as coming up into the engine compartment to the carbs and between each of the carbs. The fitting was installed into the threaded boss on the fuel tank using a brushable polysulfide sealant.

You will need an adapter at the stock fuel pump as well if using and this is where it gets a bit trickier for me. I do not have a stock fuel pump handy so I don't know if those AN919 fittings would have sufficient clearance to be used. Operating on the assumption that they would fit, you would need another AN919-7D on the inlet side of the pump along with either another AN919-7D on the outlet if you wanted to run -6 toward the carbs or an AN919-3D (-5 to -4 reducing union) if you wanted to run -4 toward the carbs. Again, this is where the -5 side of the union should have the tapered seat area removed and the bore increased on the -5 side on the AN919-7D unions. If you use one of the AN919-3D unions , you do not want to open up the bore on the -4 side since it would impact the sealing surface.

Properly torqued AN type flare fittings should seal up with no problem but if want a little extra insurance, you could use some Del Seals. These are thin 1xxx series (not sure of which specific alloy) "commercially pure" aluminum in an annealed condition that deform on install. They are primarily used on fittings that have been in service and may have scratches or other small defects. When the seal deforms on installation it fills those small imperfections to help ensure a good seal.

Aircraft Spruce has the basic AN fittings at as good or better price than anyone else. They also sell the Del Seals, the chem film under the Alodine trademark and a number of different versions of the polysulfide sealant. I used the 3M AC-350 A-2 that is a Type A (brushable/pourable) with a two hour working life. It meets AMS-S-8802 (formerly MIL-S-8802) requirements.

Other out fits such as Pegasus Racing, Summit, Jegs, etc have the Aeroquip, Earls or similar for the hose fittings and hose. Pegasus generally has the best prices on the hose fittings. I don’t think any of them have Del Seals, chem film or polysulfide sealants. However, Pegasus does seem to the only one I can think of offhand that carries the Stat-O-Seal and Dowty sealing washers. West Marine carries a line of polysulfide sealants that sounds like it would be semi close to the AMS-S-8802 Type B. It’s from Boat Life brand sold as Life Calk. You can probably find it at any reasonable size boat dealer or boating supply as well. It’s single part, so no mixing required. I do know some people that have used it but I have no direct experience with it.

Wow thank you for the fantastic response, Tybalt! Exactly what I was looking for.

The stock fittings are confusing to me. It is almost as if they are an "inverted flare" type fitting (like a brake line), but then they use a ferrule like a compression fitting.

What you are suggesting is that AN dash fittings thread into the stock female threads. I assume this would not seal as-is, so you add polysulfide sealant to finish the job. Is this correct? Is the fit of the cut-off AN union "tight" enough to prevent mechanical loosening from vibration? Or does the sealant prevent leaks as well as prevent movement? Is the sealant essentially the chemical equivalent of welding a fitting permanently to the tank and fuel pump?

Sorry for the million questions. Your solution sounds exactly like what I am looking for. Just want to make sure I am on the same page here.

mweg87 said:

Wow thank you for the fantastic response, Tybalt! Exactly what I was looking for.

The stock fittings are confusing to me. It is almost as if they are an "inverted flare" type fitting (like a brake line), but then they use a ferrule like a compression fitting.

What you are suggesting is that AN dash fittings thread into the stock female threads. I assume this would not seal as-is, so you add polysulfide sealant to finish the job. Is this correct? Yes, that is correct. Is the fit of the cut-off AN union "tight" enough to prevent mechanical loosening from vibration? Probably, but I didn't give it a chance to do so. Or does the sealant prevent leaks as well as prevent movement? The sealant serves multiple purposes. It assists in preventing galvanic corrosion, it provides a fluid seal and the sealant is a pretty good adhesive but still removable. Is the sealant essentially the chemical equivalent of welding a fitting permanently to the tank and fuel pump? It acts as a pretty decent somewhat flexible adhesive, not anything like JB Weld.

Sorry for the million questions. Your solution sounds exactly like what I am looking for. Just want to make sure I am on the same page here.

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Don't worry about the questions they are not a problem, see comments inserted into your post above.

Take a look at things, confirm the threads at the fuel pump and come up with your basic layout as far as where you want hard lines and soft lines, then drop a PM on me and we'll kick it around and complete configuring the plumbing run and discuss the sealant and Alodine in more detail before you go and start rounding stuff up.