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Building Safer Fuel Lines For Your Muscle Car Or Hot Rod

Hose It Down

Jeff Smith Jun 27, 2017
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“Do you smell gas?”

That’s never a good question to ask. Because the next sound might just be that distinctive whooompff that always accompanies the start of a fire. Nobody likes fire. Fire is bad.

The other day, a buddy was about to start his big-block Chevelle after the car had been stored for several years. With the experience that comes with age, he thought it best to toggle the electric fuel pump first and check for leaks before he started the engine. It only took a few moments to realize that his braided steel fuel line had deteriorated and quickly resembled a drip irrigation system rather than a leak-free fuel hose. What’s scary is the leak was positioned just above the passenger-side exhaust header.

It’s a common ailment that gets very little attention. Pump gasoline has undergone a major evolution in the last 20 years and its reformulation includes a government-mandated addition of 10 percent ethanol that everyone blames for the degradation of fuel lines. But we’ve run across some information that indicates that it is really other nasty additives in the fuel that are causing these problems. But regardless of the real culprit, the results are that rubber fuel lines are deteriorating at an alarming rate. This is one reason why the OE’s long ago abandoned rubber fuel lines.

Accelerating this rubber hose aging process is the time-honored process of only occasionally driving your car. With daily driven vehicles, this problem seems to occur less frequently because the fuel line remains wetted. But on hot rods that are driven infrequently, the fuel line experiences multiple cycles of wetting and drying. After a few cycles, it doesn’t take long for the line to fail.

The difficulty lies in diagnosing a potential problem. There’s no way to visually check the condition of a braided steel, rubber-lined hose. It may look perfect on the outside yet be horribly cracked and failed on the inside. A quick check is what we call the “crinkle test.” If you grab a hose and flex it and you can hear a crinkly sound, the hose is dried up and junk. The hose must, however, be dry for this test to be valid. Wet hoses don’t make the crinkly sound. Of course, this is just a quickie test and certainly not 100 percent reliable. We’ve unfortunately discovered hoses that can pass the crinkle test and still spew like a lawn sprinkler. The only valid test is a pressure test. We’ll show you how to make your own simple AN hose pressure tester.

There are several solutions available to the conscientious car builder—some less expensive than others. The best solution is a material called PTFE. That stands for polytetrafluoroethylene—a plastic material that is best known as Teflon in one specific variation. This material is impervious to the degenerative effects of fuel that also creates a vapor barrier so fuel vapors cannot leak past. One problem with PTFE style hoses is that it is susceptible to kinking due to the plastic’s inelastic nature.

Holley has recently come up with a convoluted design PTFE hose called UltraPro that is very light and also drastically improves the bend radius, making it a much easier material to route. Like all PTFE hoses, Holley’s convoluted hose requires its own specific hose ends and assembly procedure. As you might expect, the hose and fittings are more expensive than rubber-lined braided hose. But the advantage is a very long life span. So if your machine is on its way to becoming a family heirloom, a PTFE hose is a wise investment.

Holley has also come up with a less expensive rubber hose called Vapor Guard, intended for either carbureted or EFI applications. As its name implies, this hose prevents vapor loss, which is less important on carbureted engines, but still viable for EFI engines. This hose uses a much simpler-to-install slip-on barb style hose end that is stupid easy to install.

Finally, along the lines of hoses and fittings, Holley has also introduced a simple steam fitting kit for LS engines that is downright cool. You can buy a complete kit or the individual components to create a personalized version.

We thought we’d run through a couple of different installations to show you how easy it is to create and assemble these different hose packages. None of these hoses will make more horsepower or make you irresistible to the opposite sex. But the choice of PTFE hose might just prevent your car from burning to the ground.

It’s the little things in life that can make the biggest differences.

Bulding Safer Leak Proof Fuel Lines 001 2/14

1. We decided to upgrade this big-block Chevelle with a couple of lengths of Earl’s UltraPro hose to remedy a leaking fuel line hazard.

Bulding Safer Leak Proof Fuel Lines 002 3/14

2. This is a rubber-lined braided hose on a friend’s Chevelle that has obviously failed. That’s not water; that’s 91 octane hydrocarbons bubbling out of a hose that sits directly above his passenger-side header. You only get one guess as to how quickly this would have burned his car to the ground.

Bulding Safer Leak Proof Fuel Lines 003 4/14

3. The UltraPro hose is quite different from rubber hose. Starting with the fittings, Earl’s uses 2024-T8 aluminum and black anodizes the finish (1, 2, 3). The first O-ring (4) allows the fitting to swivel once tightened while the second (5) is a special fluoroelastomer seal that is impervious to all fuels. The ferrule (6) creates the seal between the PTFE hose liner (7) and the outer covering (8). The convoluted design allows for a very tight bend radius.

Bulding Safer Leak Proof Fuel Lines 004 5/14

4. Earl’s recommends wrapping the hose in Teflon tape and using a sharp razor cutter to perform 90 percent of the cut, finishing with a pair of sharp scissors. Next, slide the two sockets over the braid in this fashion. Be sure to retain the white tape over the hose so it doesn’t unravel.

Bulding Safer Leak Proof Fuel Lines 005 6/14

5. Next, twist the olive in between outer braid and the hose. We managed to do this by hand but it might be tough on smaller fittings. Allow a short portion of the hose to extend through the olive and trim it flush with a razor knife.

Bulding Safer Leak Proof Fuel Lines 006 7/14

6. The hardest part for us was starting the threads into the socket. Do this by hand or you might damage the threads. We placed the hose socket in an AN vise holder that allowed us to push harder on the socket to get the threads started. With the threads fully started, we finished tightening with an AN wrench. This takes some effort but it’s not difficult.

Bulding Safer Leak Proof Fuel Lines 007 8/14

7. With our hose ends installed, it bolts up just like any AN fitting.

Bulding Safer Leak Proof Fuel Lines 008 9/14

8. The absolute best test is to pressurize the hose. We drilled these fittings and sealed Schrader valves in place to allow us to pressurize the hose and then dunk the package in water to see if it bubbles. A small amount of air may initially escape from between the fitting and the hose. Or, just pressurize the hose and let it sit overnight. If it still has pressure in the morning, you know the seal is good. Here, the pressure is still 50 psi after an hour on the bench.

Bulding Safer Leak Proof Fuel Lines 009 10/14

9. Holley also makes a cool steam fitting kit for LS engines that is simple to install and looks good.

Bulding Safer Leak Proof Fuel Lines 010 11/14

10. Here’s our functional but fugly steam hose setup on our LS Chevelle. It was in desperate need of visual assistance but was still functional.

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11. This is the dual outlet swivel fitting that works in concert with a single outlet for the opposite side. Note the sealing O-rings. You can purchase these swivel fittings separately to make your own package. Two single outlets could also be used with a -4 AN tee fitting.

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12. Here’s our completed setup on an LS engine returning to the water pump.

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13. We don’t pretend to build pretty stuff, but pro car builder Scott Sullivan knows how. Here’s what he did with polished stainless hard line on an LS3 he’s building.

Parts List
Description PN Source
Earl’s 3/8” Vapor Guard hose, 20 ft. 762066ERL Summit Racing
Earl’s straight -6 AN hose end, 3/8” barb 750166ERL Summit Racing
Earl’s 90-deg. -6 AN, 3/8” barb 759166ERL Summit Racing
Earl’s 45-deg. -6 AN, 3/8” barb 754166ERL Summit Racing
Earl’s -6 UltraPro convo PTFE hose, 20 ft. 682006ERL Summit Racing
Earl’s straight -6 AN UltraPro hose end 620106ERL Summit Racing
Earl’s 90-deg. -6 AN UltraPro hose end 629106ERL Summit Racing
Earl’s 45-deg. -6 AN UltraPro hose end 624606ERL Summit Racing
Earl’s -6 AN UltraPro replacement olive 629063ERL Summit Racing
Earl’s LS steam kit 26-550 Summit Racing
Earl’s -4 AN single outlet (pr.) LS9804ERL Summit Racing
Earl’s -4 AN dual outlet (pr.) LS9805ERL Summit Racing
Earl’s -4 AN one single, one dual outlet LS9806ERL Summit Racing
Earl’s -4 AN Tee fitting AT982404ERL Summit Racing
Earl’s -4 AN 90-deg. 1/8” pipe to -4 male AT982204ERL Summit Racing
Earl’s -4 AN tube nuts (pr.) AT581804ERL Summit Racing
Earl’s -4 AN tube sleeves (pr.) AT581904ERL Summit Racing
Earl’s AN pressure test kit D016ERL Summit Racing
Earl’s vise jaw liner 1004ERL Summit Racing

Photos: Jeff Smith

Sources

Summit Racing
Akron, OH
800-230-3030
http://www.summitracing.com
Holley Performance Products/Earl’s
866-464-6553
holley.com/brands/earls

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