Dual feed holley lines...leaking.
Thread Starter
Burning Brakes
Joined: Jul 2006
Posts: 833
Likes: 4
From: Mexico NY
Dual feed holley lines...leaking.
I've completed the vac sec 750 install on my 383 and it fired up.. I had to shut her down because the fuel line were leaking like heck. how do you guys seal them? how tight do I tighten them? I'd hate to ruin anything but need to get a seal to continue tuning and drive (I hope some day) up here in Central NY.
Drifting
Joined: Apr 2008
Posts: 1,540
Likes: 51
From: Lexington Park Maryland
I've had a dual feed "Holley" chrome line on my small block w/750 Holley for close to 20 years without a problem. I've even had them off a few times to change Power Valves and Jets. Is your dual feed line a "Holley" or a different brand ??
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
The true Holley fuel lines used a flare fitting and should not need teflon tape. The threads do no sealing at all, they just pull the flare in tight. Now I do not know if your fittings have been changed or not and they might be different types of threads.
I should say the ones used on the LT1 carbs, there are many different types of fittings for a Holley. Find out what you have on both the fuel line and carb and see if they match.
I should say the ones used on the LT1 carbs, there are many different types of fittings for a Holley. Find out what you have on both the fuel line and carb and see if they match.
Last edited by Gordonm; Mar 26, 2009 at 04:45 PM.
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
You have to crank down the feed line nut...1" open end wrench to tighten the carb fitting, make sure there is a metal gasket between the car and the fitting...next use the 1" open end to keep the fitting from moving and use a 5/8" line wrench to tighten the nut....you should be fine.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
This response show a basic MISUNDERSTANDING of how SAE inverted flare fittings work. Teflon tape is NOT required to seal a SAE fuel line. The seal in a SAE system is done at the flare junction of the tube and the fitting seat not between the fitting threads like in a NPT pipe thread system. You should first make sure the fittings on the float bowl have the thin gaskets on them, then make sure they are TIGHT but be careful of stripping your Holley's fuel bowls. Then put a little anti-sieze between the flare nut and tube and some on the flare nut threads. Using TWO wrenches, a 1" for the float bowl fittings and a inverted flare wrench for the chrome fuel line, tighten the nuts into the fittings by working one wrench against the other. You may have had the misfortune to have cracked the solder joint in the chrome fuel line if you twisted the tubing too far (especially if it is one of the cheap junk ones made in China.) Teflon tpe has no place in afuel system and if not applied properly, can founl the fuel system with particles. I have "fixed" many cars by cleaning the fuel systems of teflon tape that had fouled the needle and seat of a float needle because of sloppy craftsmanship while being assembled.
Pro
Joined: Feb 2005
Posts: 627
Likes: 5
From: Frisco TX
Pro
Joined: Mar 2008
Posts: 716
Likes: 1
From: Albuquerque New Mexico
I'm not a fan of the spectre stuff at auto zone if that's what you have. My opinion is that it's worht it to buy a decent dual feed setup for $50 - $100 for such an imporant piece. The way these fittings are designed to work, I would think that teflon tape is only going to make it more difficult to get a good compressed seal on the flares. I'm just not seeing how teflon will help.
One little trick I found works well on the dual feed lines that use alumium fittings is to put some saran wrap around the nuts before you tighten them and keeps the wrench tighter and also doesn't gouge or scratch the hardware.
One little trick I found works well on the dual feed lines that use alumium fittings is to put some saran wrap around the nuts before you tighten them and keeps the wrench tighter and also doesn't gouge or scratch the hardware.
[/IMG]
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
That was/is a nice closeup of your lines. You even went one step further than I did as your use of a flare 'T' where I was just lazy and used a compression 'T'. One 20 inch 3/8 line and tubing bender and your all done at the carb end....
advantage, NO leaks and under $10
advantage, NO leaks and under $10
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
I agree with the make your own, and that the flares, if done properly and of sound structure SHOULD seal it. But were talking about possible fuel leaking on a hot surface here. I still use teflon tape as a precaution and always have. It adds an extra level of protection, ....and adds no risk!?
Drifting
Joined: Apr 2008
Posts: 1,540
Likes: 51
From: Lexington Park Maryland
You have to crank down the feed line nut...1" open end wrench to tighten the carb fitting, make sure there is a metal gasket between the car and the fitting...next use the 1" open end to keep the fitting from moving and use a 5/8" line wrench to tighten the nut....you should be fine.
This is a very important point I forgot to mention. Yes....., it's a two wrench process to tighten properly. Also......, I've never put "tape" on the dual feed line fittings. Never leaked without it either.
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
I agree with the make your own, and that the flares, if done properly and of sound structure SHOULD seal it. But were talking about possible fuel leaking on a hot surface here. I still use teflon tape as a precaution and always have. It adds an extra level of protection, ....and adds no risk!?
Really shouldn't use teflon tape on a fuel line..
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
can you expound on this opinion? I admit to being a total amateur when it some to this stuff but have been a tinkering fool for years....like I said have always been advised to use teflon tape and always have...and never had any problems... other posters here seem to agree with using it. You and Solid LT1 seem to be adamantly against it...so could you help us understand why you think it's BAD?
TIA
TIA