Home » Public Forums » GMCnet » Hard fuel lines once again
| Hard fuel lines once again [message #242176] |
Mon, 03 March 2014 12:54  |
corleyw
Messages: 130
Registered: June 2007
Location: Battle Ground, WA
Karma: 0
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Senior Member |
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It's time that I must pull the tanks, so I am going to install the hard lines off the tank, move the feeder line outside the frame, and all that stuff at the same time. A friend has suggested using nylon(?) lines instead of steel lines, as all new cars use.
His reasoning is that: a) all the newer cars use nylon lines, and they are impervious to all the brews and concoctions that the mfgrs of fuels might come up with. b) They do not absorb heat as rapidly as does steel, so are less likely to contribute to vapor lock. c) They are somewhat flexible, making it easier to route them. d) They are fairly cheap, e) even the fittings are pretty cheap as it turns out. f) Since the new car manufacturers use them in todays hot engine compartments, with proper anchoring, they should be safe. g) No rubber lines are needed to absorb engine vibrations and flex. h) They can handle EFI fuel pressures, whereas some rubber lines cannot. j) Quick disconnect fittings are readily available for nylon lines. k) With nylon lines, fuel has less restrictions to flow, since they are an end to end solution, with no restrictive or turbulence causing fittings along the way.
These types of lines have been very difficult for the average guy to work with in the past, and the tool to install the fittings is expensive (~$100). Here is an alternative to that tool, and more information about them.
http://www.nastyz28.com/forum/showthread.php?t=220894
I have not yet made a decision on whether I'll use steel lines or these nylon lines, and I'm leaning toward sticking to the steel lines. I'm just starting my research. However, it's something to think about, as some of the arguments for them are quite compelling.
I wanted to ask Emory's opinion since he has done the hard line change, but he does not accept PMs. Hopefully he will see this and respond with his thoughts.
Corley
'76 Glenbrook
29 other vehicles
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| Re: Hard fuel lines once again [message #242182 is a reply to message #242176] |
Mon, 03 March 2014 13:40  |
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Richard RV
Messages: 631
Registered: July 2012
Location: Full-timer for 12 years, ...
Karma: -17
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For all the reasons you mention I'm surprised that nobody is selling a nylon fuel line kit for the GMC. There's definitely a market, and the only barrier that I can see is a not-so-expensive expensive tool for the fittings.
That caulking gun nylon fitting "tool" is mighty sketchy. It would be better to buy the real tool used on eBay and sell it on eBay when you're done. That makes for a very cheap rental.
Richard
'77 Birchaven TZE...777;
'76 Palm Beach under construction;
‘76 Edgemont waiting its turn
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| Re: Hard fuel lines once again [message #242188 is a reply to message #242176] |
Mon, 03 March 2014 14:41 |
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wally
Messages: 643
Registered: August 2004
Location: Omaha Nebraska
Karma: 5
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Senior Member |
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Not Emory but I used Dorman nylon line with these unions to adapt steel tube stubs on the tanks/senders to the nylon.
http://www.dormanproducts.com/itemdetail.aspx?ProductID=18543&SEName=800-135
These unions are made for the purpose and have the nylon tube inserts built in to the union kind of like air brake DOT fittings. Amazon had the best price on them. No need to buy the line tool to use these unions.
JWID
| corleyw wrote on Mon, 03 March 2014 12:54 |
It's time that I must pull the tanks, so I am going to install the hard lines off the tank, move the feeder line outside the frame, and all that stuff at the same time. A friend has suggested using nylon(?) lines instead of steel lines, as all new cars use.
His reasoning is that: a) all the newer cars use nylon lines, and they are impervious to all the brews and concoctions that the mfgrs of fuels might come up with. b) They do not absorb heat as rapidly as does steel, so are less likely to contribute to vapor lock. c) They are somewhat flexible, making it easier to route them. d) They are fairly cheap, e) even the fittings are pretty cheap as it turns out. f) Since the new car manufacturers use them in todays hot engine compartments, with proper anchoring, they should be safe. g) No rubber lines are needed to absorb engine vibrations and flex. h) They can handle EFI fuel pressures, whereas some rubber lines cannot. j) Quick disconnect fittings are readily available for nylon lines. k) With nylon lines, fuel has less restrictions to flow, since they are an end to end solution, with no restrictive or turbulence causing fittings along the way.
These types of lines have been very difficult for the average guy to work with in the past, and the tool to install the fittings is expensive (~$100). Here is an alternative to that tool, and more information about them.
http://www.nastyz28.com/forum/showthread.php?t=220894
I have not yet made a decision on whether I'll use steel lines or these nylon lines, and I'm leaning toward sticking to the steel lines. I'm just starting my research. However, it's something to think about, as some of the arguments for them are quite compelling.
I wanted to ask Emory's opinion since he has done the hard line change, but he does not accept PMs. Hopefully he will see this and respond with his thoughts.
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Wally Anderson
Omaha NE
75 Glenbrook
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| Re: [GMCnet] Hard fuel lines once again [message #242190 is a reply to message #242185] |
Mon, 03 March 2014 14:48 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Sigmond, If the tanks are empty or nearly so, it isn't that much of a
hassle to drop them. In all probability, the rubber elbow and sleeve that
connects the filler pipe to the tanks will be as deteriorated as the fuel
lines are. You will want to inspect them carefully anyway, and once you
have those hose clamps off, you are at least half way home. It is sure a
lot easier to remove the senders with the tanks out. The "O" ring seals on
the senders are another place that leaks fuel and smells up the coach. All
the metal line fittings are easier to work on with the tank resting on saw
horses as well. But I am not saying that it cannot be done with the tanks
in place, it can be. Lastly, do not forget the vent lines to the
liquid/vapor separator and filler neck. They can often be pinched between
the body and frame if the isolator bumpers are bad. (They often are either
bad or missing). Good luck with your project whichever way you decide to go.
Jim Hupy
Salem, Or
78 GMC Royale 403
On Mar 3, 2014 12:23 PM, "Sigmund Frankenfelter" <ziggy.frankenf@gmail.com>
wrote:
>
>
> I have been considering the replacement issue. I have already drilled two
> holes in my floor to get to my sending units ( by the way, at least in my
> 78 Royale, the measurements suggested are off a few inches)
>
> Since I don't have a working gas gauge for either tank, I effectively
> can't run them dry and drop them. It has to be from the top. I am thinking
> steel and compression fittings, as appears to be the most secure method
> I've seen so far. Once I get my sending units out and working, I'd like to
> go with steel.
>
> You know what would be cool? A bending diagram, where you match the bend
> to the paper. Also, it would be helpful if guidance was received from
> someone who had replaced the lines without dropping the tanks. Can it be
> done? What fittings would be best?
>
> I am sure this has already been tackled by someone.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
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| Re: [GMCnet] Hard fuel lines once again [message #242192 is a reply to message #242191] |
Mon, 03 March 2014 14:56 |
Mr ERFisher
Messages: 7117
Registered: August 2005
Karma: 2
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or here
http://gmcws.org/blog/wp-content/uploads/2012/09/In-tank-Fuel-Pump-seminar.pdf
On Mon, Mar 3, 2014 at 12:55 PM, gene Fisher <mr.erfisher@gmail.com> wrote:
> here is the poop on hard lines
> http://gmc49ers.blogspot.com/2013/12/good-news-for-gmc-ers.html
>
> gene
>
>
>
> On Mon, Mar 3, 2014 at 11:05 AM, Espen Heitmann <bimet@online.no> wrote:
>
>>
>>
>> There is one safety issue with them.. they melt, I have a buddy doing
>> some welding and one small glow went straight thru one of the lines from
>> the fuel tank.
>>
>> Pretty scary, we used several fire extinguishers to stop that car from
>> burning and it happend really fast.
>> --
>> 1973 26' Parrot green Seqouia in Norway
>> "Loffen" translates to white bread, it is also a nick name for your..
>> well you know..down there.. and it was my dog's name, but hey you can also
>> call me Espen ;)
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> "Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://gmcmotorhome.info/
> Alternator Protection Cable
> http://gmcmotorhome.info/APC.html
>
--
Gene Fisher -- 74-23,77PB/ore/ca
"Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] Hard fuel lines once again [message #242211 is a reply to message #242207] |
Mon, 03 March 2014 17:22 |
kelvin
Messages: 608
Registered: February 2004
Location: Eugene, OR
Karma: 0
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On 3/3/2014 3:09 PM, Sigmund Frankenfelter wrote:
>
> It looks like I will first have to get my fuel sensors working, then run the tanks down to empty, or close, then drop the tanks to install the hard lines.
>
> Whew! That's a production.
Get the tanks drained as far as you dare. Buy a cheap electric fuel
pump, disconnect the fuel line on the left side of the engine (before it
heads over to the mechanical pump) and plumb the electric pump into
that. Drain the tanks into 5 gallon fuel cans. It might take a couple
of them.
You can lower the tanks with a little fuel in them. Doesn't make much
difference since they're just plain ungainly no matter how you do it.
That's how I've done it... three times.
You would think once would have done it, but no, there were mistakes
made twice. :-)
Kelvin
'73 23' in Eugene, OR
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| Re: [GMCnet] Hard fuel lines once again [message #242214 is a reply to message #242185] |
Mon, 03 March 2014 17:45 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Sigmund,
I can't see how you could replace the lines without dropping the tanks, besides it's a good idea to inspect the inside of the tank.
I would suggest you consider:
Poly Armour Tubing 3/8" OD:
http://www.autozone.com/autozone/accessories/AGS-Poly-Armour-Brake-line-Located-in-backroom-fixture/_/N-268g?itemIdentifier=602044_0
_0_
Poly Armour Tubing 5/16 OD:
http://www.autozone.com/autozone/accessories/AGS-Poly-Armour-Brake-line-Located-in-backroom-fixture/_/N-268g?itemIdentifier=602043_0
_0_
Swagelok Fittings:
http://www.swagelok.com/downloads/webcatalogs/EN/ms-01-140.pdf
You can cut the beads off the fuel pickup on the sending units and fit Swagelok fittings.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Sigmund Frankenfelter
I have been considering the replacement issue. I have already drilled two holes in my floor to get to my sending units ( by the
way, at least in my 78 Royale, the measurements suggested are off a few inches)
Since I don't have a working gas gauge for either tank, I effectively can't run them dry and drop them. It has to be from the top. I
am thinking steel and compression fittings, as appears to be the most secure method I've seen so far. Once I get my sending units
out and working, I'd like to go with steel.
You know what would be cool? A bending diagram, where you match the bend to the paper. Also, it would be helpful if guidance was
received from someone who had replaced the lines without dropping the tanks. Can it be done? What fittings would be best?
I am sure this has already been tackled by someone.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] Hard fuel lines once again [message #242224 is a reply to message #242219] |
Mon, 03 March 2014 18:47 |
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Richard RV
Messages: 631
Registered: July 2012
Location: Full-timer for 12 years, ...
Karma: -17
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| Loffen wrote on Mon, 03 March 2014 17:14 |
Hi
Nylon lines will never come on my car for sure, that fire did scare me big time..
|
What would scare me is welding near fuel lines, period. So...no welding while driving!
Richard
'77 Birchaven TZE...777;
'76 Palm Beach under construction;
‘76 Edgemont waiting its turn
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| Re: Hard fuel lines once again [message #242231 is a reply to message #242176] |
Mon, 03 March 2014 20:54 |
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SeanKidd
Messages: 747
Registered: June 2012
Location: Northern Neck Virginia
Karma: 4
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Senior Member |
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I'm going cunifer (copper-nickel-ferrous) with all brass fittings, double flare...and dual carter p4070, all the way to the carb...and back, vapor and individual vents to the fill. All metal, no steel except for the pick up tube. No socks, custom #30 mesh strainers.
Except for my fill system...I have a Type-1 with the metal tee at the aux tank...unfortunately I will have 5 fill hose and clamp connections.
That is if it ever warms up.
Sean and Stephanie
73 Ex-CanyonLands 26' #317 "Oliver"
Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms, P.Huber TBs, 3.70:1 LSD Honda 6500 inverter gen.
Colonial Travelers
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| Re: Hard fuel lines once again [message #242238 is a reply to message #242207] |
Mon, 03 March 2014 21:49 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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| Francois wrote on Mon, 03 March 2014 16:09 |
It looks like I will first have to get my fuel sensors working, then run the tanks down to empty, or close, then drop the tanks to install the hard lines.
Whew! That's a production.
|
A big production, yes, but not really that difficult.
http://www.gmcmhphotos.com/photos/g5520-gas-tank-fuel-line-project-6-10.html
Other than not following the prevalent opinion that all hard lines should be used, you might find this helpful.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Hard fuel lines once again [message #242239 is a reply to message #242214] |
Mon, 03 March 2014 21:57 |
corleyw
Messages: 130
Registered: June 2007
Location: Battle Ground, WA
Karma: 0
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Senior Member |
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| USAussie wrote on Mon, 03 March 2014 14:45 |
Sigmund,
I can't see how you could replace the lines without dropping the tanks, besides it's a good idea to inspect the inside of the tank.
I would suggest you consider:
Poly Armour Tubing 3/8" OD:
http://www.autozone.com/autozone/accessories/AGS-Poly-Armour-Brake-line-Located-in-backroom-fixture/_/N-268g?itemIdentifier=602044_0
_0_
Poly Armour Tubing 5/16 OD:
http://www.autozone.com/autozone/accessories/AGS-Poly-Armour-Brake-line-Located-in-backroom-fixture/_/N-268g?itemIdentifier=602043_0
_0_
Swagelok Fittings:
http://www.swagelok.com/downloads/webcatalogs/EN/ms-01-140.pdf
You can cut the beads off the fuel pickup on the sending units and fit Swagelok fittings.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Sigmund Frankenfelter
I have been considering the replacement issue. I have already drilled two holes in my floor to get to my sending units ( by the
way, at least in my 78 Royale, the measurements suggested are off a few inches)
Since I don't have a working gas gauge for either tank, I effectively can't run them dry and drop them. It has to be from the top. I
am thinking steel and compression fittings, as appears to be the most secure method I've seen so far. Once I get my sending units
out and working, I'd like to go with steel.
You know what would be cool? A bending diagram, where you match the bend to the paper. Also, it would be helpful if guidance was
received from someone who had replaced the lines without dropping the tanks. Can it be done? What fittings would be best?
I am sure this has already been tackled by someone.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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That poly armor tubing looks pretty neat, but I am not sure why you need the 'special' fittings, won't regular feral fittings work with that tubing? Or, does the armor cause issues with normal fittings???
The thing that I like about the poly armor is that it has a layer of insulating material on it, albeit a very thin layer.
Corley
'76 Glenbrook
29 other vehicles
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| Re: Hard fuel lines once again [message #242240 is a reply to message #242222] |
Mon, 03 March 2014 22:00 |
corleyw
Messages: 130
Registered: June 2007
Location: Battle Ground, WA
Karma: 0
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Senior Member |
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| Larry wrote on Mon, 03 March 2014 15:44 |
| wally wrote on Mon, 03 March 2014 14:41 |
Not Emory but I used Dorman nylon line with these unions to adapt steel tube stubs on the tanks/senders to the nylon.
http://www.dormanproducts.com/itemdetail.aspx?ProductID=18543&SEName=800-135
These unions are made for the purpose and have the nylon tube inserts built in to the union kind of like air brake DOT fittings. Amazon had the best price on them. No need to buy the line tool to use these unions.
JWID
|
So, I take it that the Dorman nylon line is impervious to alcohol? If so, why haven't we been using this instead of the other options like Gates Barrier rubber hose? What is it's burst rate?
|
The nylon line is indeed alcohol safe. It's what is used on most new cars now days. It has a pretty high melt/flash point, but it will burn. So will rubber lines. So will plastic fuel filters.
Corley
'76 Glenbrook
29 other vehicles
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| Re: [GMCnet] Hard fuel lines once again [message #242244 is a reply to message #242239] |
Mon, 03 March 2014 23:35 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Corley,
You can use any kind of flareless fitting you like with the Poly Armour tubing.
The reason I specified Swagelok was because those were the fittings I used most often when building ground support test equipment
for Project Apollo at the Johnson Spacecraft center.
Click on this link http://tinyurl.com/ns83cms and note numbers 80 and 82.
As you can see they have two ferrules which grip and seal the tube in two places whereas normal flareless fittings have a single
ferrule. I found the two ferrule Swagelok fittings were less prone to leaking after multiple installations and removals.
I would not use a Swagelok to Swagelok union where the lined join the fuel pickup; I would use a Swagelok to an AN 37 degree flared
fitting because a flared fitting can stand multiple installations and removals no problem.
Swagelok fittings are available in brass and stainless steel.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Corley Wooldridge
That poly armor tubing looks pretty neat, but I am not sure why you need the 'special' fittings, won't regular feral fittings work
with that tubing? Or, does the armor cause issues with normal fittings???
The thing that I like about the poly armor is that it has a layer of insulating material on it, albeit a very thin layer.
Corley
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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