In tank fuel pumps, or external pumps.

[d c *mac* macdonald]

Belt AND suspenders, eh, Jim?

Mac Macdonald in OKC

Sent from my iPhone

I take the stand that when the in tank pump goes out, the other inline pump
will work.

>
> It is not a problem, IF you are in a shop with a hard floor WHEN the pump
> (s) fail and you need to drop the tanks. Carefully read the submission by
> Glen Gregory about fixing fuel pumps alongside a busy highway while semi's
> blow past at 70 per. Not a very safe way to spend an afternoon.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>

>>
>> A lot of us have "been there" with different ways of plumbing fuel to the
>> engine. IMO, pumps in the tanks and all steel fuel lines is the final
>> answer. Two tanks, two pumps. Both pumps are a back-up for the other.
>> Either will allow you to drain...I'd guess...2/3rd s of the 50gal of fuel
>> you
>> can carry, meaning you can get'r home. JMHO
>>
>> As far as having access holes in the floor of your coach to change the
>> pumps, personally, I would not bother. If you put pumps in the tanks, as
>> outlined in the Stora article, because the assembled tank unit is fairly
>> big, (especially if you change to all steel lines) you need a lot of room
>> around the tank hole to manipulate the assembly when inserting it into
> the
>> tank. You'd have to have quite a large hole in the floor. I have a
> small
>> hole (6" in dia.) to check in case of leaks or electrical issues.
>> Dropping the tanks is not as big of a deal as made out to be. The hardest
>> part of
>> the whole thing is draining of the tanks and where to put all of that
>> fuel. Draining is actually relatively easy. Just hook a section of rubber
>> fuel
>> line to the line at the fuel rails, throttle body or a convenient spot in
>> the fuel lines, and wire the pump to pump the fuel out. I can drop both
>> tanks, fix and replace in a morning. .
>>
>> HTH
>>
>> --
>> Larry
>> 78 Royale w/500 Caddy
>> Menomonie, WI.
>>
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--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
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[Jim Hupy]

Mac, I prefer to do my coach maintenance inside my well lighted and heated
shop, not alongside a 2 lane with trucks ripping by at warp speed. Just me,
I guess.
Jim Hupy

> Belt AND suspenders, eh, Jim?
>
> Mac Macdonald in OKC
>
> Sent from my iPhone
>

>
> I take the stand that when the in tank pump goes out, the other inline pump
> will work.
>
> > On Fri, Apr 21, 2017 at 7:22 AM, James Hupy

> >
> > It is not a problem, IF you are in a shop with a hard floor WHEN the pump
> > (s) fail and you need to drop the tanks. Carefully read the submission by
> > Glen Gregory about fixing fuel pumps alongside a busy highway while
> semi's
> > blow past at 70 per. Not a very safe way to spend an afternoon.
> > Jim Hupy
> > Salem, Or
> > 78 GMC ROYALE 403
> >

> >>
> >> A lot of us have "been there" with different ways of plumbing fuel to
> the
> >> engine. IMO, pumps in the tanks and all steel fuel lines is the final
> >> answer. Two tanks, two pumps. Both pumps are a back-up for the other.
> >> Either will allow you to drain...I'd guess...2/3rd s of the 50gal of
> fuel
> >> you
> >> can carry, meaning you can get'r home. JMHO
> >>
> >> As far as having access holes in the floor of your coach to change the
> >> pumps, personally, I would not bother. If you put pumps in the tanks, as
> >> outlined in the Stora article, because the assembled tank unit is fairly
> >> big, (especially if you change to all steel lines) you need a lot of
> room
> >> around the tank hole to manipulate the assembly when inserting it into
> > the
> >> tank. You'd have to have quite a large hole in the floor. I have a
> > small
> >> hole (6" in dia.) to check in case of leaks or electrical issues.
> >> Dropping the tanks is not as big of a deal as made out to be. The
> hardest
> >> part of
> >> the whole thing is draining of the tanks and where to put all of that
> >> fuel. Draining is actually relatively easy. Just hook a section of
> rubber
> >> fuel
> >> line to the line at the fuel rails, throttle body or a convenient spot
> in
> >> the fuel lines, and wire the pump to pump the fuel out. I can drop both
> >> tanks, fix and replace in a morning. .
> >>
> >> HTH
> >>
> >> --
> >> Larry
> >> 78 Royale w/500 Caddy
> >> Menomonie, WI.
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[chris tyler]

> How about using a cheap ethanol / gasoline separator. (I have never seen one.) That would bring the RVP back to what we had before this EPA
> madness. With the separator you could dump the excess ethanol in the exhaust just like the thermosan units, or you could mix it with water and put
> it in the black tank for later disposal.
>
> We have guys at the airport doing this separation with water but it is a standalone operation. We have never found a use for the removed ethanol
> and water mixture, so it just gets dumped. I'm sure the EPA is not happy about that but they are the ones who caused the problem in the first
> place.

I dont know of any practical way to remove ETOH from gasoline since they are miscable. Water and gasonine are not, so they easily separate and
stratify via surface tension and density.
In esoteric theory, I suppose you could heat it and the ETOH would vaporize first, but a number of the lighter elements in gassoline would as well.

The main advantages for in tank pumps is they run cooler, are quieter and protected more from damage at the cost of inaccessibility . particularly
important for fuel injection and High pressure. I cant think of any OEM FI using external pump, but someone on here may.

That being said, if you are running carbed, I still think the Carter external as a booster with the mech pump is the way to go

--
76 Glenbrook

 

[LarryW]

> It is not a problem, IF you are in a shop with a hard floor WHEN the pump
> (s) fail and you need to drop the tanks. Carefully read the submission by
> Glen Gregory about fixing fuel pumps alongside a busy highway while semi's
> blow past at 70 per. Not a very safe way to spend an afternoon.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403

Oh, I read Glen's submission and fully agree with his assessment. That scene can be avoided with two tanks, two pumps. If one fails,, the dash
switch puts you to the other tank/pump, and allows you to get to a safe place to work on it. The real issue is vapor lock, a condition that (in
addition to other upgrades) can be significantly reduced by placing the pumps in the tanks. But then....it's just my relatively informed, off the
cuff, back yard mechanic, gut level, eyeball it up and guestimate, opinion....that's all...
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.

 

[emerystora]

Chris
Actually, you can easily do it by just adding water to the gasoline. It will absorb the ethanol and then you can separate the water from the gasoline.
It is not very practicable for large amounts such as a motorhome tankful but some have done it for motorcycles and lawnmowers.
Here is an example:

http://goldwingdocs.com/forum/viewtopic.php?t=14679

One problem is that it will also leach out other additives which are useful in gasoline.
Also, removing the ethanol will reduce the Octane so you can end up with very low octane gasoline which might ping a lot.

Emery Stora
77 Kingsley
Frederick, CO

>

>> How about using a cheap ethanol / gasoline separator. (I have never seen one.) That would bring the RVP back to what we had before this EPA
>> madness. With the separator you could dump the excess ethanol in the exhaust just like the thermosan units, or you could mix it with water and put
>> it in the black tank for later disposal.
>>
>> We have guys at the airport doing this separation with water but it is a standalone operation. We have never found a use for the removed ethanol
>> and water mixture, so it just gets dumped. I'm sure the EPA is not happy about that but they are the ones who caused the problem in the first
>> place.
>
>
> I dont know of any practical way to remove ETOH from gasoline since they are miscable. Water and gasonine are not, so they easily separate and
> stratify via surface tension and density.
> In esoteric theory, I suppose you could heat it and the ETOH would vaporize first, but a number of the lighter elements in gassoline would as well.
>
>
> The main advantages for in tank pumps is they run cooler, are quieter and protected more from damage at the cost of inaccessibility . particularly
> important for fuel injection and High pressure. I cant think of any OEM FI using external pump, but someone on here may.
>
> That being said, if you are running carbed, I still think the Carter external as a booster with the mech pump is the way to go
>
> --
> 76 Glenbrook
>

 

[a.]

> ...I just don't see how moving the pumps just outside the tanks can help reduce vapor lock to any measureable degree. That 115 degree gas might
> hit the external pumps at 118 degrees. That's along way from vapor lock temps. I don't see in tank pump as a bad idea. I just would like to find a
> reason to justify the extra work for me. Bob Dunahugh
Its simple Bob. Outside the tank requires enough suction to raise it some PLUS overcome the resistance to flow over the distance from the in-tank
pickup to the pump.

For a pump at the bottom inside of the tank, that rise and length is zero. That difference in "negative" pressure can easily mean the difference
between vaporizing a component of the fuel at the pump inlet and NOT vaporizing it.

I don't know if anyone has numbers. But like I keep saying, if an in-tank pump cavitates, the universe has aligned to stop your progress. Get as
comfortable as you can, and wait for the temperature of the fuel at the inlet to the pump to drop low enough to not vaporize/cavitate.

You might never see it with external pumps. You pays your money and you takes your chances. But remember, if the engine won't run, the Onan probably
won't either. No dash AC and no roof AC while you wait for sundown.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"When I grow up I am going to be a curmudgeon."

 

[kerry pinkerton]

The advantage to two pumps imo is that if one fails, the other will get you to a safe place so you can work on it. I've been down lots of roads where
there was no safe place to pull off so that's important to me.

I commented earlier about not going below 1/2 tank. IF I was concerned about vapor lock, I'd get gas at the half tank level just to keep putting
cooler fuel in the tank. Not to mention, I'll want to pee every couple hundred miles anyway.
--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L

 

[robert mueller]

Chris,

Along with being miscible it's miserable and I wish it was miss-able!



Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Chris
Tyler
Sent: Friday, April 21, 2017 1:10 PM
To: gmclist
Subject: Re: [GMCnet] In tank fuel pumps, or external pumps.

I dont know of any practical way to remove ETOH from gasoline since they are
miscable. Water and gasonine are not, so they easily separate and
stratify via surface tension and density.
In esoteric theory, I suppose you could heat it and the ETOH would vaporize
first, but a number of the lighter elements in gassoline would as well.

The main advantages for in tank pumps is they run cooler, are quieter and
protected more from damage at the cost of inaccessibility . particularly
important for fuel injection and High pressure. I cant think of any OEM FI
using external pump, but someone on here may.

That being said, if you are running carbed, I still think the Carter
external as a booster with the mech pump is the way to go

--
76 Glenbrook

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