Home » Public Forums » GMCnet » IN-TANK FUEL PUMPS
| IN-TANK FUEL PUMPS [message #242473] |
Thu, 06 March 2014 10:33  |
corleyw
Messages: 130
Registered: June 2007
Location: Battle Ground, WA
Karma: 0
|
Senior Member |
|
|
Rob posted this in the nylon fuel lines forum, (but of course it has little or nothing to do with nylon fuel lines), which got me thinking about in-tank fuel pumps, and which would be ideal and why. Please try to keep this on topic, and only discuss "in-tank pumps" as much as possible.
Rob recommends a low pressure in-tank pump (3 psi), and has several reasons to justify that choice. If one is sticking to the Q-jet, that would seem like a pretty good choice. However, if one is contemplating eventually going to EFI, then you may feel a higher pressure pump is in order. GM mid '80s - mid '90s TBI EFI systems as used on a 454 Chevy truck, used a 12 psi in-tank pump. With Rob's suggestion, you would have to add an additional external pump to go to TBI EFI. As I understand it, other EFI systems use even higher pressure pumps, many in the 40 PSI range. Maybe it would make more sense to install a higher pressure pump to start with, then add a regulator as needed to get the proper pressure for the Q-jet, if that was retained? Maybe you feel as Rob does that the lower pressure in the lines is a good thing, or maybe you feel that a higher pressure in the lines would be a better protection against Vapor lock. That's the sort of thing we'd like to know...
For this discussion, let's assume:
1) Two in-tank pumps
2) A return line
3) A Q-jet for now, with possible future upgrade to TBI EFI
4) Price is not much of a factor (but don't recommend a Newmar diesel pusher)
The question then is, what pumps would you install, and why? If you have any specific part numbers, any pictures you can supply, etc., that would also be welcome information. The mechanics of vapor lock have been beat to death, so please try to avoid rehashing all that crap.
I've copied Rob's post here to kick things off. 
Corley
'76 Glenbrook
29 other vehicles
|
|
|
|
| Re: IN-TANK FUEL PUMPS [message #242475 is a reply to message #242473] |
Thu, 06 March 2014 10:40  |
corleyw
Messages: 130
Registered: June 2007
Location: Battle Ground, WA
Karma: 0
|
Senior Member |
|
|
I'm also copying Emory's post on this subject because it is good information on sourcing from one of our venders.
We all need to SUPPORT OUR VENDERS! Without them we have a nice little chicken house with wheels.
| emerystora wrote on Thu, 06 March 2014 05:13 |
Jim Kanomata at Applied GMC has a kit for low pressure fuel pumps for the GMC motorhome.
He carries both the low pressure and the high pressure pumps and kits.
Emery Stora
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
Corley
'76 Glenbrook
29 other vehicles
|
|
|
|
|
|
|
|
| Re: [GMCnet] IN-TANK FUEL PUMPS [message #242538 is a reply to message #242473] |
Thu, 06 March 2014 17:40 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
|
Senior Member |
|
|
Corley,
I have done my level best to word the following response in such a way so as not to offend you or anyone else in any way, shape, or
form. If I did not succeed I apologize in advance.
I am going to intersperse my response in your email in CAPS for clarity, I am not shouting.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Corley Wooldridge
Rob posted this in the nylon fuel lines forum, (but of course it has little or nothing to do with nylon fuel lines),
I RESPONDED TO A QUESTION POSED BY BILL DOLINSKY IN THE "HARD FUEL LINES ONCE AGAIN" THREAD; "DON'T THINK I HAVE EVER SEEN A LOW
PRESSURE IN TANK PUMP BUT HAVE NOT LOOKED." I THINK YOU SHOULD BLAME HIM FOR RAISING THE QUESTION IN THE WRONG THREAD. ;-)
which got me thinking about in-tank fuel pumps, and which would be ideal and why. Please try to keep this on topic, and only discuss
"in-tank pumps" as much as possible.
Rob recommends a low pressure in-tank pump (3 psi),
I DO MY BEST NOT TO "RECOMMEND' ANYTHING ON THIS FORUM. IN FACT I'LL BET IF YOU GO BACK THROUGH MY MESSAGES YOU WON'T FIND ME USING
THE WORD "RECOMMEND" AT ALL. IF I DID IT WAS A MISTAKE TO DO SO! PLEASE RE-READ MY EMAIL AND YOU WILL NOTE I STATED "I HAVE two
Repb314509's so I can run one in each tank." IT WAS NOT MY INTENTION TO RECOMMEND THESE PUMPS AND IF BY PROVIDING THE INFORMATION I
"RECOMMENDED" ANYTHING IT WAS UNINTENTIONAL. ALSO THE (3) PSI PUMP IS THE DELPHI FE0065 IS NOT THE PUMP I AM USING. I MADE A MISTAKE
AND NOTED THAT THE REPB314509 PUTS OUT 6-7 PSI WHICH I CORRECTED IMMEDIATELY IN A FOLLOW UP EMAIL TO 4.0 TO 5.785 PSI.
and has several reasons to justify that choice.
I WAS NOT JUSTIFYING ANYTHING, I MERELY STATED MY REASONS FOR MAKING THAT CHOICE. BY THE WAY DID I STATE ANYTHING INCORRECT?
If one is sticking to the Q-jet that would seem like a pretty good choice.
EXACTLY! I HAVE A PATERSON Q-JET ON DOUBLE TROUBLE AND HAVE NO INTENTION OF GOING TO EFI.
However, if one is contemplating eventually going to EFI, then you may feel a higher pressure pump is in order.
I AGREE THAT IF YOU INTEND TO INSTALL EFI THEN INSTALLING HIGHER PRESSURE PUMPS MAKES SENSE.
GM mid '80s - mid '90s TBI EFI systems as used on a 454 Chevy truck, used a 12 psi in-tank pump. With Rob's suggestion, you would
have to add an additional external pump to go to TBI EFI.
AGREED, THAT WOULD ADD AN ADDITIONAL FAILURE POINT WHICH IS NOT GOOD DESIGN PRACTICE.
As I understand it, other EFI systems use even higher pressure pumps, many in the 40 PSI range.
THAT'S WHY I STATED; "low pressure in the fuel lines going to the surge tank which would reduce the amount of flow if there was a
leak." I JUST REALIZED I SHOULD CLARIFY THAT AND WOULD LIKE TO INSERT THE WORD "LEAKAGE" IN FRONT OF THE WORD "flow" ABOVE.
Maybe it would make more sense to install a higher pressure pump to start with, then add a regulator as needed to get the proper
pressure for the Q-jet, if that was retained?
I'LL RESPOND TO THIS WITH A QUESTION; WHICH WOULD BE MORE LIKELY TO FAIL AND CAUSE A PROBLEM WITH A Q-JET 455; A LOW PRESSURE PUMP
FEEDING A SURGE TANK (NO MOVING PARTS) WITH A FUEL RETURN TO THE FUEL TANKS OR A HIGH PRESSURE PUMP FEEDING A FUEL PRESSURE
REGULATOR WITH A RETURN TO THE FUEL TANKS?
Maybe you feel as Rob does that the lower pressure in the lines is a good thing, or maybe you feel that a higher pressure in the
lines would be a better protection against Vapor lock. That's the sort of thing we'd like to know...
JIMB ADDED A FACET PUMP BETWEEN THE OUTLET OF THE AUX TANK AND THE SELECTOR VALVE IN DOUBLE TROUBLE. WHEN VAPOR LOCK OCCURS I SWITCH
TO AUX AND THE VAPOR LOCK CEASES INSTANTLY. PLEASE COMPARE THE PRESSURE GENERATED BY THIS PUMP IN THE SPECS BELOW TO THE REPB314509
(4.0 - 5.875 PSI). IT IS REASONABLE TO ASSUME THAT IF A PUMP THAT PROVIDES 1.5 - 4.0 PSI TO THE INLET OF MECHANICAL PUMP CORRECTS
VAPOR LOCK WHEN IT OCCURS A PUMP THAT PROVIDES 4.0 - 5.785 PSI WOULD DO THE SAME. HOWEVER, IT IS POSSIBLE THAT BECAUSE THE SURGE
TANK HAS A LINE PLUMBED BACK TO THE FUEL TANKS THE PRESSURE SUPPLIED TO THE INLET OF THE MECHANICAL FUEL PUMP FROM THE SURGE TANK
COULD BE LOWER. THAT MIGHT ALLOW VAPOR LOCK TO OCCUR IN THE LINE BETWEEN THE SURGE TANK AND THE INLET OF THE MECHANICAL FUEL PUMP.
PART #: 40104
MIN - MAX PSI: 1.5 - 4.0
GPH: 25
INLET/OUTLET THREAD SIZE: 1/8-27 NPT
MIN. DRY LIFT: 12"
CHECK VALVE: NO
For this discussion, let's assume:
1) Two in-tank pumps
2) A return line
3) A Q-jet for now, with possible future upgrade to TBI EFI
4) Price is not much of a factor (but don't recommend a Newmar diesel pusher)
The question then is, what pumps would you install, and why? If you have any specific part numbers, any pictures you can supply,
etc., that would also be welcome information.
WHEN I WAS RESEARCHING THIS I DISCOVERED THAT MOST OF THESE PUMPS ARE MADE IN CHINA AND THAT ON VARIOUS FORUMS PEOPLE NOTED THEY
WERE CRAP. I DECIDED TO BUY THEM ANYWAY BECAUSE WHEN I DO THIS JOB I WILL PROVIDE ACCESS TO THE FUEL PICKUPS THROUGH THE FLOOR SO IF
THEY FAIL I CAN REPLACE THEM EASILY. IF THEY FAIL I WILL REPLACE THEM WITH FUEL PUMPS MADE IN THE USA IF I CAN FIND THEM.
HERE'S A LINK TO THE SURGE TANK THAT I USED: http://tinyurl.com/kvrze4a
FULL URL:
http://www.ebay.com.au/itm/Universal-Complete-Fuel-Surge-Tank-2-Litre-Swirl-Pot-System-Aluminium-Surge-tank-/231168521688?pt=AU_Car_
Parts_Accessories&hash=item35d2b7b5d8&_uhb=1
The mechanics of vapor lock have been beat to death, so please try to avoid rehashing all that crap.
I've copied Rob's post here to kick things off. :d
DELETED
Corley
'76 Glenbrook
29 other vehicles
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
|
|
|
|
|
|
|
|
| Re: IN-TANK FUEL PUMPS [message #242941 is a reply to message #242473] |
Mon, 10 March 2014 16:03 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
|
Senior Member |
|
|
I will be using high pressure pumps, most likely walbro in tank. I have had very good luck with these and esp when cooled by fuel, good durability.
Primary reason is I will be eventually run an AirSensors EFI that I already have.
To my mind a return type reg system will work better even with the carb and the higher pressure should help keep the fuel from vaporizing, as will the lower dwell time in the lines.
The air sensor unit has its own bypass reg but an external one would let me reduce the PSI and convert back to the Qjet on the road if need be.
You can also keep your mechanical pump in place with a fuel loop inlet to outlet and a small ammount of kerosene in it to keep it lubed as a backup plan
76 Glenbrook
|
|
|
|
Goto Forum:
Current Time: Fri Oct 04 13:25:56 CDT 2024
Total time taken to generate the page: 0.01335 seconds
|
GMCforum
Search
Help
Register
Login
Home
So what question did I raise? My recollection is that I merely responded to other peoples posts? But I'll take the blame. 
