340 LPH in tank fuel pump upgrade w/ 3/8 nylon lines modifications-
1. Pump mounting
2. Pump outlet fitings
3. Return fittings
4. Fuel lines (feed & return) and filter
a. Pump mounting
Quantum fuel pump #QFS-324FT
, about $80
Insulated stainless clamp, McMaster.com #11355T72
, about $5
1x 5/16 x 3" stainless "button head" bolt with SS washers and brass/nylon locknut (Boltdepot.com or McMaster)
2x 5/16 x 1" stainless bolts with brass/nylon lohttps://www.dakota-durango.com/forum/images/editor/menupop.gifcknuts (clamp to angle)
1x 3/4" stainless angle (McMaster #1321T19
, 6", cut to length), about $5
1x 3/4" OD x 5/16 ID nylon spacer (McMaster #94639A865
, bag of 10, use the others for your next project such as spacing your GM PCM!), about $10
b. Pressure fittings at tank
1-3/8 OD nylon rod (Amazon)
3/8 pipe x 5/16 barb brass adapter (eBay, see below for cost, I used a 1/4 NPT here since I already had one, it is best if you can find a single barb fitting)
5/16" nylon flex (accordion) hose (eBay)
3/8 NPT "street" elbow (eBay or your hardware store)
3/8 NPT x 3/8 quick-connect fuel fitting (Amazon)
2x small stainless hose clamps for flex hose (normal 5/16 fuel injection clamps are too big)
c. Return fittings at tank
1/2 ID Viton sealing washers (Mcmaster.com, about $5)
1/4 pipe brass "street" elbow (eBay)
1/4 female pipe x 5/16 barb brass adapter (eBay, all 3 brass fittings were about $16 shipped)
5/16" flex fuel hose (use 2 if you want to extend the return line inside the tank)
5/16" x 12" OD brass or stainless tubing (eBay)
2-3x small stainless hose clamps
d. Fuel lines (pressure & return) and filter
(using QC fittings, can substitute AN hose if desired, will need to adapt fittings as required)
25' nylon fuel line, Dorman #800-072
, about $35
5x 3/8 QC fittings for above, 4x Dorman 800-082 and 2x 800-086 (2x 800-086 90 degree at tank, 2x 800-082 straight at filter, and 1x 800-082 straight at engine bay), about $45
1x 5/16 QC fitting at fuel rail return line, Dorman 800-084
The QC fittings will vary based upon which system is used. The above all fit into 3/8 nylon line.
1x fuel filter, I used Professional Products #10302
(1/2 pipe in/out on AN12 o-ring ends), the C5 Corvette filter would work here as well and it contains an internal regulator. (eBay, about $30 on clearance, YMMV)
2x Russell #6
44020 , 3/8 QC to 3/8 o-ring boss (eBay, about $20 shipped)
1x 1/2 pipe brass male (at filter) to female pipe check valve @ filter inlet- helps to keep pressure for faster starts when engine is warm. (eBay, about $9 shipped)
1x 6410-12-06 #12
SAE/ORB Male x #6
SAE/ORB Female, filter outlet used w/ above Russell fitting (Discount Hydraulic Hose.com about $14
1x 6405-06-08 #6
SAE/ORB Male x 1/2" NPTF Female used with above Russell fitting (Discount Hydraulic Hose.com, about $7)
Bracket & hardware as required to mount filter, usually a 2x2 aluminum angle works well
Adapters as needed for fuel rail (pending)
(Optional) Fiberglass insulation for supply line and 1/2 or 5/8 split loom for insulation and physical protection of nylon line.
Pint of POR-15 fuel tank sealer (Amazon), used to treat steel & aluminum parts that are in contact with contaminated fuel
Hylomar sealant, used under Viton washers
Teflon tape for pipe threads
The brass and stainless parts will stand up to fuel that has been contaminated by Ethanol via taxpayer subsidies.
Main performance issues here are the supply line is tiny- like 1/4", and the system is a returnless one that dumps excess fuel at the top of the tank, which aerates it. Aerated fuel can cause problems for pumps, so my design will place returned fuel under the tank fuel level to minimize or eliminate aeration.
1. Pump mounting
(completed; see attached PDF):
The Durango uses an in-tank pump and has "Quick Connect" QC) fittings. Drop the tank and remove the pump/sender assembly by rotating the retaining plate/lock ring. To get at the pump, you have to use a couple of screwdrivers and pry the upper part from the lower part. The next problem is the upper part of the lower housing that retains the pump. I used some small screwdrivers to depress the tabs in the small mounting hole and worked it free. The old pump, in my case a Walbro, can then be removed. Save the wiring, as the Quantum pump uses the same connector.
I looked this over & while there is a replacement Walbro setup that looks like it would be a better fit, the pump is not as good and it costs a lot more. After doing some research, I came up with the idea of using an insulated clamp to hold the pump in place via a bolt from the bottom of the housing. The clamp I found has a SS bracket and a TBR rubber insulator that is chemical resistant. See the attached PDF for more details.
To mount it, I drilled out the bottom of the housing to 1.25". This allowed for a snug fit on the pump, and use of a low-profile "button head" bolt allowed the strainer to clear. The 1.5" clamp holds the pump with foam sleeve well and should help insulate it further from noise. I used a piece of 3/4 SS angle to attach to the clamp, and then a 5/16 x 3" bolt from the bottom of the housing. The flex hose will connect to the modified regulator once that part is complete. You can discard the top part that held the pump in place by disconnecting the sender wires or by cutting the plastic. If removing wires, make sure they go back into the same spots.
After calculating maximum amps over distance, I'm running a 10 gauge feed wire back to the pump and will replace the terminal at the pump connector that is on top of the tank (pending).
After the final install, I noticed the larger of the two screens for the pump was a very loose fit, so I used the smaller one.
2. Pump outlet
(compete except for QC fitting)
The Durango uses a regulator at the top of the housing. It has a 3/8" QC fitting and it is made from stainless steel. It can be removed by making your own special tool. I used a piece of 1" electrical conduit that had a swaged (bell) end. I used a bench grinder to grind down the end until it fit into the tabs that hold the regulator (see attached photo). Press down on the pipe until the regulator pops free.
Ideally a bulkhead fitting could be used here, but the opening is too large and the mounting tabs get in the way for sealing. My first idea of gutting the regulator and pressing in a stainless weld bung did not work out.
After measuring and giving it some thought, I decided to use a 1-3/8" nylon rod cut to 2" long and drilled for 3/8 NPT on one end and 1/4 on the other (it could all be 3/8, I just had 1/4 x 5/16 barb fittings already). The 3/8 elbow goes on the top side and the 5/16 barb on the bottom. I used some PTFE tape and pressure tested the fitting to about 90 PSI using shop air and holding it in a bucket of water- no leaks. The rod with fittings attached is pressed into the regulator opening. After using some 100 grit sandpaper to roughen both parts, I supported the housing from underneath using a large socket so I could press the rod into place. Even at this, I broke off a few of the regulator mounting tabs- no big deal since they are no longer used. I used JB Weld plastic bonder to glue it into place. New pics are attached of this work. All I'm waiting on is the 3/8" QC fitting, then I can put the unit together and reinstall the tank.
3. Return fittings
I drilled a 1/2" hole (see photos) in the upper housing and used a 1/4 pipe street elbow with a Viton sealing washer on either side of the housing and plan to seal both using Hylomar sealant. The female pipe barb adapter holds it together mechanically. I would not use this setup for the pressure side, but since this is a low pressure return it should not be a problem. After that, I plan to use a combination of the nylon flex hose hose and stainless tubing to make an internal return line. I bent the tubing 90 degrees and drilled a 19/64 hole in the bottom of the lower housing so it can pass through. I then notched the housing leg so the return line can pump fuel away from the pickup under the fuel level. I added a leftover flex hose here to extend it even further. I have attached pics of the completed assembly and the flex hoses attached inside the assembly. These were difficult, I ended up using a heat gun to warm them, and then a forked trim removal tool to push them on. I would have liked to use smooth single-barb fittings but they are difficult to find for some reason- the Russell one I ordered on Amazon came as a multi-barb fitting. The fuel pump seller said the multi-barb works OK with their pump.
(will carryover to another post as this has gotten too long)