dual tank to single tank question

[ryanss22]

So im going to be replacing both tanks with a bronco tank on my OBS to make my dual pump fuel system eaiser. I removed the fuel tank selector valve on the frame and will prolly take out the tank selector switch in the cab. My question is will I be able to do all this and not throw any check engine lights or have any electral problems? will the SS braided 3/8 line I currently have going to the heads flow enough fuel for 300/200 hybrids or should I jump up to 1/2 line??

 

[Brain's 97 Diesel]

IDK about the fuel line, but you can put a 38 gallon rear tank in. Spectra makes it, F26e is the model. This was used as an option for mid/late 1990s trucks for the rear. minor mod needed, also pull the bed it makes it so much easier.

 

[ryanss22]

My new bronco tank just came in, along with my weld on fuel sump kit. Just have to figure out the straps for the tank is all...

 

[Bobby@cp]

No codes will be thrown or anything, if it were me I would jump up in line size but thats just me..... Someone with more knowledge will come along.

 

[DZL JIM]

I'll second the F26E.
I've done both the Bronco and 38 gallon tanks and the 38 is a far better way to go.

 

[ryanss22]

Little late for the 38 gallon tank.. Oh well. I'm going to run 1/2 line from the tank to the filters and pumps

 

[old man dave]

You should leave the fuel selector valve electrically hooked up just so the fuel guage will work.

Use 5/8 hose from the tank to the fuel pump and to the y-fitting. Then you could use 3/8" to the heads.

 

[ryanss22]

^ good point about the fuel gauge not working. the sump kit came with 1/2 npt bungs welded into it. so it looks like I'll be going 1/2 to a Y to the dual sd pumps

 

[KBMKVIII]

I used 5/8 from the dual pumps to the valley.
And front tank is sumped.
Also used a small transfer pump on a switch between tanks to refill it whenever I need to.
Also drilled out the fittings in the back of the heads.

 

[ryanss22]

KBMK- what fittings at the back of the head did you drill out? how big did you go?

 

[KBMKVIII]

I can't remember exactly.
Ill try to find the bit tonight.

 

[ryanss22]

what was it that u drilled out on the heads?

 

[KBMKVIII]

Fittings that go into the back of the head.
Drilled them out to make less flow restriction.
There should be someone else here that can remember
the specs on sizing.

 

[old man dave]

1/2" NPT is larger than 1/2" hose. You should be able to run AN-10 (5/8") hose to them.

The fuel rail gallery plugs at the back of the heads, (firewall side) can be modified by brazing the tit off of a steel AN-6 fitting to it and drilling through the fuel rail plug/brazed AN-6 tip. Aeroquip sells the largest ID AN-6 male fittings, Earl's have the smallest ID. When drilling out the ID of the fittings, you have to leave a slight amount of "shoulder" to seal the fitting. Diesel Innovations sells these fittings ready made, (about $20 each?). Areoquip sells a close bend sweep AN-6/90* braided line fitting that fits or they also have a pushlock hose sweep AN-6/90* fitting that fits. The wide bend 90* do not have enough clearance to the firewall to fit properly. When doing this, the stock 1/8" NPT fuel fittings are just plugged off. Run the hoses to a Y-block and then back to the fuel pump/filter setup. The stock fuel return hoses at the front of the heads are run to a pressure regulator and then use the stock 3/8" hose to return to the fuel tank or selector valve for the fuel return.

 

[FrankTheTank]

Would it be easier to drill out the frt ports on the heads and use the rears as returns or is the space on the frt ports just as confined to get something larger in there

 

[Clipper]

My new bronco tank just came in, along with my weld on fuel sump kit. Just have to figure out the straps for the tank is all...

Kit? I was thinking about skipping the sump and doing just a 90* fitting welded on. Do you have a pic just for reference? Also, jeffs bronco graveyard sells the bronco straps if you need them.

 

[old man dave]

Fittings that go into the back of the head.
Drilled them out to make less flow restriction.
There should be someone else here that can remember
the specs on sizing.

The AN-6 fitting is basically 3/8" bore sized. When you look at an AN-6 male fitting there is a flat "shoulder" section between the bored hole and the threaded section. I left about 0.050" width after drilling it out (less than a 1/16"). The fitting uses this section to seal on and my AN-6 fittings sealed up just great with this width of "shoulder" and it did not weaken the fitting (left enough meat for strength). Any good drill set (1/64"ths) will have the bit you can use.

Use the modified fuel rail plugs in the rear of the heads then you can use the stock fuel return lines off of the front of the heads as the return lines to the pressure regulator. Mount the pressure regulator at the front of the engine valley or off of the rear of the hpop reservior.

RockAuto has tank straps for less than $20 a set.

 

[old man dave]

Kit? I was thinking about skipping the sump and doing just a 90* fitting welded on. Do you have a pic just for reference? Also, jeffs bronco graveyard sells the bronco straps if you need them.

Part of the advantages of a sump is pulling fuel from a low spot in the tank, just a fitting does not do this. Some have made sumps by welding a small auto trans pan or simular to the bottom of the fuel tank and then welding the fitting into the pan.

 

[FrankTheTank]

The f26e? Tanks have a small depression in them right in the center of the tank. If u weld a 90* fitting in that depression it should act as a sump. Maybe not as efficient as a true sump but it should work just fine.

 

[m j]

shouldnt need straps, the factory skid plate fits the brono tank I have.
just a slight mod to get it to locate the tank fore and aft.

I wouldnt braze anything, let alone a pressurized fuel fitting. braze is surface adhesion, if you want it welded then weld it.