Fuel Tank Selector Valve Porting

[Ronno6]

I received my dual tank selector valve yesterday for my '84 C-10.
Fuel supply ports are 3/8", the correct size.
The return ports should be for 1/4" hose, but they are 5/16"

Are ALL selector valves like that now??

Now that i have a new selector switch I have verified that my old valve is working.
Should I just re-install the old valve and return the new one, or is there a 5/16" to 1/4" hose barb I should use??

 

[75gmck25]

I would just buy some standard fuel hose barbed adapters and use them to make the new switch work with the 1/4” line. If you can’t find them at the parts store, I’m sure you can get them online. I’ve also found a few brass hose adapters at Home Depot. They are usually stocked where they sell plastic hoses, near the shelves for the various plumbing repair kits. You will need to put clamps on each one because there is pressure in the return line.

 

[Ronno6]

Space is at a premium for installing a reducing splice...at least one that is the full 2"long...
I may need to trim the length...
How much pressure does the return hose see? There is no real restriction in the line to induce back pressure.....

 

[Ronno6]

A heat gun is a wonderful thing..............
A little heat and the 1/4" fuel line went on to the 5/16" barb of the valve no problem........
Now, the fun starts............putting it all back together.........

 

[SquareRoot]

I replaced my entire setup recently on my 85 when I switched to EFI and in-tank pumps. My 6 port Pollack valve has 3/8 inlet, 5/16 return and the 1/4 is for the vents. Might want to verify yours is hooked up correctly.

 

[Ronno6]

I replaced my entire setup recently on my 85 when I switched to EFI and in-tank pumps. My 6 port Pollack valve has 3/8 inlet, 5/16 return and the 1/4 is for the vents. Might want to verify yours is hooked up correctly.

The OEM valve had 3/8" nipples for fuel supply and 1/4" nipples for the return
My sending unit has the 1/4" line just going thru the top plate to an open pipe on the inside. I believe this to be for the return.
The middle is the 5/16" line and it enters a canister sort of structure just under the mounting plate. I believe this to be the vent line.
The metal vent lines are 5/16"
All signs point to those sizes as being correct.....

 

[SquareRoot]

Interesting. Maybe they were different after 84? Now that I think about it, all my parts were ordered for an 87 which had switched to TBI that year. With the higher fuel pressure, it would make sense to increase the return line since the pumps were now in the tank.

 

[Ronno6]

I suppose in an effort to make the valves "universal" they used the later port size for the return.
The heat gun softened the hose up so that 1/4" easily slipped over the 5/16" nipple.
The passenger tankis back in (after a pretty good struggle) and now...........I gotta do the plumbing........

 

[MtBraun]

I received my dual tank selector valve yesterday for my '84 C-10.
Fuel supply ports are 3/8", the correct size.
The return ports should be for 1/4" hose, but they are 5/16"

Are ALL selector valves like that now??

Now that i have a new selector switch I have verified that my old valve is working.
Should I just re-install the old valve and return the new one, or is there a 5/16" to 1/4" hose barb I should use??

Did you go with a 6 port Pollack valve? If so, what was the part number? I think its 42-151 but would like to confirm before I order. Thanks.

 

[dusterdude]

The return hoses are 5/16 and the vent hoses are 1/4

 

[Ronno6]

Can't remember the part #.....sorry...
But, I broke it anyway. Had to re-install the original....
It's working at present.

 

[Copakekid]

I am also having the same problem. Original valve has 1/4" Ports for the top two on the side of the valve with 4 ports. I ordered a replacement valve from LMC trucks and the new one has 5/16" ports instead of 1/4".

Lines coming from the tanks on mine are the original 1/4"

Also checked the one from Advance Auto Parts, same thing, 5/16" ports. All of the websites show the connector side of the valve so you can't see the other side. If they do show a picture of the 4 port side, the ports have rubber caps on them.

Not enough room for a reducer in the area of the valve, or anywhere else that wouldn't be a pain to get too.

Any suggestions on a direct fit valve that is in fact direct fit, or other solution?

I will try the heat gun trick to see if that works if that's the last resort.

Replacement parts suck nowadays. I guess "direct fit" means it will fit somewhere on the truck but not necessarily fit like the original.