Tank selector valve area pics ?

[Pyrotechnic]

Does anyone have pics of the selector valve area on a unmolested truck ?

Reason is, I suspect some rigging on my truck. The outlet fitting looks like 5/16's instead of 3/8, and the way it's mounted does not look stock. I've seen other selector valves on other trucks in the past, and this one just doesn't match up.

EDIT: Also, the valve currently on the truck is a 2 in, 1 out valve. The vents that are on the fuel tanks consist of a short length of hose, then a plastic breather exactly like the kind for a rear axle vent. This truck is a Heavy Half and had little to no emissions equipment from the factory. I've search through posts and many specify a 6 port valve, which makes sense for a TBI setup, but not for a carb ? I don't see any reason to switch the vent lines ?

[UNDERDOG1]

I have a 6 port on my 79' that has been bypassed to work just one tank,I would be interested in this as well.My sending unitseach have 3 portsand my selector valve has 6 ports.

[moneyeater]

Mine was a 350 diesel originally!
The valve has 6 connections.the second pic shows the passengerside rear cabmount to give you an idea where it sits!

[Pyrotechnic]

Thank you ! Looks like mine is definitely not factory. It looks like the inlets and outlets are all 5/16 on it too. Kinda scary with the power I'm making.

OK, so 3 of the lines on the valve are for fuel, what are the other two for ?

I'm just trying to figure out what valve to buy. I have found both, 3 port and 6 port. I figure if anything I can just buy the 6 port and cap off whats not used. I have no idea what was done under there, but all I have at this point is two supply lines to the valve, and one line going to the engine. Nothing else.

[Prong]

3 ports are for manual trannies and the 6 ports are for auto trannies. On the 6 ports, two are for the tank vents.

[Pyrotechnic]

Thats strange, why would the transmission play a part in the fuel selector valve ? How would the tanks vent on a manual transmission truck with a 3 port valve ? And on a automatic truck, where would the vent line go to ?

My truck is an automatic and has been since day one.

Sorry for the flood of questions, I just want to re do the fuel system in a way that somewhat resembles how it would have come from the factory.

[firedrag79]

I've got a 6 port switch and it has a return line from the motor. So that is why it needs the extra 3 ports. To get the return fuel back to the correct tank.

[Pyrotechnic]

Mine's a returnless system.

Here's another thing. Most of these replacement valves I see are the motorized type with a 6 pin plug. The one I have looks to be a solenoid type with a single wire, and I suppose it gets it ground from the frame.

The motorized style looks like it need 2 wires to operate. When the polarity is reversed on these wires, the valve will switch over. It stays in it's set position even if power is removed

With the solenoid valve, 1 wire is required. The valve defaults to one side and it takes power to keep it switched to the alternate side.

Now with only one wire going to the valve, I can't see how the newer style valve would work without completely rewiring the tank switch circuit ? Though I see lots of trucks with these newer style valves ? How is everyone wiring these ?

[moneyeater]

I found this one! It´s not original but it´s used in our trucks!

http://www.jcwhitney.com/POLLAK-ELEC...2070_10101.jcw

[Pyrotechnic]

Originally Posted by moneyeater

I found this one! It´s not original but it´s used in our trucks!

http://www.jcwhitney.com/POLLAK-ELEC...2070_10101.jcw

It looks like the one you have mounted to your frame. Did you have to modify your wiring or did your truck already have that 6 pin plug ?

[78 Chevyrado]

I bought the service replacement from the chevy dealer on my no emmisions 78 c20. I have the exact setup you have, short piece of hose with a vent on the end (single fuel line) and the one wire hook up. The part number is 15580925 and is still available. You can get it at gmpartsdirect.com for $12-$13 plus shipping. At the dealer, mine was 18.53 with tax.

It's not exactly like the original but works perfectly. Instead of remounting it to the original hole, I found one nearby and rebent the bracket a bit and it was good to go with no other modifications.

If I can remember, I'll try to get a pic of it monday when I go up to the body shop.

[moneyeater]

Originally Posted by Pyrotechnic

It looks like the one you have mounted to your frame. Did you have to modify your wiring or did your truck already have that 6 pin plug ?

I removed the driverside tank and the valve long ago and i completely rewired the truck so i really don´t remember if the wiring was all original but i think so!
Jcw offers one with 6 and one with 3 connections and you´re right the one in the link looks like the one i had!

[Pyrotechnic]

Originally Posted by 78 Chevyrado

I bought the service replacement from the chevy dealer on my no emmisions 78 c20. I have the exact setup you have, short piece of hose with a vent on the end (single fuel line) and the one wire hook up. The part number is 15580925 and is still available. You can get it at gmpartsdirect.com for $12-$13 plus shipping. At the dealer, mine was 18.53 with tax.

It's not exactly like the original but works perfectly. Instead of remounting it to the original hole, I found one nearby and rebent the bracket a bit and it was good to go with no other modifications.

If I can remember, I'll try to get a pic of it monday when I go up to the body shop.

Good to know ! I thought I was the victim of some rigging.

The only thing that's bothering me is that the valve I have now has 5/16 fittings. Looks like one of the parts store universal valves. I'm making quite a bit of power and it bothers me to know I have this kind of restriction in the line. Also, the only reason the hoses seal on the fittings is because of the hose clamps.

Did this particular replacement have 3/8 fittings ?

[78 Chevyrado]

Originally Posted by Pyrotechnic

Did this particular replacement have 3/8 fittings ?

Mine has 3/8 fittings on all 3 ports. Here's basically what the GM replacement valve looks like:
http://cgi.ebay.com/ebaymotors/NEW-U...4506.m20.l1116
This guy wants $60 for it, but you can get it for 15-20 bucks. Mine looks like the one pictured, but Mine has a bracket with it.

[UNDERDOG1]

Does anyone have a pic or diagram of how to change a 6 port to a 3 and the hose routing etc. ?

Thanks.

[Pyrotechnic]

Originally Posted by UNDERDOG1

Does anyone have a pic or diagram of how to change a 6 port to a 3 and the hose routing etc. ?

Thanks.

Once I drop the tanks to replace the lines, I'll see if I can get some pics.

Thank you to all who have replied to this thread. It was a big help and I now have I good idea of what I need to do. I'm gonna go ahead and order that valve. Can't beat the price on it compared to all these parts store replacements that run $60 or more.

[UNDERDOG1]

Pyro, how is this comming along? look foward to seeing how it turns out.

Thanks.

[joe231]

Originally Posted by 78 Chevyrado

I bought the service replacement from the chevy dealer on my no emmisions 78 c20. I have the exact setup you have, short piece of hose with a vent on the end (single fuel line) and the one wire hook up. The part number is 15580925 and is still available. You can get it at gmpartsdirect.com for $12-$13 plus shipping. At the dealer, mine was 18.53 with tax.

It's not exactly like the original but works perfectly. Instead of remounting it to the original hole, I found one nearby and rebent the bracket a bit and it was good to go with no other modifications.

If I can remember, I'll try to get a pic of it monday when I go up to the body shop.

That part number doesn't work any more...any ideas?

here is a pic of my factory 6 port...I'm looking to buy a spare, but can't find a single wire, 6 port





upon further inspection...it has Pollock stamped on it, it appears to be OE though...I haven't found a part number on it.