mid '80s solinoid carbs

[GSP7]

Is this a false statement about the mid '80 Carbs with the solenoid ?

Posted on a Chevy forum: below

In the early ’80s, GM incorporated electronic connections to the Quadrajet. The Quadrajet’s primary circuit had a small solenoid installed to control the depth of the primary metering rods. These Quadrajets are difficult to modify for conventional use.

Ive never had one of those carbs with the solenoid, so I dont know what is inside. I thought I read here that you could just remove the solenoid stuff and its a good carb like the late 70s 80 carb..??

How does that solinoid control the metering rod? and APT? Any pictures of the inside?

.

[Kenth]

Other than original use for the Computer Controlled Carbs i would not spend any time on these.

JMHO

[quadrajam]

The carb in the image above is OK. 85 and 86 truck carb. The solenoid connector is
grey as shown.

The ones to avoid as Kenth says are the computer controlled..CCC carbs.
They have a blue or black colored solenoid connector and also another electrical
connector on the driver side down low. Started in 80 or 81 on passenger cars
and continued till fuel injection.

QJ

[GSP7]

The carb in the image above is OK. 85 and 86 truck carb. The solenoid connector is
grey as shown.

The ones to avoid as Kenth says are the computer controlled..CCC carbs.
They have a blue or black colored solenoid connector and also another electrical
connector on the driver side down low. Started in 80 or 81 on passenger cars
and continued till fuel injection.

QJ

So sounds like you are saying the one in the above picture is a good carb to use


.

[Kenth]

Just remove the "Dual Capacity Pump" solenoid and it will function like any other Quadrajet.

[quadrajam]

Maybe I'm having a problem with the terminology being used......
Is not the dual capacity " solenoid" the grey electrical coil up top?

And the dual capacity "valve" the valve down in the carburetor bowl
whose stem interacts with the solenoid?

If you remove the solenoid you will have a big hole in the top of
the carburetor.

If you remove the valve you will be left with a hole that will shunt all
of the pump shot.

And yes, they are very good carburetors. I have several and they run excellent.

 QJ

[GSP7]

I see them for sale local, Ive never had one to look at.  Just confused by the 2 different opinions

[Cadman-iac]

Maybe I'm having a problem with the terminology being used......
Is not the dual capacity " solenoid" the grey electrical coil up top?

And the dual capacity "valve" the valve down in the carburetor bowl
whose stem interacts with the solenoid?

If you remove the solenoid you will have a big hole in the top of
the carburetor.

If you remove the valve you will be left with a hole that will shunt all
of the pump shot.

And yes, they are very good carburetors. I have several and they run excellent.

 QJ

 That was my question a bit earlier on a 17055226 carb. If you leave the solenoid out, how do you pug the hole in the air horn? Is there a plug available that would fill the hole?
 I suppose you could make a metal plate to fit and use the rubber seal to keep it from leaking around the hole.
 I'd like to use the ones I have but I don't want the solenoid sticking out of the top if it's not going to do anything.

 As for the valve in the bottom, does it flow any fuel if the solenoid is not in place?
 Being "dual action" would imply that it does, just less when the solenoid is activated or the other way around.
 In order to "deactivate" the valve you would have to solder it shut, correct? Or does this happen with the removal of the solenoid?

 Leaving everything in place the valve still adds extra fuel that bypasses the jets if I understand the system as explained.

 I took the plastic piece off the bottom of one of these solenoids to see what/ how it works. There's a plunger that extends down when the solenoid is energized and it either opens up the valve further or it restricts it, I'm not sure which, someone else with more understanding of the system will have to clarify that.

[quadrajam]

Best for sure thing to do is remove the valve in the bottom and solder it shut then
screw it back in the hole.

Also you can pour molten lead into the hole to seal it up.  Then you don't have to screw
the valve back in.

You are gonna have to put the solenoid coil back on top so you don't have a big hole in
the airhorn.

The valve is always closed unless the solenoid pushes it open. this will require
12 volts to be applied. It is either open or closed, no partial open.

The valve never has or ever will bypass the jets. It diverted some of the fuel from the
accelerator pump discharge back into the fuel bowl.

......NEXT!

[Cadman-iac]

  Ah, so that's what that damned thing is for. I kept thinking it was something like the APT or power valve Rochester used in the 2GC carbs, because that valve looks exactly like an oversized version of what’s in the 2GC.
 I hadn't looked closely at the passages in the bottom of those Q-Jets,  after seeing that valve I just assumed it was an electric version of the 2GC's vacuum operated valve. My mistake.
 Thanks for setting me straight on this.

[quadrajam]

No problem.
When you get ready to build that 226 I have a couple of proven recipes for
it for stock 350 to mild 406.

QJ

[Cadman-iac]

No problem.
When you get ready to build that 226 I have a couple of proven recipes for
it for stock 350 to mild 406.

QJ

 Thanks, I will take you up on that if I decide to use it. Much appreciated.

[Cliff Ruggles]

Aside from being ugly with that big hunk of plastic sticking out of the airhorn those are excellent units and function fine if you block off that system.  When I used to build those here I just melted some lead from a wheel weight into the passage in the main casting under the valve and smacked it gently with a flat punch and put it together just like any other carb. 

You can also get fancy and cut the top of the solenoid off flat and put some epoxy over it.  You could also make some sort of cover if it really bothers you......