Thermoquad question

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GDL

GDL

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Ok so I'm tying up the loose ends on the 340 and the large 1/2 inch vac tube on the passenger side of the carb goes to what? Emissions were removed prior to my ownership.
 
I would route it to the air cleaner. That would be most correct since it has no emissions.
 
Charcoal canister. Its the bowl vent. without it hooked up. If the needle and seat stick the fuel will dump onto the hot intake and start a fire. get a oil breather that has a nipple for it like a 71. If you don't have a canister from a 72.
 
Heat doesn't cause gas to ignite. Spark does. He's already dumpin gas into a hot intake straight outta the carb. I have done a BUNCH of them either in the air cleaner or the valve cover breather, whichever is easier and never had a problem. I know you have been doing this longer than I. Have you ever really seen that happen before?
 
Ok, got that squared away and now onto figuring out why I have a high idle in park and a stumbling / weak idle in gear......

And no vac leaks I can see.....
 
Is your vacuum advance hooked to ported or manifold vacuum? Also what's your initial timing advance and what kind of mechanical advance springs are in your distributor?
 
Not sure on timing but the distributor is off the old 2bbl 318 and the vacuum is plugged into the base below the throttle blades.
 
GDL said:
Ok, got that squared away and now onto figuring out why I have a high idle in park and a stumbling / weak idle in gear......

And no vac leaks I can see.....
Click to expand...

Sounds like a vacuum leak. Ease the choke shut. If it continues to run, it has a vacuum leak.
 
RustyRatRod said:
Heat doesn't cause gas to ignite. Spark does. He's already dumpin gas into a hot intake straight outta the carb. I have done a BUNCH of them either in the air cleaner or the valve cover breather, whichever is easier and never had a problem. I know you have been doing this longer than I. Have you ever really seen that happen before?
Click to expand...
Open your hood at night. Some have a circus of sparks from the wires. The alternator is a constant source of spark. The heat just caused the fuel to boil and the fumes are very explosive when the hood is closed.
 
Oldmanmopar said:
Open your hood at night. Some have a circus of sparks from the wires. The alternator is a constant source of spark. The heat just caused the fuel to boil and the fumes are very explosive when the hood is closed.
Click to expand...

I'll go along with that. But what I am asking is, how can that happen if the float bowl vent is routed back to the air cleaner? That's how a Holley IS. They have the bowl vents INSIDE the air cleaner and I've never seen one of them explode.......from that. lol
 
RustyRatRod said:
Sounds like a vacuum leak. Ease the choke shut. If it continues to run, it has a vacuum leak.
Click to expand...

That kills the motor. Lol. We were plaing with it and closed the choke and it died. Just need to tweak with timing I'm guessing.....
 
Vacuum advance should be plugged into the ported vacuum port which is above the throttle blades. I know guys that claim it works plugged into manifold vacuum but IMO it'll never work good that way because the lower curb idle vacuum can let the vac advance drop out then as soon as you touch the throttle the vac comes up and it pulls back in causing an erratic idle. The change in timing can actually change the fuel mixture requirements also further complicating the problem.

BTW: I've rebuilt several TQ's over the yrs. and every one I've seen also have bowl vents that stick straight up into the air cleaner just like nearly every other carb so I don't see why it'd be a problem just capping the emissions bowl vent off. Anybody here tried that?
 
That being said what the flip is a filtered air bleed? Or where can I get one if needed....
 
OK after looking at the diagram here's what you need to do: cap off the manifold vacuum source going to the "green" line and get rid of it. Unplug the other line (pink) which I'm assuming is hooked up to the distributor as your 340 shouldn't have the Electronic Lean Burn system and start the car and idle it; put your finger over the open vacuum port and see if it is pulling vacuum at idle. If it is cap it off and then check any other ports on the carb that only pull vacuum when the throttle is above idle.

Or for now just leave it unhooked and it should run smooth without vacuum advance lol

EDIT: and you don't need a "filtered air bleed" that's some stupid Lean Burn component
 
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