440-6 vacuum advance line

[Kuro]

Hey guys!

So I noticed the vacuum advance was disconnected when I got my car.. I wanted to reconnect it and found out that someone had blocked off the connector on the carb with epoxy or something like that (pic attached).

Is it possible to just put a T-piece in the line below and connect the vacuum advance there? They are called "vacuum diaphragm supply tube" I think... Or can I get it somewhere else? I am not looking for power gain, I just want it to be as stock as possible.


Thanks in advance


cheers

 

[Xcudame]

The opening for the vacuum advance tube is located above the throttle blades so there is no vacuum to that port at idle. The tube you're contemplating teeing into has vacuum all the time. I'm thinking you're going to need to replace that metering block to fix your vacuum advance port. Others with more knowledge of six packs may have an alternative solution. But your are wise that you need vacuum advance for decent street driving.

 

[Kuro]

So these are manifold vacuum and the advance port is ported vacuum? Would that be a big issue? I have read and heard people are decvided of which is better.. I really just want to have a little bit better fuel consumption at cruising. It seems way too thirsty even for that big of an engine..

 

[Xcudame]

The vacuum advance port is delayed. Running manifold vacuum to the distributor vacuum advance will cause it to engage at idle and change your timing, increase your idle speed and use more fuel. You really need the blocked off port fixed. It could be as easy as removing that metering block, drilling out the epoxy and soldering in a new tube.

 

[dadeo1852]

Guessing that epoxy or ? would be easy to remove with a pick without removing anything. Clean /vacuum it and the nipple that goes in there is a light press fit so I used a dab of sealer and works great. Then you have a stock setup like this.
Andy

 

[Chryco Psycho]

Vacuum advance must be connected to ported vacuum otherwise the mech advance is going one way while the vacuum is working opposite .
My guess is it runs better without it anyway , I often disabled the vacuum advance & get better results .

 

[Kuro]

Ok so it seems it's not an option to use manifold vacuum then.. Is there any other place where I can get ported vacuum? If not, I'll keep it this way for now I guess.. Can I remove the metering block without taking out the whole carb? Looks close but maybe doable? Does it need to be retuned after? Right now it runs pretty good apart from the missing vacuum advance..

 

[Chryco Psycho]

no Other source for ported vacuum , as I said it probably runs better without it in my experience !
You would have to pull the carb , the correct way is to remove the rear one first to access the center carb

 

[Xcudame]

Running without vacuum advance is fine for a race car as it doesn't do anything at wide open throttle. However, for a street car, you really need it. See link for a great explanation. There's a reason why my 70 Challenger has 250,000 plus miles on it!
Advance To Go

 

[Kuro]

I really wish I could get ported vacuum somewhere else... I'm new to carburated cars, and taking apart the carb as the first thing I do to my "new" car seems a bit much... What a headache this early on

 

[Xcudame]

Drive it as is for now and enjoy. Order a new metering block with the the vacuum port. And once you get the new metering block, change it out. It's not complicated. Any questions, we are all here with in a few hours to help!

 

[Kuro]

What if I would use manifold vacuum and adjust the timing to that? If I would do that, wouldn't it be okay? Like I said, I'm new to this stuff..

 

[Xcudame]

Not going to work. Either live it disconnected (not the best solution) or replace/fix the metering block.

 

[Chryco Psycho]

Irf you connect to manifold vacuum the advance works opposite with full advance at idle decreasing with RPM . Seriously you do not need it .

 

[Daves69]

Normally one would cap the port. Maybe it had broken off?

Maybe just rebuild the carb and repair while apart. I wouldn't think it would be too difficult drill out and install a new tube.
The backside of a 6020 block..........

 

[rklein71]

I had a similar situation, I epoxied a short section of brake line into the hole making sure to not plug the vacuum port up. When the hose was attached, you could not tell the difference.

 

[Kuro]

I apologize if it seems that I'm trying to argue and I really appreciate your help. I really just want to understand how this works before doing anything to it.. I do not like to work on stuff I don't at least somewhat understand..
I was assuming that the difference between manifold vacuum and ported vacuum was that ported is above the throttle plates and manifold is below..
So basically, manifold would have vacuum with closed throttle while ported wouldn't. That much is clear and seems logical to me.
What I do not get is how it would work the opposite after I open the throttle plates? Is there some mechanism inside the carb that regulates the ported vacuum? Because if not (and other carbs I've seen don't look like they have a mechanism, just a port from the connector to the top of the throttle blade - of course I haven't seen too many and worked on even less), shouldn't manifold and ported vacuum be the same after I opened the throttle?


If I run advanced ignition, the car should be - if not too advanced (knocking) - running better (less fuel consumption, more torque) at lower rpms, is that correct? At least that's what we did on EFI engines.. Little throttle opening-> advanced timing... And if I understood correctly, that is what vacuum advance does, too: Advance timing on low throttle input... And since it "should" be the same vacuum after idle (if my theory is correct of course), in theory the only difference between the two would be that manifold vacuum would advance the timing in Idle already..
So if the car runs advanced timing at Idle, would there be an issue that I am simply missing or am I completely wrong somewhere?

 

[Katfish]

I would try manifold vacuum, you have nothing to lose.

 

[Challenger RTA]

The point of this forum is help other to solve problems of others. To draw on others experience and knowledge. It's not that anyone is ageing. It just might be not what you want to do or hear. Or not an understanding by anyone or everyone.

 

[Katfish]

When I first installed Fitech EFI, my gas mileage tanked, couldn't figure out why.
When I checked the vacuum advance, it wasn't doing anything. I found the ported vacuum on the Fitech throttle body was too high in the bore, so it never supplied vacuum during cruise (partial throttle opening), exactly when you need it. Switched to manifold vacuum and adjusted initial a little lower and all was well.

FiTech , No ported vacuum problem