Pulling V.A at idle

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Yote said:
Something I haven’t seen mentioned here but does vacuum can on distributor have adjustment in inlet
(Allen screw in tube) . It is my understanding that it can be adjusted to set when vacuum advance comes into play. Possibly a new can not adjusted or one messed with.
This may have been mentioned before and I missed it.
Don’t take this information as gospel as many on this forum know way MORE than I do . Just a thought.
Yote
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Halifaxhops set the distributor up a while back. Has a #7 arm, thinkn that's 14° crank..but pretty darn sure he put a Allen key adjust can on er
 
MOPAROFFICIAL said:
Haven't read all the replies yet but if this is a scenario where you have a little bit of camshaft and you only have 2 Corner idle as in primary, then there's a good chance you have the throttle blades open too far and the ported vacuum is now active.
If that were the case...you can lower the primary blades at the idle speed screw..then flip the carb over and you see a little flat head screw that adjusts the secondary throttle blades...open them just a hair more to compensate for the lowered primary idle speed... again if that's the case and there not some internal leak that's pushing fuel.
All assuming the timing is set right.
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So the front ( primary) and rear ( Secondaries) are independent of each other?as far as where they sit, throttle flat ( closed, w return spring pulling em shut?)
 
mbaird said:
I would pull the carb , flip it over and set the T-Slots first. Then set your initial timing to whatever brings the rpms to what you want (700 ish). Then reset your idle screws. If it still requires 3.5 turns out you may need to enlarge idle air bleeds.
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I didn't, when I set em, was me n a Vacuum gauge, some many years ago, but was points, and a heavier car then
 
Ironracer said:
So the front ( primary) and rear ( Secondaries) are independent of each other?as far as where they sit, throttle flat ( closed, w return spring pulling em shut?)
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Get the carburetor off. Don't MESS with anything. Flip it over and take a GOOD picture of thethrottle plates and how much of the transfer slots are exposed on the primary AND secondary sides and post that picture. JUST like it is.
 
Mattax said:
So odds are that its already advancing. When the engine slows down (transmission placed in gear) timing decreases. How much depends on how quick the primary advance is. it can be pretty dramatic as illustrated above. If you have four hands and an extra foot you can see that in the timing light and tach. Just be careful if measuring timing in gear! The extra hands and a foot on the brake is better than relying on chocks alone.
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This alone is why I like to fill in the inner side of the advance slot and not the outer side when limiting advance. The inner fill in tensions the springs more and reduces the chances of timing drop out when pulled in gear. Moves the rpm that advance starts showing up a bit higher than at idle or right off idle.

If you like the level that your advance is all in, then the inner is the play. Fill the outer and springs need more tension to control the weights.
 
Ironracer said:
The only time I've tried to Tune er, was when I first started Streeting as a Daily Driver.. found an Article on FBBO, using a vacuum gauge, about 2500 Rpm, then bringing the screws in till highest idle, + best vacuum
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Unfortunatelty thats misleading. Using the vacuum as an indicator of power can be useful, but only certain situations. For example, Given the same rpm, same throttle position, and same load. There is no load in park (and neutral) other than engine friction (and driving the transmission pump). An engine can be run extremely lean when there is no load. Lean is less dense fuel-air mix and therefore slower flame development, needing more time.
 
RustyRatRod said:
Get the carburetor off. Don't MESS with anything. Flip it over and take a GOOD picture of thethrottle plates and how much of the transfer slots are exposed on the primary AND secondary sides and post that picture. JUST like it is.
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Ok, may take me a day or so. I'll probably have to get another gasket... I'm gonna be jumping around a Lil bit
 
RustyRatRod said:
Get the carburetor off. Don't MESS with anything. Flip it over and take a GOOD picture of thethrottle plates and how much of the transfer slots are exposed on the primary AND secondary sides and post that picture. JUST like it is.
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20220512_181459.jpg


20220512_181456.jpg
 
Carb is a 3310-12 lower #, 1020... I can't even See a transfer slot... looked for pics too... maybe I'm a special kinda stupid... or just blind! Ok after getting some glasses, and a flashlight, AND pushing the secondary flaps open, I can see these. Thanks @RustyRatRod for the idea of a Baseline, with out jumping all over, and making a mess of things! The gasket stayed on the intake, but it did get wet w/ fuel. Hope it will be re usable
 
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Bewy said:
Timing jumping is probably the engine vacuum trying to pull in the VA plunger but vac is not high enough or stable enough.
So you need to check the T slot as per post #9. Too much T slot gives a rich idle, another one of your symptoms. What size engine, cam?
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Man, looks to me like there is No T slot Showing at all... the rear blades are closed tight...
 
Ironracer said:
Hi Everyone, Hope All Y'all, Your Family's, Friends, and any one else are all Well! I have a quick (I hope) question.
Had a Distributor done. Finally had a Bro come by to watch the tach and run the mat pedal. Before he stopped in, I checked the idle airs... 3.5 turns out ( a buddy "helped" do that when i went to the store)
So, when I set the timing ( Vac Advance disconnected, plugged hose) it was close to where it was supposed to be...
BUT, plugs were ugly, pig rich, ( pulled em and posted em here, different post)
Anyway, when I hooked up the VA, the idle snapped back to "life"! Sounded Way Tight, like it should! Question is : Why am I pulling Vac advance off Ported Vac?
Thanks Everyone!
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You running a MSD?
 
RustyRatRod said:
That first blurry pic the slot appears much more exposed. AM I seeing that right?
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Post #59? I don't even think I knew what I was taking a pic of! Lol #61, is the Secondary, with my finger poking the blades open to see the t-slot. Need a fresh pic, without the blades pushed open? The slot is hidden then
 
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Ironracer said:
View attachment 1715927895 pic of Secondaries... WITHOUT me pushing the blades open... lol. Think my dumbass killed to gasket...
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And the primary picture was with the blades all the way closed. They are a little more the square. I would square them up and crack the secondaries just a LITTLE. Dont crack them enough to expose any of the t slots. Just a little.
 
Ironracer said:
Haha, Cool Man! Made a water neck one outta a notebook cover round 30 years ago. Lasted years!
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You're not in a pinch, so you want a gasket that will actually last. What thickness gasket do you have? It needs to be one of those thick insulator gaskets with this ethanol fuel. Even if you run non ethanol, I would still run one.
 
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