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OK, I currently have an Autolite 1100 on a 1976 I6 200 motor in my wife's 65 Vert. I have the Duraspark II distributor. I was having some issues with the carb and getting it to run smoothly. Because the carb is a SCV carb a few suggested that I run the distro vacuum line to the manifold vacuum port not the carb's port. I did. The manifold had a T that was split between the brake booster and the C4. I actually had to get another T and share the manifold port with the C4 transmission vacuum line. So there is three items sharing the manifold vacuum port. The PCV hose is connected to the port on the carb spacer. I also blocked off the vacuum port on the carb with a bolt and wrapped the threads with some Teflon tape.

I haven't tried to run it yet. Is there anything else I am missing or have failed to do.

I don't have these issues on my D Code Coupe. The 4100 carb is simpler. I just want the car to be worry free so my wife feels comfortable driving it without worry it'll crap out. Eventually I may go the Sniper 1100 route.
 

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Why not fire it up and see how it runs? It sounds like you've identified and taken care of any potential vacuum leaks.

I have no power accessories in my car, other than power steering, so I don't know much about vacuum assemblies. The vacuum port on my intake is blocked with a square plug. The vacuum line on my 4100 just goes to the dizzy, and the port on the carburetor spacer goes to the PCV valve on the passenger side valve cover. Somebody who is more familiar with vacuum accessories and the best places to plumb them will hopefully pitch in.
 

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Any distributor with a vacuum advance diaphragm is designed to run off of "ported" vacuum. To define "ported" vacuum, this is the vacuum above the throttle plate(s), which uses a hole and circuit above the throttle plate to deliver "ported" vacuum to the distributor as the throttle opens. Applying direct vacuum to the distributor at idle will give premature vacuum advance, forcing you to retard the timing to compensate.
 

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Cars were setup for years to have the vacuum advance connected to manifold vacuum. Then came air quality concerns.
Pre catalitic converter smog strategies moved the vacuum advance to ported, Decreased initial timing (sometimes to ATDC) increased centrifugal advance to try and get back to old total advance number. Then air injection systems were added to put more oxygen in the exhaust manifolds. This was all done to create some of the after burn in the exhaust system that was later done with the cat converters.

Basically it was a mess, didn't work well, performance suffered, cars ran like crap.

OP, I don't know how your car is setup. How the dist is curved, what vac advance can is on it. .... But thought I would share a bit about why cars had ported vacuum source for the advance in those years.
 

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FF, sorry, but you are mistaken. Ported vacuum was created solely to increase engine temperature at idle, in the hope of the extremely hot exhaust burning off some more hdrocarbons in the exhaust manifold. Mike is right here, before emission control, there was manifold vacuum advance. LSG
 

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Long, but really easy to understand explanation on vacuum advance using the manifold port in Big Chuck's post, #20.

 

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What Mike and LSG are saying is true, ported vacuum was used as a method of regaining timing in the late 60's until EFI and computers took over from carburetors completely. The low static timing specs required the throttle plates to be open more to sustain an adequate idle RPM, which allowed more air into the engine. This tended to cause run-on or dieseling, which required the fitting of a throttle position solenoid to close the throttle when the ignition was turned off (some mistakenly call this a "kick up" or "AC idle up solenoid"). All of the parts have to work together to have a satisfactory running engine. Problems arise when Joe Backyard decides that any emissions controls are bad, and then can't figure out why his car now runs like complete garbage.

This is one of the Ford manuals that fully explains the emissions controls and how they function. A good read if you find stuff like this interesting.



That said, I've run both ported and full manifold. My preference is ported with a couple caveats. I'm not running factory initial timing specs, and my vacuum advance is tuned to the engine, not an out of the box generic setup.
 
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My I6 ran better with manifold vacuum vs ported. This was with a mild cam and a Holley 0-7448. Since then with the new engine build I kept manifold vacuum hooked up with the FiTech.

You might have to adjust your timing. Ported vacuum makes your curve come in slower.
 

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FF, sorry, but you are mistaken. Ported vacuum was created solely to increase engine temperature at idle, in the hope of the extremely hot exhaust burning off some more hdrocarbons in the exhaust manifold. Mike is right here, before emission control, there was manifold vacuum advance. LSG
Let's take the time to back up statements.
1956 Ford with road draft tube before PCV valves, dual diaphragm distributor with spark control valve, designed to prevent detonation due to the vacuum advance getting full manifold vacuum, venturi vacuum passage (ported) above the throttle plate counter acts full vacuum advance using throttle position. Citation: 56 Ford Shop manual pages 74-75.
"Ported" vacuum later defined as carburetor spark port, citation: Drive-ability Basics Emissions Control Systems Ford Motor Company Course 0901-017.
1964 Fairlane Shop Manual Supplement, page 89, Ford single barrel carburetor explosion showing spark control valve and distributor vacuum adapter (for the vacuum line) clearly above the throttle plate. No opinion can change that.
1966 Comet, Falcon,Fairlane, and Mustang Shop Manual page 10-30 has a nice illustration of the Spark Control System showing the ported vacuum, page 10-32 shows the single barrel carb with spark control valve.
Hydrocarbons (HC) can be indirectly increased by detonation through a lean misfire, but the primary function of spark control through ported venturi vacuum is controlling detonation. To a lesser extent, Oxides of Nitrogen (NOX) can be controlled by spark-vacuum management, but that was inefficient leading to development of EGR systems. Spark control, EGR are designed to lower combustion temperatures thus lowering NOX. Thermactor was designed to lower HC by providing more oxygen to the exhaust manifolds to burn the excess HC.
The ball is in your court.
 

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FF, you're proving my viewpoint and you don't even realize it, because you don't understand how the system works. Ported is an emissions gimmick, YES, EVEN in 1956. I can read it for you, but I can't understand it for you. Haagen-Smit & Beckman had 'smog' figured out in 1948, and were selling measuring equipment in 1952. Yes, it was being worked on even then. The first REQUIREMENT IIRC, was for a PCV in 1961. But auto manufacturers KNEW this kinda thing was coming and they didn't want to be blamed for smog, so they began to try to work on the issue as soon as they knew, early 50s. LSG
 

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What’s not being said is for every application the distributor would be specifically be set up for that one application. Manual and automatic would have completely different specifications. The rate and amount of both mechanical and vacuum advance would be different. Some times even the coil. Automatic applications would have more initial timing and less mechanical then a manual transmission.

when emissions got involved things drastically changed. For instance on EGR you would have far more vacuum advance then non EGR cars from the 60’s. With EGR sometimes you could have as much as 60* vacuum advance while a 60’s car have mid 20* vacuum advance. Too much vacuum advance under light throttle can cause surging and mis fire. If you’re going to run a late model emission distribution in a older car with a older model carb, you should be calibrating the new distributor to the older distributor specs
 

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FF, you're proving my viewpoint and you don't even realize it, because you don't understand how the system works. Ported is an emissions gimmick, YES, EVEN in 1956. I can read it for you, but I can't understand it for you. Haagen-Smit & Beckman had 'smog' figured out in 1948, and were selling measuring equipment in 1952. Yes, it was being worked on even then. The first REQUIREMENT IIRC, was for a PCV in 1961. But auto manufacturers KNEW this kinda thing was coming and they didn't want to be blamed for smog, so they began to try to work on the issue as soon as they knew, early 50s. LSG
I did explain how the ported system works in my first citation, what do you have to disprove that? Calling the system a gimmick and citing public domain is just deflecting. Due to the large variety of Ford produced vacuum port-spark port systems, you pick one, related to a 65 or newer Mustang and tell me how you think it works. I want you to prove to me that I made a incorrect statement since you believe each Ford system is a gimmick, and explain why it is a gimmick.
 

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FF, read pages 22-25 in the document that H-Killer provided. Ported vacuum was a method, a gimmick, in my parlance, to increase temperature at idle. The way the carb is setup goes wth this. Again, if you don't know what it is for, I cannot understand it for you. I will ALWAYS choose a single vac distributor, and run it to full manifold vacuum. YES, you have to do some tuning to get to be the best it can be. You can change the static, you can change the centrifugal, and the better vaccum cans are also adjustible. I don't care if it came that way from the factory or not. I'm going for what runs best. It is worth noting that the hydrocarbon stew we call gasoline is very different now than it was in the late 70s, which is different than it was in the late sixties, and different again from the early sixties and the late fifties. The stock settings, for advance and vacuum were for the gasoline of the day. We can't use 50 year old specs as gospel, because the fuel is not available that works with those specs. We have to use the fuel available NOW, and do what is needed to get the best results NOW. I use full manifold vacuum to an adjustable vacuum can with a single diaghram. Its simple, its clean, and it works very well. But it is not how my car came from the factory ( 1969 ). My factory dual diaghram and DVCV were replaced as soon as I got the car ( 1981 ). Not sure what citation you're looking for, I don't think you understand how your engine runs, and why it does what it does. LSG
 

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Nice one LSG. I'm with you all the way! This has also been beaten to death in various US car forums I'm registered on here in Germany. We have beaten this black & blue & the best way I explain the difference between Manifold & ported vacuum is to tell the guys to hook up 2 vacuum gauges. One of them on ported, the other on Manifold. The only difference is at idle. Once the throttle is cracked open both values are the same up to WOT.
So yes, the advanced timing at idle from the manifold vacuum will let the engine idle not only smoother but much cooler as well.
 

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FF, read pages 22-25 in the document that H-Killer provided. Ported vacuum was a method, a gimmick, in my parlance, to increase temperature at idle. The way the carb is setup goes wth this. Again, if you don't know what it is for, I cannot understand it for you. I will ALWAYS choose a single vac distributor, and run it to full manifold vacuum. YES, you have to do some tuning to get to be the best it can be. You can change the static, you can change the centrifugal, and the better vaccum cans are also adjustible. I don't care if it came that way from the factory or not. I'm going for what runs best. It is worth noting that the hydrocarbon stew we call gasoline is very different now than it was in the late 70s, which is different than it was in the late sixties, and different again from the early sixties and the late fifties. The stock settings, for advance and vacuum were for the gasoline of the day. We can't use 50 year old specs as gospel, because the fuel is not available that works with those specs. We have to use the fuel available NOW, and do what is needed to get the best results NOW. I use full manifold vacuum to an adjustable vacuum can with a single diaghram. Its simple, its clean, and it works very well. But it is not how my car came from the factory ( 1969 ). My factory dual diaghram and DVCV were replaced as soon as I got the car ( 1981 ). Not sure what citation you're looking for, I don't think you understand how your engine runs, and why it does what it does. LSG
So your viewpoint is that ported vacuum is there to increase temperature to control HC, got it.
My point, along with FoMoCo, is that ported vacuum helps control vacuum advance during off idle and acceleration. The purpose of ported vacuum to the dist is to control detonation, (think spark valve) been that way before mandated emissions, and it is still a good idea today. A dist in the ported system gets manifold vacuum at idle, I never said it did not. Then, to repeat, ported vacuum counter acts the manifold vacuum to control total vacuum advance at a particular throttle opening to control the rate of advance to control detonation. I did not make this up, read it in the Ford manual. Ported vacuum systems first used the spark valve, to control detonation, not emissions of hydrocarbons. Also, higher combustion temperature with bad spark timing can cause detonation. Not another situation made up by Ford engineers, who regarded detonation as a bad selling point for their cars.
Moving on to the Mustang era, preventing detonation and improving emissions had to work hand in hand, so when the novice sees many vacuum lines in a Dist Vacuum Control Valve system, they think of emissions control and forget that detonation can be bad for emissions too. DVCV systems do use the spark port, that I cited earlier. The spark port is ported vacuum. It is there to control advance rate which controls spark timing. Along with water temp vacuum valves, electric vacuum valves, ported vacuum was a cheap way to deliver a more responsive vacuum signal using the venturi.
Also, I like the Ford engineers method of using an air pump to control HC to meet the standards of the time. I don't think they could have pulled it off by timing curve alone.
 

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Nice one LSG. I'm with you all the way! This has also been beaten to death in various US car forums I'm registered on here in Germany. We have beaten this black & blue & the best way I explain the difference between Manifold & ported vacuum is to tell the guys to hook up 2 vacuum gauges. One of them on ported, the other on Manifold. The only difference is at idle. Once the throttle is cracked open both values are the same up to WOT.
So yes, the advanced timing at idle from the manifold vacuum will let the engine idle not only smoother but much cooler as well.
You are correct only because an ICE is an air pump. Venturi port vacuum is more responsive, watch your gauges! Without ported vacuum controls, backing off your timing to prevent detonation is your only choice.
 

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So here is my concern regarding using full manifold vacuum as a performance enhancer
If you set your static timing to say 14 degrees and your vacuum advance adds say 6-8 degrees when you are idling you have 20-22 degrees advance
As soon as you get your foot into it you essentially retard your timing back to 14 degrees and are now waiting for the rpm to go up to bring in the mechanical advance.
Is this correct thinking ?
I can't understand how that will improve my performance "off the line" ?
Why not just increase the static timing to 20 degrees ?
 
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