What happens when you run the engine with the vacuum to the distributor disconnected?
#1
What happens when you run the engine with the vacuum to the distributor disconnected?
Hmmn, I considered signing up as a new user so you wouldn't know who was dumb enough to do all this but I decided to fess up to it. Have you ever had a dumb blonde moment that lasted all day long?
1962 223cu in w/1963 style autolite 1100 carb
I've had issues, smoking and symptoms of a vacuum leak, and an inspection of a sticky power valve was brought up. So I took the top off of the carb, cleaned it up and checked it out. The power valve was fairly free but sticks every once in a while. I soaked it and put it back on today. As soon as I had everything hooked up (or so I thought) I looked in my magnetic holder and saw the main fuel jet still sitting there
First I got ticked, then I thought maybe this would be an opportunity to test it and see if it ran better without it, maybe that would help me diagnose my problems. So I started it up... and it ran great, smoother than normal and needed only half choke instead of almost full choke to maintain a cold idle. IT held idle at lower speed than normal and I wouldn't be surprised if it would have gone choke-less after it warmed up. Also there was a LOT less smoke, almost none.
The problem is that it only ran for about 30 seconds and then it died. I assumed that I must have flooded the engine but I didn't smell gas so I looked out under the hood and discovered mistake #2. I hadn't reconnected the vacuum line to the distributor
So I hooked that line back up and now it won't start, it cranks healthy but won't start. I'm assuming I messed up something with the distributor now. Does it have to build back up vacuum to the distributor or what have I done and how can I fix it? Or is the distributor fine now and i've just flooded the heck out of it because it has no jet. Also, what does the fact that it ran much better without a jet and no vacuum to the distributor mean?
Thanks guys, I think i'll stay out of the garage and away from heavy machinery for the rest of the day.
Joe
1962 223cu in w/1963 style autolite 1100 carb
I've had issues, smoking and symptoms of a vacuum leak, and an inspection of a sticky power valve was brought up. So I took the top off of the carb, cleaned it up and checked it out. The power valve was fairly free but sticks every once in a while. I soaked it and put it back on today. As soon as I had everything hooked up (or so I thought) I looked in my magnetic holder and saw the main fuel jet still sitting there
First I got ticked, then I thought maybe this would be an opportunity to test it and see if it ran better without it, maybe that would help me diagnose my problems. So I started it up... and it ran great, smoother than normal and needed only half choke instead of almost full choke to maintain a cold idle. IT held idle at lower speed than normal and I wouldn't be surprised if it would have gone choke-less after it warmed up. Also there was a LOT less smoke, almost none.
The problem is that it only ran for about 30 seconds and then it died. I assumed that I must have flooded the engine but I didn't smell gas so I looked out under the hood and discovered mistake #2. I hadn't reconnected the vacuum line to the distributor
So I hooked that line back up and now it won't start, it cranks healthy but won't start. I'm assuming I messed up something with the distributor now. Does it have to build back up vacuum to the distributor or what have I done and how can I fix it? Or is the distributor fine now and i've just flooded the heck out of it because it has no jet. Also, what does the fact that it ran much better without a jet and no vacuum to the distributor mean?
Thanks guys, I think i'll stay out of the garage and away from heavy machinery for the rest of the day.
Joe
#2
#3
You probably flooded it without the main jet at the same time you leaned it out the carb with too much air due to the vacuum line being disconnected, so they may have sorta cancelled each other out, at least for the 30 seconds it ran.
Put the jet back in and it should help. Carbs don't work without a main jet.
Put the jet back in and it should help. Carbs don't work without a main jet.
#4
#5
You probably flooded it without the main jet at the same time you leaned it out the carb with too much air due to the vacuum line being disconnected, so they may have sorta cancelled each other out, at least for the 30 seconds it ran.
Put the jet back in and it should help. Carbs don't work without a main jet.
Put the jet back in and it should help. Carbs don't work without a main jet.
I inspected the main jet and I found some crud in it. I cleaned it out, it was stubborn, but it's clean now and the jet orifice is visibly larger. That should help things out a bit. I tore the carb back down and installed the jet again. The truck fired for me a little but I think it's super flooded. I'll try 'er again tomorrow, i'm expecting good things with that jet cleaned out now.
#7
Trending Topics
#8
What???? at idle you should have no vacuum at the vacuum advance pot. you should be using the timed port on your carb.... disconnecting the hose at idle will have no effect, and you should not feel any vacuum if you are using the correct timed port! If you use the untimed ambient pressure port, on the carb for your advance you will have pretty noticeable backfiring, when the engine is coming down on compression.. The Vac Advance pot on the dizzy is their to increase the advance under load... aka a heavy pull at lower RPM..when the vacuum drops. At Higher RPM the weights in the Dizzy will swing out and increase the advance mechanically, at higher RPM you have lower vacuum pressure so the vac pot will pull less advance. The combination of Vac advance, and Mechanical advance (The weights) , is called total advance.
So having the hose disconnected at idle should have no effect, if it does you are on the wrong port on your carb... if both ports have vacuum pressure at idle, then your carb has a problem.
Timing Tips for Ford Distributors
Ignition timing - Wikipedia, the free encyclopedia
here are a few articles to help explain it!
#9
What???? at idle you should have no vacuum at the vacuum advance pot. you should be using the timed port on your carb.... disconnecting the hose at idle will have no effect, and you should not feel any vacuum if you are using the correct timed port! If you use the untimed ambient pressure port, on the carb for your advance you will have pretty noticeable backfiring, when the engine is coming down on compression.. The Vac Advance pot on the dizzy is their to increase the advance under load... aka a heavy pull at lower RPM..when the vacuum drops. At Higher RPM the weights in the Dizzy will swing out and increase the advance mechanically, at higher RPM you have lower vacuum pressure so the vac pot will pull less advance. The combination of Vac advance, and Mechanical advance (The weights) , is called total advance.
So having the hose disconnected at idle should have no effect, if it does you are on the wrong port on your carb... if both ports have vacuum pressure at idle, then your carb has a problem.
Timing Tips for Ford Distributors
Ignition timing - Wikipedia, the free encyclopedia
here are a few articles to help explain it!
So having the hose disconnected at idle should have no effect, if it does you are on the wrong port on your carb... if both ports have vacuum pressure at idle, then your carb has a problem.
Timing Tips for Ford Distributors
Ignition timing - Wikipedia, the free encyclopedia
here are a few articles to help explain it!
That being said I did stick my finger over the hole for the vacuum advance line while it was off and the engine was at idle. It had some vacuum, not a lot but some. I did the same once with the PCV port on the intake manifold under the carb and it will about suck the skin off your finger at idle, this was nothing like that. Probably just enough to hold a tissue up against itself. Does that indicate a carb problem?
But, this was when it was running with no main jet and it was compensating for the extra fuel. Maybe with a jet installed if I tried it again I would feel more vacuum from that port?
Classic Inlines Ford Six Loadomatic Distributor & Spark Control Valve
#10
After reading about the loadamatic'' dizzy I ''Agree with ''Jetcopter Pilot'' you should still not have vacuum at idle speed and increase on throttle unless I'm just DIZZY'' and reading wrong, but I've never heard of having vacuum at idle?
Sounds like you have something hooked up wrong? plus maybe a rebuld is in order for the carb?
Sounds like you have something hooked up wrong? plus maybe a rebuld is in order for the carb?
#11
[QUOTE=tymatt67;10719417]Vac adv has all the vacuum at idle and none under acceleration or at least almost none. With the vacuum held at idle it advances the timing and under acceleration it retards it a little to prevent pre ignition.
vacuum increases as you go from idle to higher rpms...the vac advance retards and advances
timing...that's why you disconnect it during initial timing adjustment.
JBone
vacuum increases as you go from idle to higher rpms...the vac advance retards and advances
timing...that's why you disconnect it during initial timing adjustment.
JBone
#12
I will disagree with many of the posters to state you HAVE and DO need to have have vacuum at idle! (CropDusterMan, you are describing ported vacuum, which is different, ...more on that later)
The dizzy hose should be connected to manifold vacuum, not ported vacuum, due to the fact that the fuel/air mixture is leaner at idle and therefore 'needs to have the fire lit' sooner. The vacuum to the dizzy provides a timing advance for normal operation at idle. Same condition occurs at steady highway speeds where you also have lean mixtures and high vacuum.
For timing at idle during tuning, disconnect the vacuum hose at the dizzy to disable the advance that otherwise NEEDS to be present!
The theories regarding ported advance were ill-thought-out when emission control was coming into awareness (1970's) and the idea was used to raise the engine temperatures by leaning out the fuel/air ratios and causing the engines to run hotter and (in a way) more emissions-free.
I have not recently read any of the referenced articles, but I believe I have read them or similar ones in the past. However, there are many articles that support my statements and if you take the time to read them, I believe you will agree with what I have just said.
For the benefit of those that may not know, ported vacuum comes basically from the carb above the butterflies and manifold vacuum comes from below the butterflies. Therefore, with ported vacuum, at idle and the butterflies closed, there would be basically NO vacuum at the port. At high RPMS, when the butterflies are open there would be high vacuum. Manifold vacuum is high at idle and at steady cruise speeds. When you open up the butterflies, manifold vacuum drops. In the mid-60's manifold vacuum was the proper source of dizzy vacuum.
In order to be brief, I have left a few things out. I can elaborate if anyone is interested, and you still may wish to disagree with what I have said, but that is OK because there is a lot of confusing info out there.
Personally, though, I don't plan to reconfigure my dizzy vacuum based on using a ported arrangement, although I can by moving one vacuum line on the carb over.
The dizzy hose should be connected to manifold vacuum, not ported vacuum, due to the fact that the fuel/air mixture is leaner at idle and therefore 'needs to have the fire lit' sooner. The vacuum to the dizzy provides a timing advance for normal operation at idle. Same condition occurs at steady highway speeds where you also have lean mixtures and high vacuum.
For timing at idle during tuning, disconnect the vacuum hose at the dizzy to disable the advance that otherwise NEEDS to be present!
The theories regarding ported advance were ill-thought-out when emission control was coming into awareness (1970's) and the idea was used to raise the engine temperatures by leaning out the fuel/air ratios and causing the engines to run hotter and (in a way) more emissions-free.
I have not recently read any of the referenced articles, but I believe I have read them or similar ones in the past. However, there are many articles that support my statements and if you take the time to read them, I believe you will agree with what I have just said.
For the benefit of those that may not know, ported vacuum comes basically from the carb above the butterflies and manifold vacuum comes from below the butterflies. Therefore, with ported vacuum, at idle and the butterflies closed, there would be basically NO vacuum at the port. At high RPMS, when the butterflies are open there would be high vacuum. Manifold vacuum is high at idle and at steady cruise speeds. When you open up the butterflies, manifold vacuum drops. In the mid-60's manifold vacuum was the proper source of dizzy vacuum.
In order to be brief, I have left a few things out. I can elaborate if anyone is interested, and you still may wish to disagree with what I have said, but that is OK because there is a lot of confusing info out there.
Personally, though, I don't plan to reconfigure my dizzy vacuum based on using a ported arrangement, although I can by moving one vacuum line on the carb over.
#13
I will disagree with many of the posters to state you DO need to have have vacuum at idle!
The dizzy hose should be connected to manifold vacuum, not ported vacuum, due to the fact that the fuel/air mixture is leaner at idle and therefore 'needs to have the fire lit' sooner. The vacuum to the dizzy provides a timing advance for normal operation at idle. Same condition occurs at steady highway speeds where you also have lean mixtures and high vacuum.
For timing at idle during tuning, disconnect the vacuum hose at the dizzy to disable the advance that otherwise NEEDS to be present!
The theories regarding ported advance were ill-thought-out during times when emissions were of high concern and the idea was used to raise the engine temperatures by leaning out the fuel/air ratios and causing the engines to run hotter and (in a way) more emissions-free.
I have not recently read any of the referenced articles, but I believe I have read them or similar ones in the past. However, there are many articles that support my statements and if you take the time to read them, I believe you will agree with what I have just said.
For the benefit of those that may not know, ported vacuum comes basically from the carb above the butterflies and manifold vacuum comes from below the butterflies. Therefore, with ported vacuum, at idle and the butterflies closed, there would be basically NO vacuum at the port. At high RPMS, when the butterflies are open there would be high vacuum. Manifold vacuum is high at idle and at steady cruise speeds. When you open up the butterflies, manifold vacuum drops.
In order to be brief, I have left a few things out. I can elaborate if anyone is interested, and you still may wish to disagree, with what I have said, but that is OK because there is a lot of confusing info out there.
Personally, though, I don't plan to reconfigure my dizzy vacuum based on using a ported arrangement, although I can by moving one vacuum line on the carb over.
The dizzy hose should be connected to manifold vacuum, not ported vacuum, due to the fact that the fuel/air mixture is leaner at idle and therefore 'needs to have the fire lit' sooner. The vacuum to the dizzy provides a timing advance for normal operation at idle. Same condition occurs at steady highway speeds where you also have lean mixtures and high vacuum.
For timing at idle during tuning, disconnect the vacuum hose at the dizzy to disable the advance that otherwise NEEDS to be present!
The theories regarding ported advance were ill-thought-out during times when emissions were of high concern and the idea was used to raise the engine temperatures by leaning out the fuel/air ratios and causing the engines to run hotter and (in a way) more emissions-free.
I have not recently read any of the referenced articles, but I believe I have read them or similar ones in the past. However, there are many articles that support my statements and if you take the time to read them, I believe you will agree with what I have just said.
For the benefit of those that may not know, ported vacuum comes basically from the carb above the butterflies and manifold vacuum comes from below the butterflies. Therefore, with ported vacuum, at idle and the butterflies closed, there would be basically NO vacuum at the port. At high RPMS, when the butterflies are open there would be high vacuum. Manifold vacuum is high at idle and at steady cruise speeds. When you open up the butterflies, manifold vacuum drops.
In order to be brief, I have left a few things out. I can elaborate if anyone is interested, and you still may wish to disagree, with what I have said, but that is OK because there is a lot of confusing info out there.
Personally, though, I don't plan to reconfigure my dizzy vacuum based on using a ported arrangement, although I can by moving one vacuum line on the carb over.
Greg, an engine pulls highest vacuum as it comes down on compression... anyone who has ever had vacuum powered windshield wipers will tell you this. If you are hooked to the manifold pressure to operate your Dizzy, then it will advance the dizzy when you are trying to slow down... that will cause an extreme advance situation contrary to what you are wanting the engine to do... It will cause backfiring and the RPM will be very slow to decrease. When you set your initial timing, you disconnect the hose so that there is no possibility of an improper setting due to a vacuum leak in the carb. Then you check the mechanical advance by revving the engine to make sure that the weights are engaging the advance fully by 3000-3500 rpm... If you have full manifold pressure going to the advance pot at idle you will never get the vehicle to idle properly without retarding the timing, which is not what you want to do. It is pretty simple technology!
#14
Jetcopterpilot,
I will admit the 1960's system was somewhat crude, compared to newer computer aided technology; however it won't give the problems that you say it will connected to manifold vacuum.
Vacuum advance responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions as in accelerating or decelerating.
When you disconnect the vacuum hose to the dizzy during tuning, that is to allow you to set the static advance only. The advance will be further increased when the vacuum line is reconnected, probably 10-15 degrees, so if your static advance is 12 degrees, the total timing is 25 or so degrees at idle when the vacuum line is reconnected. The timing is never retarded.
The technology seems simple, but there are many confusing articles out there that have muddied these discussions.
So far, we have not even talked about centrifugal advance which is also part of this equation and interconnected as well.
I am sure I will be hearing more about this, and I will respect your opinions, I just may not agree with them
I will admit the 1960's system was somewhat crude, compared to newer computer aided technology; however it won't give the problems that you say it will connected to manifold vacuum.
Vacuum advance responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions as in accelerating or decelerating.
When you disconnect the vacuum hose to the dizzy during tuning, that is to allow you to set the static advance only. The advance will be further increased when the vacuum line is reconnected, probably 10-15 degrees, so if your static advance is 12 degrees, the total timing is 25 or so degrees at idle when the vacuum line is reconnected. The timing is never retarded.
The technology seems simple, but there are many confusing articles out there that have muddied these discussions.
So far, we have not even talked about centrifugal advance which is also part of this equation and interconnected as well.
I am sure I will be hearing more about this, and I will respect your opinions, I just may not agree with them
#15