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Discussion Starter · #1 ·
What exactly makes it adjustable? I know this is a real stupid question but my "lack of" experience is more IN the engine than out. I have a Pertronix flamethrower and they say i have one of these adjustabel canisters already. So, i want to find out how you adjust them.
Thanks,

Gary
 

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you adjust it by sticking a 3/32 allan in the vacuum port of the can. Right, clockwise turns provide more advance, left, counterclockwise take advance out. Remember that vacuum advance only works at part throttle. Its NOT for performance. Your can has no vacuum at idle or full throttle.

All vacuum advance does is give you a better, cleaner burn by sparking your charge sooner when you're just putting down the highway or around town.

If your plugs are clean, your mileage is about right, and you're not spark-knocking at part throttle (good test is goign uphill at a moderate speed in your tallest gear) then don't touch it-

k
 

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Discussion Starter · #3 · (Edited)
killer, my mileage is horrific for what i have and i do have a little knock or ping......sometimes at part throttle. Go figure....lol. I haven't tried to figure out the exact number for mileage, but a good guess would be 10 or less. I know my 850 Demon mech. sec. is a good source of guzzling though. But that much?

Also, i hear alot of people on here say 700-800 Rpm idle!?! Try 1800 for me, that is were it runs best without detonation. I tried mine at like 900-1000 at one time and it was as quiet as i've heard and was a real slug. Almost sounded like it wasn't running.
 

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1800 is too high, something is wrong.

First thing you need to do is check for a vacuum leak on your motor. Get a can of carburetor cleaner and spray slowly on your intake gaskets (right where the runners mee the heads). If the idle improves you've found your leak. Other places to check are all the way around the base of the carburetor, go slow. Spray the linkages of the carb too, sometimes they are loose and leak through teh body.

Always start with a baseline. paint a mark on your distributor and see where it is right now so you can tell what you're doing and which way you're going. Clockwise is retard, counterclockwise is advance (and you have no idea how many people have it backwards!!!)

you have to read your plugs. Take them out and see what color they are, be thorough, notice the little things.

Are you sure sure sure that your choke is off. Double check, make sure its in its proper position!

My thought is that you probably have too high of an idle, you've got probably too much initial andvance and your mechanical is coming in super slow. Are you sure your vacuum can is hooked up to the PORTED vacuum sorce and not the full manifold.... it makes a big difference!

K
 

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Discussion Starter · #5 ·
killerformula said:
1800 is too high, something is wrong.

First thing you need to do is check for a vacuum leak on your motor. Get a can of carburetor cleaner and spray slowly on your intake gaskets (right where the runners mee the heads). If the idle improves you've found your leak. Other places to check are all the way around the base of the carburetor, go slow. Spray the linkages of the carb too, sometimes they are loose and leak through teh body.

Always start with a baseline. paint a mark on your distributor and see where it is right now so you can tell what you're doing and which way you're going. Clockwise is retard, counterclockwise is advance (and you have no idea how many people have it backwards!!!)

you have to read your plugs. Take them out and see what color they are, be thorough, notice the little things.

Are you sure sure sure that your choke is off. Double check, make sure its in its proper position!

My thought is that you probably have too high of an idle, you've got probably too much initial andvance and your mechanical is coming in super slow. Are you sure your vacuum can is hooked up to the PORTED vacuum sorce and not the full manifold.... it makes a big difference!


K
I have checked for vacuum leaks like that a couple of times and found nothing. I have NO choke on the carb. I did pull my plugs awhile back and they seemed good-caramel to white. I also think it is too much initial but if i take it away it takes alot with it. And yes, i do have it hooked up to a manifold source. Sorry for the short precise answers, just trying to keep up.....lol
 

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Discussion Starter · #7 ·
killerformula said:
ok, take it off that manifold source, its messing everything up!

Tell me again what motor you're running, compression, head type, cam, CID etc

K
It is a 455 Olds about 9.7-1, stock C heads. Comp Cams XE 274. It is bored .030 sowhatever that makes ontop of the 455...lol
 

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Are going to get into the old "port or manifold vacuum" discussion?

The last time, we decided full manifold vacuum.

MI2600 said:
Are we going to get into the old "port or manifold vacuum" discussion?

The last time, we decided full manifold vacuum.
 

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Discussion Starter · #9 ·
Well, i just hooked it toported on the carb and it made a huge difference in RPM. Now it idles around 1000-1100. But, when it idles there it acts like it is barely running. Like it want to die.
 

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G-

Killer has said a mouthful there, he is right on the money. Having it plugged to full manifold is maxing out your timing at cruise. What is your total with vacuum? You may just need to back off a bit at the vacuum can. I don't know what yours should be since it is an Olds, but you need to find out what your max timing with vacuum. Ported and manifold vacuum requires different tuning, and using which one depends on the engine combo. As a general rule, the more radical your combo, go with manifold vacuum source, and tune accordingly.

I have Pertronix setup in my HEI. It comes with a 23 degrees mechanical, and I set my initial to 15, for a total of 38 (which mine likes). I then set my vacuum timing total to equal 52 degrees with it plugged in at 3000 rpm. I use the lightest springs, the brass/copper ones, so all of my timing is in by 2800-3000.

Hope this helps.
 

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Discussion Starter · #11 ·
OK,but what else can i do to keep it from acting like it is going to die at 1100RPM idling? It is the same thing whether it is in the ported or manifold. It still want to be at 1800RPM. Anything i do to get it to idle better is going to result in more RPM at idle.
 

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gpeak said:
Also, i hear alot of people on here say 700-800 Rpm idle!?!

I tried mine at like 900-1000 at one time and it was as quiet as i've heard and was a real slug. Almost sounded like it wasn't running.
You need to set your timing to specs, or somewhat specs, then set your idle. If it is a dog down low, you may have other problems. What type of carb are you running?
 

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Discussion Starter · #15 ·
Well thank you wildman. You are only the 3rd person who thinks my carb isn't too big. That's why i try to get that out of the way....lol. Yes i have adjusted my idle circuit with a vacuum gauge. I just don't understand how to get it to "idle" right at the appropriate RPM. It "runs" nicely at 1800 but that is too high for idleing. I have never had this problem before an any of these engines. It just doesn't make sense.

OK, thanks again all!
 

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G-

Do you have your floats set properly? Are you setting your idle circuits with the rpms real low - 600-700 rpm for the best vacuum, then resetting the idle up to 800-900? While doing all of this, is the engine up to operating temp and the choke is fully off? Is your fuel pump up to par? How much vacuum at 800-900 rpm with idle circuits adjusted properly?
 

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Discussion Starter · #17 ·
I have been messing with this for awhile now. It won't idle by itself in gear with less than 1100RPM. So doing it @ 6-700 is pretty hard. I wish i had another tach to just see. But when it's at 1000RPM in park,it just acts like there is nothing there and it's going to die.

I give up!

For now!
 

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Discussion Starter · #19 ·
jimfulco said:
Do those carbs have an idle or throttle-opening adjustment on the secondary side?

It just opens the plate on the adjustment. I also was told that if my mechanical is retarded..lol... by 1200RPM it will also do this.

How would i go about checking that?
 
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