Re: amount of vacum @idle ?
[Re: mopar0723]
#912981
01/24/11 06:31 PM
01/24/11 06:31 PM
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Joined: Oct 2003
Posts: 996 Queens, New York
Harley
super stock
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super stock
Joined: Oct 2003
Posts: 996
Queens, New York
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Quote:
1970 440+6 engine bored 030 stock spec cam 292 duration 590 lift how much vacum should I have at idle say 800 rpm /vacum gauge hooked to rear of intake.
292/590 lift is far from stock. If that is the cam you are running, i would think more like 12 to 14 inches of vacum.
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Re: amount of vacum @idle ?
[Re: mopar0723]
#912983
01/24/11 06:45 PM
01/24/11 06:45 PM
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Joined: Oct 2007
Posts: 3,933 Oregon
hooziewhatsit
master
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master
Joined: Oct 2007
Posts: 3,933
Oregon
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What's your initial timing at?
If you ever find yourself in a fair fight, your tactics suck.
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Re: amount of vacum @idle ?
[Re: mopar0723]
#912985
01/24/11 07:09 PM
01/24/11 07:09 PM
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Joined: Jan 2003
Posts: 2,022 s. e. pa.
calrobb2000
top fuel
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top fuel
Joined: Jan 2003
Posts: 2,022
s. e. pa.
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hi 9 in with that cam no more prob? idle speed for a six pack is 900 rpm ! what is your actual comp ratio or cranking compression psi ??
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Re: amount of vacum @idle ?
[Re: mopar0723]
#912989
01/24/11 08:06 PM
01/24/11 08:06 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Quote:
if set @ 800 fluctuates between 780 - 810 normal ?
Actually yes as I forgot that you have a cam. It MAY need a higher idle speed to stabilize. EDIT after (re) reading I dont think it's a dist prob. I would set the (initial)timing via the vac gauge method then shorten the slots to get 36-38 total then play w the springs (more on that later) then dial in the vac adv (more on that later). You will need to find the idle speed for that cam that is stable (maybe higher than 800) and I am not a 6 pack guy but they (the carbs) MAY or may not need mods for a wild cam
Last edited by RapidRobert; 01/24/11 08:19 PM.
live every 24 hour block of time like it's your last day on earth
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Re: amount of vacum @idle ?
[Re: mopar0723]
#912991
01/24/11 09:02 PM
01/24/11 09:02 PM
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Joined: Feb 2005
Posts: 4,333 Prospect, PA
BSB67
master
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master
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Prospect, PA
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Quote:
1970 440+6 engine bored 030 stock spec cam 292 duration 590 lift how much vacum should I have at idle say 800 rpm /vacum gauge hooked to rear of intake.
Your statements regarding the cam do not make sense. There is no stock cam with specs anywhere near what you've posted.
Is it possible that it is a Mopar 292/509 cam?
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Re: amount of vacum @idle ?
[Re: mopar0723]
#912994
01/24/11 09:22 PM
01/24/11 09:22 PM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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Quote:
Yea I can not set car @ 900 rpm, where it probably should be, it is a 4 speed. as soon as I turn idle up and get to about 870-880 it just takes off to the 1050-1150 as stated above and stays there, then have to loosen idle screw to get it back down, only does this if vac adv hose hooked up,won't do this if I plug, but I want it hooked up and it all to work the way it is supposed to. I do not know what else to try before buying a new distibutor.
get a vacuum pump gauge on the vacuum advance. disconnect the hose at the carb, and plug the gauge in there. take off the distributor cap, and see at what level of vacuum the plate starts to rotate. sounds like it is set very low, and is advancing as soon as you hit the 800 rpm range or so.
i don't know about the older distributors, but with the newer ones you can stick a small allen wrench in the hole on the vacuum advance canister where the hose plugs into. with that, you can loosen or tighten the springs on the vacuum advance, so it comes in with more/less vacuum, as needed by your situation.
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Re: amount of vacum @idle ?
[Re: mopar0723]
#912995
01/24/11 09:30 PM
01/24/11 09:30 PM
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Joined: Jan 2003
Posts: 1,793 Windsor, ON, Canada
Diplomat360
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,793
Windsor, ON, Canada
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Quote:
Yea I can not set car @ 900 rpm, where it probably should be, it is a 4 speed. as soon as I turn idle up and get to about 870-880 it just takes off to the 1050-1150 as stated above and stays there, then have to loosen idle screw to get it back down, only does this if vac adv hose hooked up,won't do this if I plug, but I want it hooked up and it all to work the way it is supposed to. I do not know what else to try before buying a new distibutor.
To me that sounds like a vacuum can adjusted with way too little tension...that means it'll come on quicker...you may be getting some interaction between the vac can and the distributor mechanical advance. Namely, the vac can kicks in...the idle speed jumps up, the dist goes into the mech advance curve...etc....the dead giveaways is that this does not happen with the vac can disconnected.
Toss in an alan wrench into the nipple and tighten it up...so that it comes on at a higher vacuum signal.
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Re: amount of vacum @idle ?
[Re: mopar0723]
#912997
01/24/11 09:50 PM
01/24/11 09:50 PM
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Joined: Feb 2005
Posts: 4,333 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
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Prospect, PA
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Quote:
yes you Are right I typed in the wrong numbers that is the cam in the motor 292/509
This is a big cam. Add the six pac, low compression and 10 degrees initial timing and 8" sounds right. Although I have not had this combination myself.
Personnally, I would skip the vacuum advance for now, it is just one more variable. You can put it back later.
Get your initial timing to be 20 degrees and steady (not advancing) to at least 1200 rpm. Then check for vacuum leaks at the carbs and intake manifold. Then use a vacuum gauge to adjust each carb.
That will get you started.
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