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Re: vacumm guage
[Re: Tadams]
#1121778
11/26/11 05:35 PM
11/26/11 05:35 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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Quote:
The timing mark is about 2 inches of the mark My question is the vacumm gauge goes from 19 to 21 rapidly.What do I check now?
(1) clarify that (2) there's a prob somewhere (if not a radical cam). (3) If you experiment w idle mixture/speed can you get it to get steadier?. what idle speed and is that Formula S cam a lumpy one EDIT (re)read it & 19-21 would have to be a smooth cam. I'd do a compression/leakdown tests for starters after idle mixture and short each cyl to ground (cyl balance) & note what the needle does. Sounds like one cyl (or more) is a fair amt weaker than the others/not pulling it's load when it fires making it dip to 19 for that split second that it is firing
Last edited by RapidRobert; 11/26/11 05:50 PM.
live every 24 hour block of time like it's your last day on earth
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Re: vacumm guage
[Re: Tadams]
#1121779
11/26/11 06:09 PM
11/26/11 06:09 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
I adjusted the timing with a vacumm guage as was recommended. The timing mark is about 2 inches of the mark but it starts and idles good. My question is the vacumm gauge goes from 19 to 21 rapidly. When you rev it up it smooth out.
What do I check now?
This a stock 273 commando in my 65 Barracuda Formula S.
Thanks for your help.
On your 273 is that a mech cam... check your lash
adjustment
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Re: vacumm guage
[Re: MR_P_BODY]
#1121780
11/26/11 06:47 PM
11/26/11 06:47 PM
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Joined: Sep 2011
Posts: 239
North Carolina
Tadams
OP
enthusiast
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OP
enthusiast
Joined: Sep 2011
Posts: 239
North Carolina
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Thanks every one for your help. It is a stock engine and has a stock cam.I think with the 4 barrell this car should have dome pistons and I think the cam is a little different from the regular engine. Idle speed was 800 RPM and the high the rpm the smoother it was. I'll adjust the valves next week and see if that helps. The carb was just rebuilt and I think is set properly.
Last edited by Tadams; 11/26/11 06:48 PM.
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Re: vacumm guage
[Re: Tadams]
#1121781
11/26/11 08:53 PM
11/26/11 08:53 PM
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Joined: May 2003
Posts: 15,487
Florida
scratchnfotraction
I Live Here
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I Live Here
Joined: May 2003
Posts: 15,487
Florida
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vac gauge fluctuating bouncing could be a bad valve/weak cyl. rockers out of adjustment timeing chain sloppy vac leak for starters,a comp check and leak down wet and dry are in order. snake oil test.... hold a dollor bill at the tail pipe and see if it sux it in then pops it back out while watching the vac gauge bounce in time with the doller poping 
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Re: vacumm guage
[Re: RapidRobert]
#1121784
11/26/11 10:59 PM
11/26/11 10:59 PM
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Joined: Aug 2003
Posts: 12,291
Kent, Wa
340SHORTY
Truck Nut
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Truck Nut
Joined: Aug 2003
Posts: 12,291
Kent, Wa
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2" off,,, are you useing # 1 plug or did you goof up and use #2 plug to hook the timing light up to???
I am truckless..
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Re: vacumm guage
[Re: Tadams]
#1121787
11/27/11 01:41 AM
11/27/11 01:41 AM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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2" on the dampener is ~32 deg and that is just to the left edge of the tab? or is that in to the zero in the middle of the tab. Something still ain't right EDIT I suspect the too high initial is possibly causing the unsteady needle EDIT on the initial you got max vac in drive then backed off 1 in hg all the while reducing the idle speed correct?
Last edited by RapidRobert; 11/27/11 03:04 AM.
live every 24 hour block of time like it's your last day on earth
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Re: vacumm guage
[Re: Tadams]
#1121789
11/27/11 10:51 AM
11/27/11 10:51 AM
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Joined: Apr 2010
Posts: 4,154
bethlehem pa
mikemee1331
master
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master
Joined: Apr 2010
Posts: 4,154
bethlehem pa
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Quote:
My wife said I need to make a new friend locally who works on cars, sounds like a plan.
 sound advice but make sure you stay involved (hands-on)  join a local mopar club. for someone that isn't that mechanically inclined, all the advice (while usually good) can make your head spin!
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Re: vacumm guage
[Re: Tadams]
#1121793
11/27/11 01:54 PM
11/27/11 01:54 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Hi Mike,
Im learning, for sure.
Dont get too hung up on the fact that the vac gauge
jumps some at lower rpm... the slower the rpm it
has more time to see the pulse... at higher rpm they
are blended together.... plus the LSA on that cam
is tighter which has more over lap and more over lap
has pulses
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Re: vacumm guage
[Re: MR_P_BODY]
#1121794
11/27/11 02:41 PM
11/27/11 02:41 PM
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Joined: Apr 2010
Posts: 4,154
bethlehem pa
mikemee1331
master
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master
Joined: Apr 2010
Posts: 4,154
bethlehem pa
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Quote:
Quote:
Hi Mike,
Im learning, for sure.
Dont get too hung up on the fact that the vac gauge
jumps some at lower rpm... the slower the rpm it
has more time to see the pulse... at higher rpm they
are blended together.... plus the LSA on that cam
is tighter which has more over lap and more over lap
has pulses
BINGO
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Re: vacumm guage
[Re: mikemee1331]
#1121795
11/27/11 07:23 PM
11/27/11 07:23 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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I'd recheck all the basics: adj valves (.013 in .021" ex). Timing chain (rockover). slipped dampener w the piston stop tool. marks at 10BTDC #1 compression & time dist at that initial (which is stock for all 4bbl and 2bbl w auto and or power pack). 2bbl WO them is 5. Plus compression test (leakdown too if you have a gauge setup)
live every 24 hour block of time like it's your last day on earth
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