One tooth off?

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Old Apr 14, 2024 | 04:10 PM
  #1  
72455's Avatar
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1972 U code Supreme
 
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From: Chesapeake, VA
One tooth off?

So after replacing the intake manifold gaskets on my '72 Supreme, my buddy and I set #1 cylinder to TDC and dropped the distributor in. I noticed that after we dialed it in, the distributor was in the 1 o'clock-7o'clock position instead of the 12-6 position like before. Timing at idle is around 12 deg and around 30-32 at 2500 rpm. Once it reaches that point, it won't advance anymore. She idles good and holds steady through the rpm range with no issues, but there is a problem on the low end.

She's a little flat on takeoff when I nail it. I left work today and jumped on it and it popped once through the carb then smoothed out, but seemed kinda lazy getting up to speed. Now, the top end is a different story. Definitely more snappy, and I seem to be getting better mileage.

I'm running a DUI HEI street/strip unit, and it has done well since I bought the car 6 years ago. I will, however, be replacing the cap, wires and coil this week.

I cant rotate the distributor anymore to the left because the advance canister is hitting the firewall. Once I replace the wires, cap, rotor and coil this week, will that help with the takeoff, or do I need to move the distributor 1 tooth to the left?
Old Apr 14, 2024 | 04:38 PM
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From: Tracy Ca
If you think you are one tooth off, I think you need to re stab the distributor. Then you will also be able to move it so it don't hit the fire wall.
Old Apr 14, 2024 | 05:16 PM
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1972 U code Supreme
 
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Originally Posted by 442Harv
If you think you are one tooth off, I think you need to re stab the distributor. Then you will also be able to move it so it don't hit the fire wall.
And I wouldn't have to reset TDC, correct? Just move the distributor?
Old Apr 14, 2024 | 07:26 PM
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If you are referring to finding TDC on the balancer or the #1 piston, then no. But any time you remove and reinstall the distributor, you have to reset the initial timing.
Old Apr 14, 2024 | 07:36 PM
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1972 U code Supreme
 
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Originally Posted by Fun71
If you are referring to finding TDC on the balancer or the #1 piston, then no. But any time you remove and reinstall the distributor, you have to reset the initial timing.
Gotcha. Does it sound like my symptoms necessitate adjusting the timing, or will the new wires and cap help?
Old Apr 14, 2024 | 07:41 PM
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If the initial and total timing are where they should be, then restabbing the distributor and resetting the timing will result in everything being the same as it is now, just the distributor housing moved a bit. It won’t have any affect on how the engine operates since the timing will be exactly the same.
Old Apr 15, 2024 | 06:36 AM
  #7  
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If the vac advance is hitting the fire wall, and keeping you from getting the right timing, you may want to move. Check your initial timing and total, see if it is correct? Look for total between 34-38, if you can't get it move it. Like the other post said, if this numbers are correct, you won't change much, just the location look.
Old Apr 15, 2024 | 07:19 AM
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1972 U code Supreme
 
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Originally Posted by 442Harv
If the vac advance is hitting the fire wall, and keeping you from getting the right timing, you may want to move. Check your initial timing and total, see if it is correct? Look for total between 34-38, if you can't get it move it. Like the other post said, if this numbers are correct, you won't change much, just the location look.
34-38 at idle or at 2500 rpm, and that's with the vacuum advance connected?
Old Apr 15, 2024 | 07:30 AM
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The vacuum advance hitting the firewall even if the the timing correct isn't good. Take the time to make it correct.
Old Apr 15, 2024 | 09:05 AM
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Originally Posted by 72455
34-38 at idle or at 2500 rpm, and that's with the vacuum advance connected?
At 2500 (or higher) with vacuum advance disconnected.
Old Apr 15, 2024 | 09:17 AM
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Originally Posted by 72455
34-38 at idle or at 2500 rpm, and that's with the vacuum advance connected?
At the rpm timing stops advancing with vacuum disconnected.
Old Apr 15, 2024 | 09:59 AM
  #12  
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1972 U code Supreme
 
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Originally Posted by oldcutlass
At the rpm timing stops advancing with vacuum disconnected.
So should it be connected then?
Old Apr 15, 2024 | 10:12 AM
  #13  
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Originally Posted by oldcutlass
At the rpm timing stops advancing with vacuum disconnected.
Originally Posted by 72455
So should it be connected then?
Old Apr 15, 2024 | 11:05 AM
  #14  
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Connect the vacuum advance after completing all your timing adjustments.
Old Apr 15, 2024 | 12:39 PM
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Distributor installation/alignment & timing are detailed in the CSM. For your reading pleasure I've attached Timing 101.


Attached Files
File Type: pdf
Timing101.pdf (108.7 KB, 9 views)
Old Apr 18, 2024 | 11:42 AM
  #16  
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1972 U code Supreme
 
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Got everything swapped out today and dialed in the timing after moving the distributor one tooth. She's on point now

Old Apr 18, 2024 | 12:05 PM
  #17  
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Glad to hear, looks nicely detailed!
Old Apr 18, 2024 | 12:08 PM
  #18  
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Running On Empty
 
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Dave - I'd make an adjustment to correct your throttle/accelerator cable. That cable is most likely incorrect for your application - appears too short or perhaps of the incorrect material (I don't know).

The throttle/accelerator cable should be entering the carburetor stand-off bracket from a straight forward head-on position. Your cable is significantly out of alignment. So much so, it's bending the stand-off and you can visibly see the grommet has substantial tension/force being applied to it. This should be corrected.
Old Apr 20, 2024 | 06:20 PM
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I am happy to confirm the timing is corrected and it is no longer "lazy". What a ride!
Every time we stopped, someone complimented Dave's car.
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