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https://slantsix.org/forum/viewtopic.php?t=50214		 Page 4 of 5
Author:  kielbasa [ Tue Nov 06, 2012 11:44 pm ]
Post subject: 
Actually tonight on thr steepest hill i travel on weekly i was getting pinging. And i noticed temp gauge reads hotter then it usually doea even on a cold night. Would turning the vacuum pod counter clockwise two turns fix this? I'm 3 turns out right now
Author:  Aggressive Ted [ Wed Nov 07, 2012 6:17 am ]
Post subject: 
It may, but lowering your initial down to 6 degrees would be my choice to fix the problem if your still trying to run it at 12 degrees.

Where you pushing it? If you where and say vacuum was around 3" to 5" then back off on initial because the vacuum pod isn't even engaged much or at all.

You need to have a vacuum gauge in your car to monitor where the ping happens to know what to adjust. I am just making a guess that you may be at the low end of the vacuum scale, not experiencing it my self or watching the gauge......
Author:  kielbasa [ Wed Nov 07, 2012 9:36 am ]
Post subject: 
Its happening when i get on it on the hill when a good load is on it.
Author:  Aggressive Ted [ Wed Nov 07, 2012 12:00 pm ]
Post subject: 
That would be best fixed by backing off on the initial timing......
What do you have it set at now???

How soon you re-plot your new figures?
Author:  kielbasa [ Wed Nov 07, 2012 1:52 pm ]
Post subject: 
I dropped initial down to 6, reset idle back to 725 and getting 2" ported vacuum. I mighy get a chance to replot today
Author:  Aggressive Ted [ Wed Nov 07, 2012 3:29 pm ]
Post subject: 
Very odd your seeing any ported vacuum. Need to lower the idle (throttle blades) so the transition slot closes more...then get some idle back with your mixture screw. The ported line should read zero at 750 rpm.
Author:  kielbasa [ Wed Nov 07, 2012 6:11 pm ]
Post subject: 
Second Run

MECHANICAL ADVANCE

RPM...........Advance.........Ported Vacuum
725............6...................>1"
1000..........8-6=2............17"
1500..........20-6=14........18"
2000..........22-6=16........21"
2500..........24-6=18........21"
3000..........27-6=21........21"
max...........27-6=21........21"

VACUUM ADVANCE

RPM...........Advance.........Manifold Vacuum
725............6.....................18"
1000..........30-2=28.........19"
1500..........42-14=28.......20"
2000..........45-16=29.......19"
2500..........48-18=30.......20"
3000..........50-21=29.......20"
max...........50-21=29.......20"

HAND PUMP

Vacuum..........Advance
0"...................6
1"...................6
2"..................."
3"..................."
4"..................."
5"..................."
6"..................."
7"..................."
8"...................7-6=1
9"...................9-6=3
10".................12-6=6
11".................16-6=10
12".................19-6=13
13".................21-6=15
14".................24-6=18
15".................27-6=21
max................27-6=21
Author:  kielbasa [ Thu Nov 08, 2012 1:45 pm ]
Post subject: 
Do these numbers look better vs first run?
Author:  Aggressive Ted [ Thu Nov 08, 2012 2:05 pm ]
Post subject: 
Much better!

How does it feel? and drive?
Author:  kielbasa [ Thu Nov 08, 2012 2:11 pm ]
Post subject: 
Seems to be okay, same as 12initial, havent been over that hill that made me ping yet.
Author:  Aggressive Ted [ Thu Nov 08, 2012 2:21 pm ]
Post subject: 
I will send you a spread sheet to fill out that plots a nice chart. This used to be in the recurve section under Engine FAQ. You can play with different initial settings and see the results.
Author:  kielbasa [ Thu Nov 08, 2012 2:58 pm ]
Post subject: 
thanks!

my vacuum advance @RPM is always maxed at 21, i noticed yours had a gradual increase on that section.

what about dialing in everything for my cruising speed, i calculated my RPM at 65mph is 2568
Author:  Aggressive Ted [ Thu Nov 08, 2012 5:47 pm ]
Post subject: 
Quote:
my vacuum advance @RPM is always maxed at 21, i noticed yours had a gradual increase on that section.
That is at the timed port.....The reason is, during driving it fluctuates depending on how hard your pushing on the gas. If your going up a hill or not..........going up a hill the vacuum advance shuts off as it goes below 8" of vacuum at 5 turns out.
Quote:
what about dialing in everything for my cruising speed, i calculated my RPM at 65mph is 2568
That is fine if all you do is drive on the freeway. Out here max cruise on the back roads is 50 mph or 2000 rpm. 60 Mph on the freeway is 2500 rpm with 26" tall tires. I have the mechanical kicking in early on the back roads for a punchy feel and on the freeway the advance kicks into overdrive.
Author:  kielbasa [ Thu Nov 08, 2012 6:04 pm ]
Post subject: 
Well i do a lot of 45/50mph driving, then freeway i drive 65

1778/1975rpm is my street driving, is my setup set for this or do i need to do some adjusting somewhere
Author:  SlantSixDan [ Thu Nov 08, 2012 6:17 pm ]
Post subject: 
Quote:
Very odd your seeing any ported vacuum
Not odd at all. This is why the instructions for setting the base timing start with

1. Disconnect vacuum advance hose and plug carburetor nipple

Think about it: if there weren't supposed to be any vacuum at the spark advance port at idle, why would that first step be necessary?

Each and every carburetor model is a little bit different with respect to its idle calibration, spark advance port location relative to the throttle plate(s), etc. When everything is as the factory configured it for any given model/engine/transmission/emissions package/year/market, then you can achieve the specified curb idle speed and base ignition timing with near-zero vacuum at the spark advance port (2° counts as "near zero"). Start making changes, and that interrelationship goes out the window. Remember, idle speed is affected by ignition timing, too, not just throttle plate position. If you put in a bunch of base spark advance (12°, for example), you're going to have to close the throttle plates almost completely to achieve a reasonably slow curb idle speed. Vacuum advance won't kick in until later in the throttle travel. If you take out base ignition timing, on the other hand, your idle speed will want to drop and you'll have to open up the throttle to get it back up where you want it, so the spark advance port will register more vacuum. That's on carburetors without an adjustable idle air bypass -- those started seeing production around 1969.
Quote:
then get some idle back with your mixture screw.
For any given reasonable timing and crackscrew setting, idle speed will be at maximum when the idle mixture screw is set correctly. However, the idle mixture screw is not an appropriate thing to adjust the idle speed with.
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