| [GMCnet] Timing Mark on Distributor [message #308800] |
Sun, 16 October 2016 11:31  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Someone recently posted that I had once made a timing pointer for my distributor.
It is shown here:
http://www.gmcmhphotos.com/photos/timing-marks-for-distributor/p1451.html
I found that this was very accurate for adjusting my timing.
When I lived at Santa Fe at an altitude of 7200 feet I found that I could advance the distributor anywhere and not get pinging.
At high elevations I found that advancing the distributor gave me much more power.
So I would have it at 25 degrees in the mountains but would have to lower it when traveling.
When I got down to, say 3000 feet, I would drop it to about 15 degrees. When I got to California close to sea level I would put it at 8 or 10 to prevent pinging.
This was all before I had a fuel injection controlled distributor with spark control.
I no longer use the original distributor.
Emery Stora
77 Kingsley
Frederick, CO
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| Re: [GMCnet] Timing Mark on Distributor [message #308804 is a reply to message #308800] |
Sun, 16 October 2016 12:27  |
mrgmc3
Messages: 210
Registered: September 2013
Location: W Washington
Karma: 2
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emerystora wrote on Sun, 16 October 2016 11:31
When I lived at Santa Fe at an altitude of 7200 feet I found that I could advance the distributor anywhere and not get pinging.
At high elevations I found that advancing the distributor gave me much more power.
So I would have it at 25 degrees in the mountains but would have to lower it when traveling.
When I got down to, say 3000 feet, I would drop it to about 15 degrees. When I got to California close to sea level I would put it at 8 or 10 to prevent pinging.
I assume that you are speaking of base timing, not including vacuum or centrifugal advance. Not knowing what vacuum or centrifugal advance you had it is difficult to assess what you had for total timing. I would not recommend total timing beyond about 50 degrees under any condition. Just because you can run more advance does not mean you should. We don't know what MBT (max best torque) is for the Olds V8, but probably not greater than 50 anywhere. When you run beyond MBT you lose power and economy. At lower speeds and higher loads it is generally safe to assume that you will be knock limited before MBT. But not necessarily the case at higher speeds and / or with higher octane fuels with these very low compression engines.
Chris Geils - Twin Cities / W Wa
1978 26' Kingsley w/ very few mods; PD9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, Alcoas, 54k mi
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| Re: [GMCnet] Timing Mark on Distributor [message #308808 is a reply to message #308804] |
Sun, 16 October 2016 13:46 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Somewhere around 38° maximum.
Jim Hupy.
On Oct 16, 2016 10:28 AM, "Chris Geils" wrote:
> emerystora wrote on Sun, 16 October 2016 11:31
>> When I lived at Santa Fe at an altitude of 7200 feet I found that I
> could advance the distributor anywhere and not get pinging.
>> At high elevations I found that advancing the distributor gave me much
> more power.
>> So I would have it at 25 degrees in the mountains but would have to
> lower it when traveling.
>> When I got down to, say 3000 feet, I would drop it to about 15 degrees.
> When I got to California close to sea level I would put it at 8 or 10 to
>> prevent pinging.
>
> I assume that you are speaking of base timing, not including vacuum or
> centrifugal advance. Not knowing what vacuum or centrifugal advance you
> had it
> is difficult to assess what you had for total timing. I would not
> recommend total timing beyond about 50 degrees under any condition. Just
> because
> you can run more advance does not mean you should. We don't know what MBT
> (max best torque) is for the Olds V8, but probably not greater than 50
> anywhere. When you run beyond MBT you lose power and economy. At lower
> speeds and higher loads it is generally safe to assume that you will be
> knock
> limited before MBT. But not necessarily the case at higher speeds and /
> or with higher octane fuels with these very low compression engines.
> --
> Chris Geils - Twin Cities
> 1978 26' Kingsley w/ very few mods; Headers, Progressive Dynamics 9040,
> aux trans cooler, one repaint in stock colors, R134a, Al rad, 49k mi
>
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> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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| Re: [GMCnet] Timing Mark on Distributor [message #308817 is a reply to message #308800] |
Sun, 16 October 2016 16:32 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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emerystora wrote on Sun, 16 October 2016 12:31Someone recently posted that I had once made a timing pointer for my distributor.
It is shown here:
http://www.gmcmhphotos.com/photos/timing-marks-for-distributor/p1451.html
I found that this was very accurate for adjusting my timing.
When I lived at Santa Fe at an altitude of 7200 feet I found that I could advance the distributor anywhere and not get pinging.
At high elevations I found that advancing the distributor gave me much more power.
So I would have it at 25 degrees in the mountains but would have to lower it when traveling.
When I got down to, say 3000 feet, I would drop it to about 15 degrees. When I got to California close to sea level I would put it at 8 or 10 to prevent pinging.
This was all before I had a fuel injection controlled distributor with spark control.
I no longer use the original distributor.
Emery Stora
77 Kingsley
Frederick, CO
Emery,
Thanks, I knew I had seen it and thought it was a marvelous idea. I do plan to copy that if we are ever over 5KMSL for more than mere moments.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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