Vacuum advance ?????

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Re: Vacuum advance ?????

Postby monza355 » Thu Jul 22, 2010 5:57 pm

Well here is a question no one seems to ask. How much mechanical advance does the distributor have? Do you find out your total advance then subtract the initial advance? If you have 18 initial and 38 total, you have 20 in mechanical?
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Re: Vacuum advance ?????

Postby 72 SS PNL » Thu Jul 22, 2010 6:49 pm

vacuum needs to be disconnected , then total - initial = mech
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Re: Vacuum advance ?????

Postby cjbiagi » Thu Jul 22, 2010 7:17 pm

Yes, you are correct in your example. If you have 38 total with 18 initial that means you have 20 mechanical. Vacuum advance is not part of that equation, whatever you have for vacuum advance is above and beyond.
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Re: Vacuum advance ?????

Postby marco_1978_spyder » Mon Aug 16, 2010 9:56 am

Read this....

Best and easist explanation to understand...

http://www.lbfun.com/warehouse/tech_inf ... lained.pdf
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Re: Vacuum advance ?????

Postby marco_1978_spyder » Mon Aug 16, 2010 10:44 pm

I switched over to Ported today....and you know what? I like how the car runs, even better than with the manifold vac..
I did notice however, that the idle cooling of manifold vac was gone, and the temp of the engine would continually creep upwards if left to sit at idle.

It qould be cool to be able to switch from inside the car... Switch to manifold vac when stuck in slow / stopped traffic, and back to ported when the roads clear up..
1978 Monza Spyder V8 4speed, posi
1978 Sunbird Formula V6, 5 Speed, Hatchback
1980 Sunbird Hatchback 4cyl, 4spd.
2006 Chevrolet Aveo 5 speed Hatchback
Yes, you can refer to me as Mark
Please visit my blog... http://chevymonza.blogspot.com/ Follow if you like!
Featuring special guests; Carl Beraytor and Ray D'atore

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Re: Vacuum advance ?????

Postby cjbiagi » Mon Aug 16, 2010 11:16 pm

Actually you could probably do that with a temperature controlled vacuum switch.
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Re: Vacuum advance ?????

Postby Len » Tue Aug 17, 2010 1:05 am

Or as Gm reefers to it a tvs .In there vac diagrams .
Or another easy solution but dam hot is turn the heat on hot and blower motor on high it is an extra rad lol
been there and done that to cool a hot motor a few times . Not comfy but works . Unless you have bypassed it ?
I am a firm believer that not only does the heater core provide heat but also is a solid part of the cooling system . the heat it provides is just a byproduct of the cooling that it provides. Don't know if any body has noticed but in these car the blower motor is never really off with the car running ?
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Re: Vacuum advance ?????

Postby marco_1978_spyder » Tue Aug 17, 2010 5:46 pm

I've noticed that len, but thats more for eliminating the build up of potentially deadly exhaust gasses inside the interior.

The 'heater on high' trick has very rarely helped my situations of overheating.
But It does help overall by adding that much more fluid capacity to the system. I don't think that bypassing it should be a big issue as long as extra radiator capacity is added.
1978 Monza Spyder V8 4speed, posi
1978 Sunbird Formula V6, 5 Speed, Hatchback
1980 Sunbird Hatchback 4cyl, 4spd.
2006 Chevrolet Aveo 5 speed Hatchback
Yes, you can refer to me as Mark
Please visit my blog... http://chevymonza.blogspot.com/ Follow if you like!
Featuring special guests; Carl Beraytor and Ray D'atore

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Re: Vacuum advance ?????

Postby Len » Wed Aug 18, 2010 1:37 am

Interesting , never thought of it that way but it seems to me that if the hot air door is adjusted properly there is no hot air flow to the pass compartment from the blower in the cold setting . (summer) And the floor vents are opened for cooling the int on a non ac car . and visa versa in cold weather, But of course that is in a perfect world . I have not verified this but it makes sense . Cant see why you would want to pump hot air in the cold setting unless you trying to dissipate heat.
It has got me to wondering where the the hot air does go in the summer setting.
Never did understand if your trying to cool something why would you blow hot air at it ??? lol
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Re: Vacuum advance ?????

Postby Rickey » Wed Oct 06, 2010 9:50 pm

Have you ever noticed that the factory, early 140 c.i. had a switch that prevented vacuum advance till out of first gear? May have been a four speed only thing.
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