What is vacuum advance

bad68coupe

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Jul 18, 2006

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#1

• Dec 3, 2006

• #1

what is vaccum advance and how do i know if i have it

 

65ShelbyClone

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#2

• Dec 3, 2006

• #2

Look at your distributor. If there is a little canister type thing in the side of it with a vacuum line hooked to it, you have vacuum advance. About 90% of the carbureted street cars out there have it.

 

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65ragTop

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Mar 24, 2006

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If you have something that liiks like this.

Sorry for the ugly engine bay, I have a long way to go on this car, I just started with it and am just trying to make it driveable right now....

 

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65ShelbyClone

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#4

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65ragTop said:

Sorry for the ugly engine bay, I have a long way to go on this car, I just started with it and am just trying to make it driveable right now....

Click to expand...

Yeah, but you can drive it, right? That's all that matters.

 

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65ragTop

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65ShelbyClone said:

Yeah, but you can drive it, right? That's all that matters.

Click to expand...

Yes I can drive it.

 

bad68coupe

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#6

• Dec 3, 2006

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i am building a new engine, so i don't know which one to go with. whats the difference between the two? is one better than the other?

 

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86bluecobra

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Dec 20, 2004

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#7

• Dec 3, 2006

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Vaccuum advance usally helps with fuel economy. You can plug it and set the dizzy to intial that you want and forget the vaccuum if you want.

 

bad68coupe

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#8

• Dec 4, 2006

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86bluecobra said:

Vaccuum advance usally helps with fuel economy. You can plug it and set the dizzy to intial that you want and forget the vaccuum if you want.

Click to expand...

not completely sure what you mean.

 

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mustangman70

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#9

• Dec 4, 2006

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As the vacuum increases it slowly advances the timing troughout the curve...

 

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351carlo

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Dec 4, 2006

#10

• Dec 4, 2006

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Strictly for fuel economy. I don't want to hear anything else, except fuel economy.

The idea is it pulls timing advance as vacuum is increased. Want to see where your engine pulls vacuum? Hook up a vacuum gauge and drive the car. If you're anything like me, you'll be lucky to see much vacuum at all while driving, except when popping it in neutral after a hard 3 gear pull.....

Under wide open throttle you will not see any vacuum, and the distributor will advance based upon the mechanical advance mechanism (Weights and springs inside distributor).

If you're building a cruiser, stock style rebuild, or a car you plan to drive for long distances, go with the vacuum advance. If it's a street/strip car, a car with good hp where you need to know the timing at all times, or a car that is just for show... I like a mechanical advance only distributor. One less vacuum line to worry about.

 

65ShelbyClone

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#11

• Dec 4, 2006

• #11

You also have to be sure any replacement carburetors like Holleys have a ported vacuum connection. Mine didn't(Ebay special) and I had to trade the metering block with one of my others that had ported vacuum.

 

bad68coupe

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#12

• Dec 5, 2006

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will my edelbrock 1406 work?

 

Max Power

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Jul 31, 2003

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St Paul

Dec 5, 2006

#13

• Dec 5, 2006

• #13

It should.

While ported timing and vacuum advance are mainly for economy and emissions, for street driving I think it is better. It not only takes engine speed as a factor, but engine load as well. It's a better system for a street car.