Vacuum Advance - 1955

Started by D.Yaros, May 22, 2010, 09:43:33 AM

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D.Yaros

Is my thinking correct that to disconnect the distributor vacuum advance in order to connect a vacuum gauge,the only way to do it is to remove the fitting in the base of the carburetor, at the throttle body?
Dave Yaros
CLC #25195
55 Coupe de Ville
92 Allante
62 Olds  

You will find me on the web @:
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Otto Skorzeny

You can disconnect the vacuum line from the advance at either end. Just make sure to plug it up. Where are you connecting the gauge? Are you disconnecting it to set the timing or just check manifold vacuum?
fward

Ask not what your country can do for you, but what you can do for YOURSELF

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D.Yaros

Otto,

I would be disconnecting it to set the timing, or to time the engine with a vacuum gauge.
Dave Yaros
CLC #25195
55 Coupe de Ville
92 Allante
62 Olds  

You will find me on the web @:
http://GDYNets.atwebpages.com  -Dave's Den
http://graylady.atwebpages.com -'55 CDV site
http://www.freewebs.com/jeandaveyaros  -Saved 62 (Oldsmobile) Web Site
The home of Car Collector Chronicles.  A  monthly GDYNets newsletter focusing on classic car collecting.
http://www.scribd.com/D_Yaros/

Otto Skorzeny

When setting the timing, You can disconnect the vacuum line to the advance at either end. Just be sure to put a rubber plug in the line or the fitting at the carb to keep it from sucking air while you're making your adjustments to the distributor.
fward

Ask not what your country can do for you, but what you can do for YOURSELF

HUGE VENDOR LIST CLICK HERE

John Washburn CLC 1067

Folks,

If one is going to hook up a vacuum gauge, it is not done at the carburetor fitting - wrong vacuum.

One needs to get the vacuum reading at the manifold, not the carburetor (we can discuss this if anyone is interrested).

Use the fitting for the windshield wiper motor.

Tha's my story.

John W
John Washburn
CLC #1067
1937 LaSalle Coupe
1938 6519F Series Imperial Sedan
1949 62 Series 4 Door
1949 60 Special Fleetwood
1953 Coupe DeVille
1956 Coupe DeVille
1992 Eldorado Touring Coupe America Cup Series

Glen

It depends on what you are trying to do.  I’ve teed off the vacuum advance line to check the vacuum advance curve verses vacuum. 

I don’t do it that way anymore.  I use a hand vacuum pump now.  No worries about the mechanical advance affecting the readings. 

Glen
Glen Houlton CLC #727 
CLCMRC benefactor #104

D.Yaros

Quote from: Glen on May 24, 2010, 12:56:27 AM
I use a hand vacuum pump now.  No worries about the mechanical advance affecting the readings. 

Glen
Glen, care to explain the procedure?  I ask, as I do have a vacuum pump.  Where would one connect it?
Dave Yaros
CLC #25195
55 Coupe de Ville
92 Allante
62 Olds  

You will find me on the web @:
http://GDYNets.atwebpages.com  -Dave's Den
http://graylady.atwebpages.com -'55 CDV site
http://www.freewebs.com/jeandaveyaros  -Saved 62 (Oldsmobile) Web Site
The home of Car Collector Chronicles.  A  monthly GDYNets newsletter focusing on classic car collecting.
http://www.scribd.com/D_Yaros/

Glen

I connect the hand vacuum pump to the vacuum advance unit in the distributor and plug the line going to the carb or manifold.  With the engine running at idle to prevent the mechanical advance interfering with the test, and using a digital timing light, I slowly pump up the vacuum pump.  Comparing the vacuum gage on the pump and the timing mark on the harmonic balancer I can check the vacuum advance curve. 

Using this technique I discovered that the vacuum advance units I buy from the parts stores are going well beyond the 12 degrees advance for my 68 ELDO.  I installed a plate to block the VA from going beyond 12 degrees and I no longer have pinging at a steady pull up a slight hill. 

Glen
Glen Houlton CLC #727 
CLCMRC benefactor #104