Columbia Vacuum Plate

[Russ/40]

I'm looking for this item, but need advice as to how large the Vacuum holes need to be to meet the shifting requirements of the vacuum cylinder. Any help appreciated.

 

[glennpm]

Hi Russ,


The vacuum plate connection is 1/4"NPT. You need part number B-49K which has the plate, longer studs and two gaskets.


Glenn

 

[KGS]

I'm looking for this item, but need advice as to how large the Vacuum holes need to be to meet the shifting requirements of the vacuum cylinder. Any help appreciated.

Russ, To get proper vacuum, make sure the plate you get pulls vacuum from
both venturies. There are some plates that only pull from one side. I think
they are for gas fed heaters.

Ken

 

[glennpm]

Hi,


The Columbia is to be shifted with your foot off the gas, i.e., both throttle plates are closed. The vacuum source must be manifold vacuum and not vacuum above the throttle plates.



"The driver then takes his foot off the accelerator pedal (to create maximum vacuum) and fully depresses the clutch which completes the shift."


Glenn

 

[Bored&Stroked]

If you have a low-vacuum situation, you can also put in a vacuum tank - with a one-way "flapper valve" - such that you store vacuum. This is the same principle that is used on many brake boosters.

 

[4dFord/SC]

FWIW, when I first installed my Columbia, I drew the vacuum from a T in the wiper supply hose. It was a little slow in shifting, but otherwise it worked fine. (I later installed a supply port in the phenolic spacer under my 4bbl carb, and now it shifts instantly.)

 

[doghair3]

Where do you fine the vacuum plate with part number B-49K?

 

[4dFord/SC]

Where do you fine the vacuum plate with part number B-49K?

Columbia Two Speed Parts: http://www.columbiatwospeedparts.com/