Why does my 74 have a vacuum advanced distributor

[buckweber]

I have read multiple times that the Tii does not have vacuum advance. Mine does. Is it a problem?

 

 

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[esty]

if it runs ok, no problem

[Simeon]

'74 was a one off attempt to comply with US emissions with the tii. 

[OriginalOwner]

my '74tii has vacuum advance as original equipment.

 

Cheers,

 

Carl

 

Edited September 14, 2017 by OriginalOwner

['76mintgrün'02]

hmm, vacuum advance on a 74 tii ?

 

aren't they vacuum retard distributors ?

 

the pod pulls the points plate clockwise, correct ?

 

[OriginalOwner]

hmmm, good question.  I always assumed "advance."  It got my curiosity up and I found this, which may be helpful ......

   

 

Cheers,

 

Carl

 

Edited September 15, 2017 by OriginalOwner

['76mintgrün'02]

which way does the pod pull on yours?

perhaps you could post a photo, or the part number.

photos are preferred though.

way more fun than numbers.

[OriginalOwner]

I'll be reunited with my '74tii on Monday (needed a truck for a couple of days), so I'll take a closer look and see what's what ......

 

Cheers,

 

Carl

 

[Conserv]

On 9/14/2017 at 9:11 PM, '76mintgrun'02 said:

hmm, vacuum advance on a 74 tii ?

 

aren't they vacuum retard distributors ?

 

the pod pulls the points plate clockwise, correct ?

 

 

+1

 

The '74 tii's have vacuum retard distributors.  

 

Below is the pertinent section from the 1974 U.S. model brochure (no one would make up vacuum retard if they weren't forced to by emissions requirements!).  The distributors, indeed, have centrifugal advance, but vacuum retard -- and I believe that's from 1974 through 1976 for the carbureted U.S. models.

 

Regards,

 

Steve

 

Edited September 16, 2017 by Conserv

[worzella]

Yikes. I think the guy who wrote that manual worked for the IRS ?

[JohnS]

Yup.  The 74tii distributors are retarded

[John76]

Is the retard circuit connected to manifold vacuum on both models?

[OriginalOwner]

The vacuum hose from the distributor is connected to both airbox and plenum.

   I found some pictures I had taken a few years ago !!

 

And I can now understand the concept of "retard" ..... since the shaft spins clockwise, the vacuum thingie will pull the points base plate in a clockwise direction, thus in a direction to "retard."

 

Cheers,

 

Carl

Edited September 15, 2017 by OriginalOwner

[buckweber]

It appear that the plenum pulls the points counter clockwise

 

another question.  I believe I time to the ball on the fly wheel.  I also marked the crank pully.   What degree of advance is the ball and at what RPM do it time to.   I see a lot of info on max advance but haven't gotten that far.  

 

Thanks again

['76mintgrün'02]

18 minutes ago, buckweber said:

It appear that the plenum pulls the points counter clockwise

that would suggest that it is not the original distributor.

what is the model number?

 

 

The BB is at 25 degrees before top dead center.

 

Using the stock timing prescription, with the BB at xxxx rpm may not apply, with a non-stock distributor.

 

Do you have a timing light with the variable advance feature?