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Zenith inlet manifold with interesting modification...

bernd_st

Bronze Level Sponsor
Just picked up an early series Zenith manifold from glass blasting and that PO appearantly had added two screw in vacuum pick off pipes. Haven't tried it yet, but could make sense when connected to a set of Motorcycle vacuum synchronizers...


IMG_20210620_105944.jpg
 

DanR

Diamond Level Sponsor
The design appears to me a bit offset.... The carb base(s) is/are not evenly situated between the inlet ports.

Odd at least to me.
 

bernd_st

Bronze Level Sponsor
May look odd, but that's how they came from the factory. Think there was no other choice in order to make enough clearance between the two Zenith carbs...
 

husky drvr

Platinum Level Sponsor
pics might help

Remember the fuel line goes straight into the carb body with a compression ferrule and fitting and then bends 90* behind the fitting. No banjo fittings allowed.:rolleyes::confused:



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bernd_st

Bronze Level Sponsor
Did Minxes come with dual Zeniths originally? Always thought they were exclusive to Rapiers as being the "Sports Coupe" in the range. Of course for Alpines too...
 

Kristian Jonsson

Donation Time
Did Minxes come with dual Zeniths originally? Always thought they were exclusive to Rapiers as being the "Sports Coupe" in the range. Of course for Alpines too...
No, only in my Minx (-66 1725 iron head.) I was lucky to get a twin carb inlet for the iron head, and I have some Zenit VIA: Tried to sell the setup, but no one was interested. Now my Minx run fine.
 

bernd_st

Bronze Level Sponsor
Alright. Awesome a tuned / flying iron head Minx in Sweden then :rolleyes:. Heard from a Rootes buddy in the Netherlands that the Iron head engines are extremely reliable. Never tried one yet but perhaps one day...
 

Limey

Donation Time
Hi Bernd,

For tuning my Zeniths and Webers I was planning to purchase 4 line manometer. The idea is to place the take offs x 4 in approx these positions on the Z manifiold and similar on the Weber unit. Just out of curiosity and for the hell of it.
 

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puff4

Platinum Level Sponsor
Hi Bernd,

For tuning my Zeniths and Webers I was planning to purchase 4 line manometer. The idea is to place the take offs x 4 in approx these positions on the Z manifiold and similar on the Weber unit. Just out of curiosity and for the hell of it.

I hate to say it, but that's not gonna work. The overall vacuum will remain pretty consistent and you won't see much, if any, difference between the intake runners. But have at it and tell us your results.
 

Limey

Donation Time
Indeed yes, for the Zenith inlet, you are, on reflection right, it being a sort of plenum (hence Bernds only have one per carb) and even then a carb top manometer would do the job just fine then..

However it would be suitable and correct for testing /balancing Weber set ups

Cheers,
Oliver
 
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puff4

Platinum Level Sponsor
Indeed yes, for the Zenith inlet, you are on reflection right, it being a sort of plenum (hence Bernds only have one per carb) and even then a carb top manometer would do the job just fine then..
However it would be suitable and correct for Weber manifolds tho.

Cheers,
Oliver
Correct. However, you could see the same difference simply by using a manometer (like a UniSyn) at the open throat of the Webers.

Oh, and Bernd's wouldn't work either. Both vacuum ports would read basically the same.
 
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Limey

Donation Time
Killjoy;) I want to see the readings for all 4 inlets simultaneously and buy some kit that I'll only use 2 or 3 times. Or is that just me?
 

beamdream

Gold Level Sponsor
Given that you only have 2 carbs to set I can't see much point in having a 4 point manometer, in any case the pressure pulses within the manifold would make any reading worthless.
 

bernd_st

Bronze Level Sponsor
Didn't spot that in the first place and coming back to the Swedish Minx :

You are missing the interconnecting choke connection steel rod. Furthermore your rear carb choke flap is kept shut. During normal driving condition both have to be fully and synchronously open, otherwise you won't get proper performance...
 

Kristian Jonsson

Donation Time
Didn't spot that in the first place and coming back to the Swedish Minx :

You are missing the interconnecting choke connection steel rod. Furthermore your rear carb choke flap is kept shut. During normal driving condition both have to be fully and synchronously open, otherwise you won't get proper performance...

No, it is removed. I don't need it. Both choke flaps are permanently kept open with a wire. At this very moment removed. Fabricating an air cleaner.
 
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