Zenith Manifold

[husky drvr]

at least the Max torque was not improved over the Sports Version.

Bernd_st,

Considering the almost 10% drop in HP. @ a 200 RPM. lower peak, to achieve only a one Ft.lb. drop in torque peak at the same RPM. would have needed some careful efforts in tuning.

I should have included the figures for the Solex carbed versions as well. The HP. and torque drops were smaller.

The ST lost ground, but the GT gained HP. but lost one more Ft.lb. Considering how much difference in venturi area between Solex and Zeniths, think I would have expected a larger difference, at top end.



This gives a new question for pondering considering the short production run of s3's and the mid-run changeover to the Solex carb set-up. Is it possible the Zenith carbs were used as a Production "band-aid" because the Solex system
just wasn't ready in time for Rootes planned production change over?

Have a good evening,

 

[bernd_st]

A very interesting comparison bringing up new thoughts. Appearantly Rootes indeed tried to bridge the time until the Solex carb intro with the "tamed" Zeniths. This would explain the sudden intro of "Power Valve Version" too. Would suspect there must have been a considerable cost saving with the less complicated Solex setup too. Anyhow despite the better performance numbers of the Solex it was a bad decision in the long term. Many Solex's suffer from non opening 2nd stage. The vaccum operated 2nd stage control turned out to be a complete fail...

 

[alpine_64]

This gives a new question for pondering considering the short production run of s3's and the mid-run changeover to the Solex carb set-up. Is it possible the Zenith carbs were used as a Production "band-aid" because the Solex system
just wasn't ready in time for Rootes planned production change over?

Im not sure the Zeniths were a band-aid solution . The series 3 for me was the defining example of the mess Rootes was.

They introduced a new model that was a bridge between the early cars SII and the later small fin cars ..

The series 3 introduced:
the ST/GT models.
The new telescopic rear suspension
The new steering
New interior
New windscreen
New soft and hardtops
New fuel tank setup.
New steering column and wheel.
New pedal setup

However in this they made a model that lasted less than a year... And in that time..

Had 2 different seat types ( early split lower squab)

Had the new fuel tanks and relocated the filler to the top of the guard.. requiring a unique finishing ring and new petrol cap that were both deleted on series IV

the fuel tank on a S3 has a unique tank and filler pipe.

Had a unique axle / OD setup ( that should have been retained)

Used 2 styles of series 3 shield inserts.

4 different carburettor setups and 2 manifolds.

4 different air filter setups.

And there were some other unique things that slip my mind right now....

But a heck of a lot of unique parts to a model that was less than 1 year and they superceded them in that time.... Crazy.

 

[bernd_st]

Because of the many design try outs and for me the S3 is one of the most interesting models though, even I don't own one - yet. You can study for monthes if not years, but you still find exclusive S3 solutions. Rootes must have been in a design turmoil in that very timeframe almost desperately trying to adapt the rather successful S2 model to more modern end user demands. A good example is also: Why did they try out new metallic colours which were not continued later ? Anyway still fascinating to further dig into S3 specifica...

P.S. A fellow club mate has recently restored one the 6 original works S3 GT prototypes with automatic B/W gearbox. In our club circle we didn't even know before that something like that existed. The whole deep dive/ investigation started when another club member advertised an obsolete empty S3 body hanging on his workshop wall with a very early SIV VIN#. In the beginning we thought there must been a VIN switch, but then we found that telltailing widened gearbox channel and a square shifter cutout. The riddle resolution got started and the restoration became a rather lengthy & cumbersome job. It's registered now, on the road and an absolute beauty in Autumn Gold metallic. Have a look:

 

[twautomotive]

It never ceases to amaze me how much information is known and more importantly, shared in the club. Kudos to everyone who answered this thread!!!

 

[alpine_64]

P.S. A fellow club mate has recently restored one the 6 original works S3 GT prototypes with automatic B/W gearbox. We didn't even know before that something like that existed. The whole deep dive/ investigation started when another club member advertised an obsolete empty S3 body hanging on his workshop wall with a very early SIV VIN#. In the beginning we thought there must been a VIN switch,

View attachment 34179

@bernd_st I think the more correct description is its a prototype series IVGT .. so based on a series 3 car....

That also makes me wonder.. how many series 3 prototypes were built on series II platform.. what was the lead time for the S3.....

 

[alpine_64]

Im not sure the Zeniths were a band-aid solution . The series 3 for me was the defining example of the mess Rootes was.

They introduced a new model that was a bridge between the early cars SII and the later small fin cars ..

The series 3 introduced:
the ST/GT models.
The new telescopic rear suspension
The new steering
New interior
New windscreen
New soft and hardtops
New fuel tank setup.
New steering column and wheel.
New pedal setup

However in this they made a model that lasted less than a year... And in that time..

Had 2 different seat types ( early split lower squab)

Had the new fuel tanks and relocated the filler to the top of the guard.. requiring a unique finishing ring and new petrol cap that were both deleted on series IV

the fuel tank on a S3 has a unique tank and filler pipe.

Had a unique axle / OD setup ( that should have been retained)

Used 2 styles of series 3 shield inserts.

4 different carburettor setups and 2 manifolds.

4 different air filter setups.

And there were some other unique things that slip my mind right now....

But a heck of a lot of unique parts to a model that was less than 1 year and they superceded them in that time.... Crazy.

I just recalled the other unique S3 part.. the light switch.. for an overdeive car... it has 3 resistors atop so that if the car has the light on...and overdrive js engaged...it dims the overdrive warning light .. great attention to detail... And actually a good idea as the opal light is bright ...but they stopped using it after S3...and was a unique part for S3 Od cars...

Also the other unique S3 part ..the ST dash...the raised gauge area like the early cars . But the unique texture finish and the holes for the s3 introduced the warning lights.. the round faceted ones.. which I think may have also carries over to early SIV.

Then there was the introduction of the self cancelling OD switch and the special relay...the new column shroud and new indicator and OD stalks.... The steering wheel and horn setup...

Introduction of the vinyl tool roll.... The list goes on ...

 

[bernd_st]

@bernd_st I think the more correct description is its a prototype series IVGT .. so based on a series 3 car....

That also makes me wonder.. how many series 3 prototypes were built on series II platform.. what was the lead time for the S3.....

Indeed, ultimately it's a Series IV prototype since Auto gearbox was never offered on the S3. Nevertheless the body except the transmission tunnel & the features are still all S3. Wonder if you spotted the Webasto folding roof on the Hardtop which the owner added as an extra. Even though not being original, but giving a nice feel during driving on hot summer days ...

Sorry, no clue regarding whether there were S3 prototypes. At least never heard about any...

 

[alpine_64]

. Wonder if you spotted the Webasto folding roof on the Hardtop which the owner added as an extra. Even though not being original, but giving a nice feel during driving on hot summer days

I did spot it, but not a fan of that mod.. also seen them on a HLM....even worse.... I think they remove the point of a hardtop.. and the extra fairing on the front ruins the lines.

Rootes did experiment with a fiat 500 / 2CB style full folding back roof that kept the side rails but it didn't go anywhere.

With some engineering tou could do a surrey style hardtop.. that could be an interesting experiment with a Honeyborne FG top...but I think you'd have to work out a very strong clamping system for the rear portion when in open configuration

 

[Mike O'D]

Speaking of dashes, at least some of the S3 STs had flocked (fuzzy) dashes. Mine was faded and a lot of the fuzz worn off, but under the edged of the instruments it was still in good shape. The original flock was finer in texture to what I was able to find, but looks really great. A friend said it looks like the inside of a jewelry box with the instruments being the jewels.

 

[SoCal'beaming]

Hi All ... Looking for this particular intake mani. with the port for the brake servo. ... Any help or leeds much appreciated!

.... Thanks, David

WOW! ... What a wealth of knowledge becomes available 'cause you ask a simple question. What a grand membership this is!

......... Thanks Everyone, .. David

 

[jdoclogan]

My Series III GT was purchased from the original owner in 1992 that lived a few miles from me. It sits on one of my car racks and I haven't looked closely at it in years. Maybe its time to get the ladder out and have a look. VIN B9205283.


It has a laminated Burl Walnut dash. I recall prepping and painting it in the original code 39 Carnival Red with PPG Durethane aircraft paint. Other than that it has an excellent original interior and numbers matching 1592 engine.

 

[Mike O'D]

Bring it down and take it for a drive!