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Original Zenith to manifold gasket...

bernd_st

Bronze Level Sponsor
Interesting NOS find but diameter and hole distance doesn't quite fit the Zenith's. Would assume they are for a SV or later since they match the Stromberg/Manifold pattern :

IMG_20200209_133626.jpg
 

65beam

Donation Time
Interesting NOS find but diameter and hole distance doesn't quite fit the Zenith's. Would assume they are for a SV or later since they match the Stromberg/Manifold pattern :

View attachment 18764
This spacer was used on all models of the Hunter range using either single or dual Stromberg carbs except for a Hunter GT and cars built for the USA market. It's not for a series 5 Alpine.
 
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bernd_st

Bronze Level Sponsor
Michael : That manifold came from a S3 but will use it on my HLM...

65beam : Thought so. Thanks for clarifying. See no reason why they shouldn't fit a SV. Perhaps a worthwhile addition since they suffer even more badly from excessive heat...
 

65beam

Donation Time
Michael : That manifold came from a S3 but will use it on my HLM...

65beam : Thought so. Thanks for clarifying. See no reason why they shouldn't fit a SV. Perhaps a worthwhile addition since they suffer even more badly from excessive heat...
I have series 5 carb set ups that have a similar gasket but it's considerably thinner than the above gasket you're showing.
 

bernd_st

Bronze Level Sponsor
Might well be. Most SV however used simple paper gaskets...

This actually reminded me that I bought a SV hot running kit from John H. In UK earlier. Never tried nor opened it but interestingly it's an excellent fit for the Zenith's as well. It even came with height reduced nuts. Looks great isn't it ?

IMG_20200209_163827.jpg
 

Limey

Donation Time
Hi Bernd,

I have these. 7mm thick. Same material as the base to main part gasket. I tried to fit them this weekend but the only trouble was is that the 7mm lift caused the petrol feed to foul the expansion tank - see pic So I took them off. Having the fuel pipe so hot would negate any advantage given by the gaskets.

Regards,

Oliver
IMG_2511.JPG
 

bernd_st

Bronze Level Sponsor
Oliver, good that you tried it in situ. Valid point - didn't think of it yet...

Any attempt to achieve cooler running in your case would already be inhibited by hot water flowing through the manifold. Better to disconnect that first. I know it's not original ,but the difference is almost breathtaking. Rootes recommended it with their tuning kits ( for race application) so I think this modification is tolerable and brings a substantial power increase. The next step then would be to play with the gasket thickness...
 

Limey

Donation Time
If it was an in-period Rootes sanctioned mod then that's original as far as I'm concerned. I can't imagine why they did it. I mean, who wants warm inducted air? No one.

A job for the weekend. what series Alpine does the single brass pipe come from to replace the Y piece at the front?
 

bernd_st

Bronze Level Sponsor
They did it because our cars were run all year , incl. Winter times where warm up took longer without hot flow through the manifold. Since we nowadays run our cars only in warm weather that approach is contraproductive. Specifically on engines likes the Rootes one where Inlet/ Outlet ports are located on the same side meaning a certain degree of heat up is already imminent.

The single port brass outlet you can take from any series head. It's the same as the heater core tube outlet...
 
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Limey

Donation Time
I would have thought that the heat of the exhaust would get the temp of the inlet manifold up faster than waiting for the T/stat to open...I can understand it on a saloon but surely not a smart thing to put on a soft top sports car. Ah well.

The one on the cylinder head, carb side? Thanks. I'm in the office so was running through the engine in my head and forgot that one.
 

Limey

Donation Time
Well Bernd, thanks to you I have upgraded my carbs from Hillman husky van spec to SII spec. It was the elephant in the room. Nice shiny NOS carbs for show but wrong specs and slack performance. The last piece of the jigsaw. Thanks Bernd!

Choke from 25 to 30
Main discharge jet same /same (016289)
Main jet 115 to 145 (new ones thanks to Ebay France)
Bypass jet blank/blank
High speed bleed 60 to 100 (drilled out in situ. Easy)
Slow running 45 to 50
Progression holes 8/8 to 10/10 (used a good SII base)
Accelerator pump jet 50 to 70
Fuel pressure reduced by shimming the petrol pump and adjusting the floats so no more fuel leakage and manifold 'varnish' A cheap manometer is essential for this. How many Alpine pics have that brown staining on the manifolds and carbs?

Spent some time getting the throttle at .7mm at full choke on both. Balanced with 'Vacucarb" tool. Now it sounds better, revs better. No flat spots.

I backed the timing to 5-6 degrees and used 4 yes 4 Gunson colour tunes simultaneously (!!) to get the mixtures right. Once she's broken in I'll put her on an easy rolling road for a final tune of the advance/retard/mixture.

Next is to blank the manifold hot water foolishness as per tuning manual upgrade

I stuck some very fruity race fuel in my 5ltr TVR Griffith in the summer and it makes a HUGE difference. So I think maybe 25ltrs of 102RON Ethanol free 3.7%oxygen by weight for the rolling road tune up will be amusing and if it yields results then why go back to the pump;) there is the cost of £4 per litre and short shelf life but then think of the £1o000s spent on a resto. Race fuel costs fade into insignificance but work like cocaine (or if you prefer it legal, Viagra)
 
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bernd_st

Bronze Level Sponsor
Wow, sounds like you made it. Hot water disconnect will bring you to another level. Your HA will fly...
Bring it to the Spares Day please ! Want to join you for a ride ;-)

P.S. Didn't know that you have a Griffith....
 
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Limey

Donation Time
Wow, sounds like you made it. Hot water disconnect will bring you to another level. Your HA will fly...
Bring it to the Spares Day please ! Want to join you for a ride ;-)
Thanks Bernd! A month ago my understanding of Zeniths was zero but thanks to you I had a closer look and now perhaps I have a better idea of how they work. Now that I've read up the Zenith operating and tuning guides that were gathering dust I appreciate how good they are. And they must have been very good to win the Index of thermal efficiency at Le Mans, a crown that Porsche and other well known marques wanted very much that year. I've read it was the 2nd most prestigious prize after an outright win in those days. So hats off to Zenith carbs!
 

bernd_st

Bronze Level Sponsor
Many people don't believe in their potential and put Weber's instead. Easy, but not the same. The Zeniths - properly set up - were much better than most people would believe. There are some more potential improvements which we can discuss on the Spares Day...
 
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Limey

Donation Time
Many people don't believe in their potential and put Weber's instead. Easy, but not the same. The Zeniths - properly set-up were much better than most people would believe. There are some more potential improvements which we can discuss on the Spares Day...

I look forward to spares day very much. I always get there too late to chat with you and the other 'movers and shakers' Maybe we should meet for a good meal and beers the night before to talk Alpines and Harringtons?

I heard that Hartwell offered a special Alpine Inlet manifold ( not as part of the Harrington tune tho') but in 10 years searching the darkest recesses of the Hartwell/Imp/autojumble world I have never even seen a pic or advert so I doubt its practical existence. Brabham offered one but it was just a standard Alpine one with crude and ineffective cooling fins.

I'm a factory original sort of chap but an easy to make heat dissipating plate between the exhaust and inlet manifold must surely add some BHP for a daily driver?

I have recently bought at some expense a 1960s pair of Italian sand cast Weber carbs. These are not especially rare but most are beyond returning to NOS due to corrosion but this pair are very good. I now doubt my 'investment'. I imagine Webers will perform better at full revs (racing conditions) with demanding cams and flows, but the Zeniths will give better all round performance as intended. I wonder if Webers still ride on the 60s/70s home custom kudos of stock carbs are good but Webers must always be better. In my day and even now Webers are THE carbs to have for classics. I hear they can be hard to set up unless by a Weber specialist with lots of costly rolling road work and then need constant balancing? Perhaps this is also a myth. I am open minded.
 

Gordon Holsinger

Diamond Level Sponsor
I look forward to spares day very much. I always get there too late to chat with you and the other 'movers and shakers' Maybe we should meet for a good meal and beers the night before to talk Alpines and Harringtons?

I heard that Hartwell offered a special Alpine Inlet manifold ( not as part of the Harrington tune tho') but in 10 years searching the darkest recesses of the Hartwell/Imp/autojumble world I have never even seen a pic or advert so I doubt its practical existence. Brabham offered one but it was just a standard Alpine one with crude and ineffective cooling fins.

I'm a factory original sort of chap but an easy to make heat dissipating plate between the exhaust and inlet manifold must surely add some BHP for a daily driver?

I have recently bought at some expense a 1960s pair of Italian sand cast Weber carbs. These are not especially rare but most are beyond returning to NOS due to corrosion but this pair are very good. I now doubt my 'investment'. I imagine Webers will perform better at full revs (racing conditions) with demanding cams and flows, but the Zeniths will give better all round performance as intended. I wonder if Webers still ride on the 60s/70s home custom kudos of stock carbs are good but Webers must always be better. In my day and even now Webers are THE carbs to have for classics. I hear they can be hard to set up unless by a Weber specialist with lots of costly rolling road work and then need constant balancing? Perhaps this is also a myth. I am open minded.
I am in the process of moving I have in my archive a Hartwell catalogue for Alpines 1971-2 vintage. I owned a S II at the time when I dig it out I will post it
 

alpine_64

Donation Time
@Oliver.

Re the race fuel, yes it degrades quicker (or more accurately the combustible separates faster) while im not a fan of snake oil.... The Stabil addative helps a lot on that front and does a great job of keeping the fuel together. Also making sure the tanks are full when the car is parked long term helps, the less air in the tank the slower the separation.

Re hartwell manifold, i believe that the very short straight in they used on the Harrington alpine road test car that was stage 3 + 2x40dcoe (maybe dco?) Webers. You can really see the manifold in the photos.

The Brabham dcoe manifold was a straight inlet but appeared to stagger the carbs height front rear and had cooling ribs on it.

Re: the use of Zenith at Lemans in '62 when they won the ITE class the cars could have modified bodies but not mechancial components, they had to be stock homologated parts.

In '63 when they went for maximum performance at LM and the tour de France they ran 2x40mm webers. They homolgated the webers for FIA comp but not production class.

The Zeniths when setup well produce decent power but not on the level of webers when they are set well. Webers are a progressive carb setup so they are very adjustable but that means more room for error. There are some decent starting jet settings for alpines and there are supoosed to be a few knowledgeable alpine/weber tunning guys in the UK so if you went that path im sure it would work out.

What are your thoughts on the period aftermarket conversions like Alexander, Nerus etc?
 

Limey

Donation Time
Wow, sounds like you made it. Hot water disconnect will bring you to another level. Your HA will fly...
Bring it to the Spares Day please ! Want to join you for a ride ;-)

Where can I find the 2 blanking plugs for the manifold and the one for the engine block? Any ideas or photos?

P.S. Didn't know that you have a Griffith....
Yes, For 15 years. It is just completing an 18month rebuild at Central TVR in Derby. The best bit is the 5.2ltr upgrade to the Rover V8. 350bhp + 360lbft torque in a 1000kg car:) Everything else is factory standard (as you would expect!) No roll bar, no ABS, No traction control, no power steering or aircon. NO silencers:D No crumple zones. We die together.
 
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