I stand corrected Chris - put pen to paper before I'd finished calculation! Its down to the old grey matter.
124 bhp @ fly wheel Ed.

Hello Makem

I agree that some club members will want to change things about a bit to make their Alpines more fun for them to drive but the point I was trying to get over was that it seems not many in the club are trying to keep their car as a pure Alpine. I totally agree that there will never be many genuine concours cars, the comment you make about most changes being made before a car reaches classic status is exactly right. My point is that if the clubs objective is to preserve the marque then more people should be encouraged to return the cars to original factory spec, when undergoing restorations, or we will only have pictures left to remind us of this great little car.

I have only been an Alpine owner just over a year but have never seen a factory spec car. I don't mean down to original light bulbs ! But just a car say with matching numbers that has it's original wheels and paint-work etc.

Yes... it does take a long time to restore a car whatever spec you are restoring it to. We are very lucky in the club at the moment to have the likes of Chris and Eddie with their extensive knowledge to refer to when we have a query but we must encourage new owners like Oliver with his Series II project and me with my Series IV, who want to keep a car on the road that is period correct or there will be no genuine point of reference in the future. Perhaps we can have a section in the Horn, devoted to originality questions?

We all respect each others decision to keep our cars in a state that suits us, beauty is in the eye of the beholder after all, but I bought a classic car from the 60's because I wanted to enjoy that nostalgic feeling that a car from that period brings, if i wanted a fun car that i could take the top off that had better brakes, good handling and was fairly quick, I would have bought an MX5!

Just to keep this post in the correct department, I have attached a picture below of my carburettor, which I am in the process of recalibrating to the original standard settings... as to make sure the leaded fuel it uses, gives every bit of HP I can get...so i can try and keep up with you modified boys!!

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That is a beautifully restored engine bay Alvin ( or should I say John ) everything there looks pretty much as Rootes made it. Even down to the wire mesh air filter on the Solex. I stongly advise you NOT to buy David Vizard's book because when you read what he says about the effect this will have on your lovingly restored rebuilt engine you will want to hurl it into your landfill wheelie bin.

My Solex came straight off the car and went straight into the dustbin, and I've never regretted it for a moment.
Rootes made plenty of mistakes whilst producing cars, the number of service bulletins that Chris has unearthed over the years bears testament to this. They were not infallible.

Keeping your car original is to me like having to hear a bum note during your favorite piece of music every time it's played. Rootes endeavoured to improve their product during it's service life with the benefit of hindsight and field testing. What we are doing is just following that process through albeit some 50 years later.

I applaud the work you have done and wish you all the fun it will undoubtedly bring chatting to likeminded owners. The club will always embrace your ideal in keeping your car original. Long may it continue.
But equally there are those of us, getting long in the tooth, that remember the faux pars only too well. That's enough off topic now.

Regards Eddie

Actually that bit on filters leads me onto this post. During more tests done at A.P.T on filtration systems there was a number of different types of filter tested for efficiency of filtration and absolute flow rate.

The old familiar wire mesh filters as seen on the Solex were also tested.

The worst filters in terms of efficiency ie removing abrasive particles were the oil bath and wire mesh types. Ok yes they stop rocks getting in but the micro abrasive particles of fine metallic dust from brake calipers get right into your engine where they exact a terrible toll on pistons and rings.

The only good thing is they flow well but at a terrible price to pay.

The best filtration system was that made by K&N. These are made of cotton fabric that is reinforced with wire and treated with a special oil and are recleanable. The flow rates obtained through these was such that in effect the amount of air entering the induction system was indistinguishable from no filter at all whilst removing absolutely every particle present in the air.

They were found to operate at this level for mileages in excess of 100,000 miles before cleaning or replacement was necessary. No paper system came anywhere close to this performance. Fit a pair of these to your Series 5 and become a very happy bunny because performance will be markedly improved.

The standard paper filters strangle the intake to a large extent hampering potential performance to a large degree.
Finding the right parts means a visit to Southern carburettors who are a K & N stockist but once we know the correct filter I'll post on this thread.

Regards Eddie

And so with filtration we come to the big downside of the Weber 28/36 DCD. Height. The thing is so tall it is impossible to get anything taller than a couple of inches on top of the carb. without the bonnet fouling it.

Which is why Rootes fitted that appalling filter to the Solex which was equally tall. When I bought my carb it came with a 1 inch thick pancake air filter with a foam element. This rotted and crumbled away within a few years and by then the only pancake filters available were invariably too tall. Banging against the bonnet on hard acceleration.

I thus decided to build a cold air intake and plenum incorporating a .............you guessed it , a wire mesh packed cartridge. This was supposed to be an experimental temporary set up to evaluate whether the idea worked. As documented in the Horn it was highly successful, and is still on there all these years later, but it looks very garden shed, if you know what I mean.

In my quest to find something commercially available I believe I have found the natural successor to the legendary 28/36 DCD. It is another twin choke Weber and the model is the Weber 32/36 DGV 5A.
Part Number22680.005

Not only is this carb widely available but the jetting is for a Ford Mexico engine 1600cc and the jet sizes are as follows

Chokes .......................26/27 mm ( fixed )
Main Jets......................140/135
Air Jets.........................165/160
Idle Jets........................55/50
Emulsion Tubes..............f50/f6
Pump Jet........................50
Needle Valve...................200

I have ordered one and intend to fit it before the National.
If you want to see the set up come to the National and find out more.
The big advantage this should have over the 28/36 is still more flow, because of that 4 mm increase in the primary barrel but also it is a lot more compact which means more height to fit a commercial plenum which are available for this carb. In fact I intend to fit a K&N Apollo Cold air intake to take full advantage of this breakthrough.

See the following links.

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You'll notice there are two versions of this carb,
One is just like 28/36 DCD and features a progressive combination of both chokes. ( The version I ordered ).
The other is a syncronised butterfly, both chokes open together.
This is the one favoured by hot rodders and Formula Ford racers who don't particularly care about economy.

Following in the 28/36's footsteps this looks like being the next legend.
Of course I might be wrong but it looks highly promising.
Best Regards
Eddie

New Webers aside, if you are lucky enough to own a 28/36 DCD then these are the jet sizes recommended by Derringtons the tuning specialists mentioned by Chris in an earlier post. Chris also listed these sizes in another thread but I couldn't find it to link to.

So pardon the repetition.

Venturi................................26mm.........................27mm
Main Jet...............................140.............................160
Emulsion Tubes.....................F30.............................F30
Air Correction Jet..................220.............................180
Slow Running Jet....................50..............................70
Pump Jet...............................70

Now if you intend to run Twin DCOE's then you might find this recommendation from Derrington's ( taken from Chris McGovern's book Alpine the Classic Sunbeam ) useful

Auxiliary Venturi..........................3.5
Venturi ( Choke ).........................30mm
Main Jet.......................................120
Emulsion Tubes............................F16
Air Correction Jet..........................175
Slow Running Jet...........................45F9
Pump Jet.......................................45

Chris McGovern was also a fan of Twin 1.5 inch SU's which were commercially available from Alexander Engineering among others, and used them on his Black Alpine very successfully.

Next we'll look at how David Vizard recommends setting up the 28/36 DCD which will probably be equally relevant to the other progressive twin chokes as well.

Regards Eddie

Now we'll assume you have a correctly reading tacho. The tacho on the Alpine is notorious for reading excessively if it hasn't been overhauled in recent years as seen in the thread with this link

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So when I refer to certain R.P.M if your tacho is original you won't get low enough readings to make sense of it. Be Warned OK.

Also we'll assume your timing is correct both dynamically and static and your tappet clearances are good as well. These all interact so the carb set up should be left until all this is shipshape. Not forgetting spark plug gaps as well.
All carb work should be done on a thoroughly warm engine too after a decent run.

Now set the idle speed with the throttle stop screw to around 1000 rpm.
Now turn your attention to the Idle Mixture screw at the base. Unscrewing this will richen the mixture whilst screwing it in will lean it.

Right screw this in until the RPM start to drop. Now screw it out until RPM peaks, if it then slows go back to peak setting. Now screw it in half a turn.
If you have the correct idle jet in the primary barrel then this setting should be about halfway point of it's adjustment. If it's noticeably too far in or out , first clean out all jets and drillings with carb cleaner. Gum can block the idle transition circuit on these carbs after a few years dormant.
If still not in the middle, get the correct jets and service kit and overhaul the carb, paying attention to all drillings and linkages.

That's all there is to it, provided you have the right jets, you should be able to set your tickover to around 700/850 rpm, nice and smooth.
Regards Eddie

Hi Eddie,
In responce to you point on tacho's, please try to understand that I have been trying to get information regarding Alpines in all their respective series and found it can often be a minefield of shortage of information. Not to mention missinformation and I have often bought components from auction and good sources, only to find that although I have checked the item would be correct for the job in hand, have found it not to be so.
The two vehicles I have are made up of Rootes parts but also Ford and BMC parts and where the non Rootes parts are concerned Messers Bodgit and Scarper have had a rather large hand. This means that I have to ask a lot of seemingly daft questions to get to where I want to be. That includes assuming (this makes an enemy of exactitude) that the tacho fitted to my car was the correct item.
Paul

Paul...the only way to check that you are fitting the correct spec parts for your car is to use the Alpine parts list book. It gives all the parts and changes in spec through all the different Series.
What series do you have ? If It's a series 1V...I can help.

Hi
Thanks for the reply.
I have two Alpines, a SIV and a SV and have spent many hours searching through the net for a good understanding of what exactly should go where.
I'm not trying to get a pair of concourse condition cars, but I am trying to stick to rebuilding to a good representative example of the respective series.
Thanks
Paul

Interesting discussion. Would absolutely agree that dual 40 DCOE´s do nothing good on an otherwise standard engine. Strombergs are being discussed back and forth and feel while they lack ultimate performance at least they are very economical. Have not yet tried Weber 28/32DCD´s myself yet but a club mate is running this carb setup on a SIV auto and it´s going like stink.
Just to bring another "taste" into that discussion and perhaps a bit surprising for most of you I do get the best results from a tuned/tweaked dual Zenith setup. I´m not only rebuilding them as a hobby but running them with 30mm venturis /145 main jets and they really make my S1 fly. Anybody with similar experiences ?

Once again in Chris McGoverns book he discusses the Twin Zenith set up in detail. One important point made is that The Le Mans cars performed superbly with this set up and the cars achieved 115 mph on the Mulsanne straight and won the coveted Index of Thermal Efficiency to boot.
If that isn't the ultimate set up then someone please show me something better.

I have never seen this set up on a later Series car but I have a gut feeling that it would be a real eye opener on a Holbay engine.
If anyone does feel like trying this please let us know what happens.

Best Regards Eddie

Eddie
As (I presume) I am one of those you mentioned in your earlier post as one of the Surrey group owners with 28/36DCD look alikes, I should say that it is a Weber 36/36 (don't know if the DCD bit applies as well), or at least that's what the bloke in Southern Carburettors told me when I went to get some gaskets for it. This carb was on the car when I bought it, and as the previous owner had the car for over 20 years, it may well have been on the car for quite a while. The difference seems to be that on the 28/36, the second barrel comes in progressively, whereas on the 36/36, the butterflies are permanently linked by a sort of cog wheel arrangement and operate together equally - wear and tear excepted. Wouldn't this give an approximate duplication of the characteristics of the Series I/II/early 3 pair of Zenith WIP 36's?

I have no idea what jet sizes are in it, as I haven't got the nerve to take it apart, or indeed whether they suit the engine. The engine is no ball of fire, so perhaps not, but it also has this water heated manifold that you don't like (which I went to a deal of trouble to replace when the steel water pipe rusted through) and as it's a 3 GT, the less efficient 4 into 1 iron exhaust manifold, so these might make a difference.

Does your Vizard book have any guidance that might help please, as nobody else seems to have this carb set up?

Kind regards

Steve (3234)

When I had my Series IV I bought a brand new Solex (yes it was a while ago ) the car went off the road for a few years and when it came back the damn thing was useless so it went in the bin and was replaced with a brand new Weber 28/36 that never gave a moments trouble over the years, the Series 3 I restored after had the twin Zeniths See pic


I rebuilt them and messed about for ages, spent most of my time balancing them but in the end it was get a Series IV manifold and find a 2ndhand 28/36 had it rebuilt and jetted by Southern carburettors and the car better and smoother than ever before

Would regard your Zenith experience "kind of normal" . They are requiring some dedication and most importantly a proper rebuild especially in the throttle shafts area. After all no doubt the Weber 28/36 respectively 36/36 setup is seems to be the least problematic.

Perhaps I just like the challenge but the power the twin Zentihs return (in proper trim) is slightly outperforming any single Weber setup - we tried it...