Hello
I have had rebuilt my engine with this set from Nanni I have purchased a 123 ignition and mounted on the engine but is in doubt about the settings for the curve, there are 16 different curves,
Is there someone who can help me with this.
http://www.fiat500sport.com/engine-...rading-500-r-126engine-700-cc-40-hp-0253.html
Regards Flemming from Denmark

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Hello Flemming and welcome to the forum.

When I fitted this unit to our car, because it was a standard 126 engine the unit worked fine in the default '0' setting.

However as your engine is modified it may well be different.

I am sure someone on here will be able to help further.

Flemming,

First, welcome to the list.

Second, congratulations on building what looks like a great little motor.

I also have an upgraded '695' in my 500F and it is similarly equipped with a 123ignition. Through a bit of experimentation I settled on Curve 1, that is, I used the standard factory advances of 16.8deg @ 2000rpm and 28.0deg @ 3000rpm with the built in 'idle control', though I'm not quite sure what the latter does.

I don't know what your ultimate specs will be, but the best way to maximise your power & tune is to use a dynamometer (rolling road). This is what I did and my engine runs very well.

Also, please bear in mind that your carby settings will have a major effect on performance.

Unfortunately there is no easy formula for the final setup as your planned driving style will effect everything as well.

Kind regards,
Chris

Hi Flemming;
Welcome to the forum--that is one very neat looking engine, well done. A couple of questions--(1) how the heck did you get ' Nanni Ricambi' to respond? the normal comment about Nanni is that it is almost impossible to get that company to respond to people trying to contact them, and (2), can you let us know what carb you have fitted and the jet sizes fitted/--if you would it would very interesting.
One of the difficulties when tuning up the '500' engine and its tuned variants is trying to get carb settings for the tuned versions. thanks for any help you can give.

the hobbler said:

(1) how the heck did you get ' Nanni Ricambi' to respond? the normal comment about Nanni is that it is almost impossible to get that company to respond to people trying to contact them

Click to expand...

I found this amazing as well - every time I've contacted these guys I hear nothing back, so I've largely given up and source my parts elsewhere. Shame really as they seem to stock good gear.

Chris

I ordered on Nanni web page and the next day I received an order confirmation, I sent him some emails and have always had an answer right away, I have purchased from him 2 times and when I had made a bank transfer went there 3 days then came parts with the carrier.
Carburetor from Nanni is a Weber 28 IMB, jetdysse are size 50, I have trouble getting it to work properly and is therefore saving up for a Weber twin choke kit from Nanni but are unsure about what size I should buy, it is available in size 32, 40, 45 and 48 mm.

Evening Bredekilde;
Thank you for your information regarding your carb jet size---I think though the jet size you have given is the 'idle jet'. On the 126 (650cc) engine in the back of my 500, I have a standard '28' carb with a 45 idle jet and a, slightly larger than standard, 117 main jet (at the bottom of the float chamber) Be very careful at to what size carb you fit--it would be very easy to spend a lot of money on the wrong carb. Generally speaking, the '650' and '695' engines require a 32mm size carb.
There is a very interesting web-site (albeit Solex) on how to determine the correct size carb; try looking at :- oacdp.org/solex.html. Another site giving some very interesting alternative (bike) carbs is supplied by 'Blitz Racing' They are very experienced at tuning the 126, 650cc engines. Try:- 'Blitz racing tuning fiat 126 engines'. It is a 'fiat 126 forum' site, but is full of very interesting information and advice. Hope all this is of help:bang:

Flemming,

Before you spend a small fortune on a twin choke carburettor (eg: Weber DCOE or Dell'Orto DHLA) consider that to get the best performance you will need a twin port head (eg: Panda 30). Fitting this head entails some minor engine work and significant panelbeating of the tinware. The carby will also need to be isolated from vibration to prevent fuel foaming and poor running.

If you are going to use a siamesed (2 -> 1) inlet manifold you should reconsider the twin throat route and buy a good single throat carburettor (eg: Dell'Orto FZD or an SU). The head needs no modification, the tinware fits and the inlet manifold is much simpler.

Dell'Orto FZD kits are available from Italy and listed on Italian eBay (http://www.ebay.it/sch/i.html?_trksid=p2050601.m570.l1313&_nkw=dellorto+fzd&_sacat=0&_from=R40). They are not cheap (~450 euros for carby, manifold and air filter) but they are excellent carbies and once fitted and tuned they perform very well. You will get about the same performance from a twin throat carby but use heaps more fuel to do so.

The engine in my car is a 695 with raised compression, sports cam, big inlet valves, electronic ignition and a 32/28 FZD and it goes very, very well. I did a lot of research prior to parting with my hard earned cash and in general I found that those owners who had fitted DCOEs spent a lot of time getting them to run satisfactorily. Don't get me wrong, DCOEs are fantastic carbies and work brilliantly on engines set up for them (eg: twin cam Alfa motors) but are tricky to get right on our air-cooled twins.

Rebuild kits and tuning components (jets etc.) are available for the FZDs.

The first photo was an early trial fit and the second photo is the current installation.

Just my 2c,
Chris

Thanks for the reply, I'll try if I can find a Dell'Orto FZD 32/28 on eBay. Is there a dealer where you can buy a new one, I can see that many of them on ebay are used. Regards Flemming

You may find a NOS carby, but as far as I know they are not manufactured any more so they will all be secondhand items. Mine was very clean and looked like it had never been used even though it was secondhand.

Even when new they were never installed by car manufacturers on their stock engines and were always aftermarket additions. They were a favourite of Mini tuners who bolted them on in pairs.

A cheaper alternative would be an SU and there is at least one member on this bulletin board who has successfully fitted an one though at the moment I can't remember who it is

Chris

I have seen this on ebay.it, price 400 euro. If I win the auction do I need a little help to lull sizes. Regards Flemming

Good luck with the auction. These are expensive carbies but you won't regret it if you win.

Components can be purchased from -

http://www.dellorto.co.uk/merchandise/products.asp?CategoryID=1&PartsectionID=80

I've attached the schematic (pdf) as well as an English translation (doc) of the components.

I will also find the final list of jets etc. that I used in mine.

Finally, I fitted a proper foam air filter rather than using the trumpet.

Chris

Chris; I think that you are spot on! Whilst twin-choke carbs may look cool (to some), it has always struck me as more than a shade mad to bolt onto the top of an engine a carb that is almost as big as the engine itself, especially when the optimum choke size for the 650/695 engines is 32mm! The FZD
Dellorto is a 1st class carb but sadly, unless you are very lucky, it is attached to a ball tightening price (and I am led to believe that when one presses the 'to pay, go' button other parts of the anatomy are known to tighten as well!). If Flemming sticks to the standard 'siamesed port' cylinder head, I reckon the DFZ would be a much better proposition than a 'twin-choke; darn near as powerful, easier to set up and more economical.
I am the person contemplating fitting a SU carb (HS2) to my 500 (650). The HS2 is a 1-1/4 inch (31.75mm) semi-downdraft (same 20deg angle of fitment) with an identical flange layout as the FZD, and as you have mentioned the FZD was often a straight 'bolt-on' replacement for the HS2 when tuning BMC 'A' series engines. When I have my warmed-up '126' 650cc engine (bigger inlet valves with hard seats, fast-road cam electronic ignition and sports carb) running correctly, only then will I proceed with the HS2---only ONE thing changed at a time--ever! I have all the carb bits that I require, but still have to some research on jets and needles.

I actually purchased a dual Stromberg 125CD used carb set to try and fit one of them to my engine when finished. These were popular on Imps and Minis.
These are 32mm also (1.25 in.).
John

I won the auction (400 Euro) on ebay.it and used the waiting time to rebuild the airbox, I have mounted the new carburetor and ran a ride in the car and I must say it runs fantisk, it is very fast on the gas. I do not know what jet sizes fitted, I must have it separate and have ordered the correct sizes and a prober air filter Ramflo. Hilsen Flemming

Welcome to the wonderful world of FZD ownership.
I knew you wouldn't be disappointed.
Chris

Thank you Chris , I will neet your jet sizes

Hi Flemming,

My FZD is equipped with the following -

Main jet 128
Idle jet 38
Pump jet 45
Air corrector 190
Emulsion 6747.6

The pump jet is as close as I could get to the recommended 40 which is no longer available.

The car starts easily without using the choke, idles smoothly at ~800rpm and pulls cleanly without hesitation. Power output is about 33-35bhp at 5500rpm with fuel economy of ~ 6.7L/100km (~ 45mpg) for city driving.

Your engine might be in a different state of tune to mine but it sounds as though your carby is close to optimal at present so you may not have to fiddle too much. Unless to wish to race the beast, the above settings should suit.

By comparison, my engine has the following specs -

695cc
CR ~ 9:1
34mm inlet valves with 29mm exhaust
43/77 camshaft
123 ignition on standard 0 advance setting
Dell'Orto FZD
Abarth style twin pipe exhaust
Alloy rocker cover
3.5L alloy sump

I could probably make it go quicker but my intention was to use it as a small city car. It certainly keeps up with the local traffic in town.

Hope this helps,
Chris

Thank you , I will write back when I find my jet sizes Regards Flemming