Tuning Classic Fiat 500 Period correct Mods.

[Ziffa]

Hi Guys and Girls.
So, I'm sitting at my laptop, scrolling through an assortment of sites, articles and google images, and something crossed my mind... there are A LOT of aftermarket mods you can do nowadays, but what about the mods that were done back in the day? I'm extremely curious about what was done, for example, banding original, steel rims, swapping carbs, weight reductions, grinding away some weight, and swapping parts from other cars onto our beloved 500s.

One that I've heard of is that VW super-beetle cylinders could be installed on a machined engine block. The Guy who told me about it, said that he would be able to keep up with mini coopers... when the axels wouldn't snap.

I look forward to hearing what you guys have to offer.
TiA.

 

[Toshi 975]

One of the earliest carb swaps using production parts was to fit a Weber 30DIC twin choke carb from an 850 Sport Coupe or Spider and an Alquati inlet manifold, copies of which are still available. Another very popular carb choice was the Dellorto FZD which I believe was designed for the Innocenti Mini then proved to be very successful on tuned Fiat engines with a suitable manifold.
There are engines in existence that have the VW piston and barrel conversion which I believe gives you 804cc and as you say it requires machining to the crankcase and also extensive cylinder head work. There was also the Alquati 795cc kit which you can still get, Ricambio have the kit at a little over £1,000 and also requires a lot of engineering.

 

[the hobbler]

One of the earliest carb swaps using production parts was to fit a Weber 30DIC twin choke carb from an 850 Sport Coupe or Spider and an Alquati inlet manifold, copies of which are still available. Another very popular carb choice was the Dellorto FZD which I believe was designed for the Innocenti Mini then proved to be very successful on tuned Fiat engines with a suitable manifold.
There are engines in existence that have the VW piston and barrel conversion which I believe gives you 804cc and as you say it requires machining to the crankcase and also extensive cylinder head work. There was also the Alquati 795cc kit which you can still get, Ricambio have the kit at a little over £1,000 and also requires a lot of engineering.

How far back do you want to go for "in the days"? When I worked at 'Radbourne Racing' in the very late 1960s. we enarged the engine capacity of the 500 engine (the 126 was not to come out for some years) to 652cc by fitting "Nardi" kits (which, I was led to believe, DID use re-machined VW barrels) which comprised of barrels, pistons and camshafts. You COULD get kits from Abarth (VERY expensive!) or from Gianinni, another first-class tuner of the 500 engine. When Abarth went up to '695cc' he only increased the bore to76mm, and in order to bring it up to 695cc he also fitted a 76mm CRANKSHAFT. This is because it is not wise to enlarge the 500 crankcase (engine type 110) to accept bigger barrels than those with a 77mm bore. Fitting this size barrel requires the barrel apertures in the crankcase to be machined out to 83mm---machininng it our any more will (a) risk losing stiffness to the crankcase and, (b) completely remove the 'bottom-of-barrel-seal-lip' that is cast into the crankcase. The 126 crankcase is much more able to take the larger barrel sizes.
David (Toshi) mentioned the 'Dellorto FZD'carb---these are a very good carb for the 500 and 126 engines---simple, easy to fit, reliable, they stay in tune and the manifolds to fit these carbs onto the 500 are widely available, as are the carbs (in Italy mainly). The 24/30 FZD would be a good choice for you engine size, and I would be able to help you with regard to suggested jet sizes---at least as good 'starting point'. Nearly ANYTHING is possible if you have the time AND the money---they may be small engines, but they are not that cheap to tune. Having an engine that produces (relatively speaking) a lot of power but also probably needs a lot of constant TLC, is not always the wisest way to go, but your money---your choice!

 

[Bigvtwin996]

yes you can fit vw cylinders and even Dino Con rods big weber cars super sports exhaust even ohc heads and a sequential gearbox and LSD, and have a car that becomes almost undriveable and a pain to live with, or you colud leve it as is and buy a Fiesta St and keep the fiat for driving calmly and sedatley and have people looking and smiling rather than saying "what the FFFF is making that noise"
bu a few simple mods - few extra ccs a better cam and carb with a better but not noisy exhaust, would probably be nice

 

[the hobbler]

yes you can fit vw cylinders and even Dino Con rods big weber cars super sports exhaust even ohc heads and a sequential gearbox and LSD, and have a car that becomes almost undriveable and a pain to live with, or you colud leve it as is and buy a Fiesta St and keep the fiat for driving calmly and sedatley and have people looking and smiling rather than saying "what the FFFF is making that noise"
bu a few simple mods - few extra ccs a better cam and carb with a better but not noisy exhaust, would probably be nice

Strange that Peter (Bigvtwin) should mention "Dino" con-rods, as believe it or not, they fit the 500/126 engines with very little modification. The journal dimensions at both ends of the "Dino" con-rod are exactly the same as that of the Fiat, and it is only 1mm shorter than the standard Fiat 500/126 con-rod, not a difficult problem to overcome. The only bit of 'fettling' required is to the inside of the crankcase to give the "Dino" con-rod clearance.
I once found 6 x Dino conrods for sale in America, and, along with a colleague of mine, we tried to buy them---sadly, we just missed them.The company who had them for sale 'inherited' them with the company that they had just bought, and had no idea as to why the 'bought-out ' company had them in stock---then they told me the name of the company that they had just bought----it was a company that had been an "Abarth" dealer, in the days of 500, 600 and 850 based Abarths. They were VERY surprised once I had enlightened them! The contact wasn't a complete waste of time as i was able to buy a couple of the books(catalogues?) produced by Al Cosentino who WAS "FAZA Fiat" in America.
At one time, when the "Dino" wasn't considered a car worth restoring, 2nd hand "Dino" con-rods were not too difficult to find, but now that a good "Dino" will fetch north of £250,000, they are no longer available; which is a shame, as I would have loved to have a pair of "Dino rods" in my '695SS' engine.

 

[Toshi 975]

Now that you have mentioned FAZA and Al Consentino it reminded me about these original belt buckles that he had made back in the day and were shown in the catalogue . They were only ever sold in the US and Japan but somehow these three unused ones found their way to the UK and I ended up buying them. The yellow one sold last year to a 500 enthusiast but I still have the black and blue ones.
It seemed odd that they sold in Japan until I found out that Al Consentino had a Japanese wife.
As for con rods, not as slick as the Dino but some Fiat 127 rods are the same and I have used two new pairs in engine builds in the past.