Opinions and experience needed please - to 5 speed - or not to 5 speed?
Building gearbox this week.........will I quickly regret not paying £500 for an "overdrive" 5th?
Will it really make it more useable?
Cannot make up my mind......I've bearly driven my car before I fit a 40 H.P. engine next month - will it run out of revs with just the 4 speeds?

Do it....! In my opinion it is the best modification you can make to a 500 if you have at least a 650 engine.
I have been using Nanni 5 speed conversions in both my daily drivers over the last 10 years and they transform a 500.
If you have any plans to use the car on a motorway regularly it makes a massive improvement - both of my 500's will cruise at a true 110km/h all day long without any risk of breaking a crankshaft and will wind out to 130km/h+ with a standard 650 engine and 125/12 tyres.
Prior to the 5 speed conversion the engine would get very busy at 110km/h and valve bounce would prevent much beyond 115km/h even downhill.
My only caution is if you are planning to use a 5 speed make sure that you choose a cam that allows some mid-range torque and don't lighten the flywheel too much- I did have the 5 speed conversion in previous 500 with a twin choke side draft weber, lumpy camshaft and very light flywheel- it was hopeless as it simply didn't have enough torque to pull the 5th gear on a slight incline and was actually quicker in fourth.
With a standard 650 it will pull 5th from about 60km/h and the higher gearing significantly reduces the noise levels and improves the mechanical longevity of the engine- well worth the investment!

I'll be running 695cc, Dellorto FZD 32-28 carb, 35/75 cam, 36mm inlet valves (with porting etc.) and 500 flywheel - how's the torque with that setup?

It all depends on what you want from the little car. It will obviously allow you to drive a little faster at lower revs which will be better for the engine and make it easier to drive amongst modern traffic. However remember these cars weren't designed for this extra speed, so if you do then make sure you update the brakes as you will need to stop faster than you can accelerate.
Amongst other considerations, remember this vehicle was not designed for high speed crashes. WARNING: you could die.

I used to modify Minis and fitted mine with a turbo charger. It was very quick and kept up with a Sierra Cosworth to 90mph. However I modified brakes, suspension & fitted a roll cage. It was scary but fun to drive, until I lost it at 90mph, hit a bank, flew up in the air and rolled it about 10 times into a muddy ploughed field. That kind of accident makes you think about life!

this one?
http://www.fiat500sport.com/gearbox...-speedand-overdrive-for-126-gearbox-0112.html

or this one?

https://www.fiat500ricambi.com/fiat500/Gear+box/VB1101

Sure thing Sean......just want to have a useable machine......not something that is too limited in its uses.....
Home made disc conversion being considered - can buy a kit ready done for £500 but it can be done with imagination with brand new calipers and discs for £200....or recon calipers for £100.....
Gearbox first.....(current box is seized....)

I've found this at less than £400 delivered

http://www.ebay.co.uk/itm/KIT-5-MAR...504?pt=Ricambi_automobili&hash=item4d1fddb1f8


good enough?

Hi Andrew,
Your setup sounds good- I wouldn't go any lighter than a standard 500 flywheel
I can only speak for the Nanni kit- both of mine have been reliable- bear in mind however these are not bolt-in kits. There is quite a lot of machining involved in fitting these components plus the instructions for the Nanni kit are in Italian and somewhat disjointed.
I don't know how you will go purchasing out of Nanni- they won't ship outside EU and I had all sorts of problems purchasing from them- took me 18months to finally get the kit to Australia.
Still worth it in my opinion...

machining - oh - thats not made clear anywhere in the sales pitch.
I thought that a new housing bolts on and Bobs you uncle.
....can you give me an idea of whats involved please....

Ah yes... the things you find out after you make the purchase!
You will need to machine down the 2nd gear selector sleeve and speedo drive gear. Bear in mind these are hardened and will not just cut with normal cutting tools either.
There is also some modification required to the selector forks too- this can be done with a bench or angle grinder.
I suspect all the kits will be the same as none of them seem to include the speedo drive gear or hub.
With the Nanni Kit it includes the cluster gear but no first driven gear so you will need to buy this separately as it will almost certainly be worn.
Also you will need to modify the reverse lockout in the gearshift assembly by cutting a notch out of it so that you can select 5th without having to push the lever down.
Otherwise it is all pretty straightforward really!

Well I've ordered it now......looks like fun installation ahead!
Many thanks for all your help guys.

Andrew

Good thread as I'd been wondering about this as well. My question is whether this upgrade can be done on the non-synchro box or whether the synchro box is a necessary starting point? I don't really want to lose the non-synchro box as that is part of the charm.

J

the Nanni Ricambi item above offers a separate kit for 500's - so I'm taking that yes you can have a 5 speed in a non syncro box......
My kit arrives today - and off to machine shop Friday - I will attempt to indicate what works are required.

The 5 speed conversion will fit either transmission- the only reason why Nanni list a different kit is because theirs comes with a mainshaft (cluster gear) which is different between the 500 and 126.
The 5th gear uses a dog clutch engagement anyway so for the purists who don't want synchromesh in their gearbox conscience will remain clear....
In my opinion you can still double clutch the synchro box if you feel that way inclined- the synchro in a 126 box is very quick to engage and driving mine in traffic everyday I would personally not go back to the dog box again...

So the kit arrived - and the case is damaged - bugger!
It came in a plastic bag and not in a box and the nose of the casting is heavily dented where the gear selector shaft exits - and the oil seal is mis-shapen. New one demanded from vendor.
The kit itself is of good quality - the only question is with the ali case.
The bush the selector rod exits is steel - and i'm minded to change it to brass when I'm machining parts - what do you guys think?

I've got the parts ready for machining 2nd gear syncro selector sleeve and the speedo drive - shouldn't give my machinists too much trouble - they will do this whilst also machining the cranckcase.

AndrewHarvey said:

So the kit arrived - and the case is damaged - bugger!
It came in a plastic bag and not in a box and the nose of the casting is heavily dented where the gear selector shaft exits - and the oil seal is mis-shapen. New one demanded from vendor.
The kit itself is of good quality - the only question is with the ali case.
The bush the selector rod exits is steel - and i'm minded to change it to brass when I'm machining parts - what do you guys think?

I've got the parts ready for machining 2nd gear syncro selector sleeve and the speedo drive - shouldn't give my machinists too much trouble - they will do this whilst also machining the cranckcase.

Click to expand...

That's bad news- but I have to say I'm impressed how quickly you managed to get it- mine took over 18 months but at least arrived intact!
Personally I think the selector bush is fine- after 10 years of daily use mine still doesn't have any play or leakage.

That's a real bummer! I never understand why companies don't protect products when they are being posted.
I had 3 massive boxes with all my panels delivered by Motobambino and everything was bubble wrapped & protected with cardboard. I didn't have one item damaged.
Hopefully they will sort it out for you Andrew.

Hi - does anyone have an English copy of the build instructions for the 5 speed conversion?
My Italian translated version takes some effort............

Is the severely expensive 5-speed shift plate REQUIRED for a 5-speed conversion to work? I don't recall seeing what the 4-speed plate looks like, if there is one. Can that just be machined to allow the 5th gear slot?

is there anyone who's carried out a five speed conversion able to assist in information please?
:bang: