Tuning updating from 500cc to 600cc or 650cc

[gordinir8]

As I have mentioned before I want to update my engine to 650 and make little Eddie a 595 replica. I was wondering if it is worth upgrading to a 600cc engine since there is one available that I could buy locally. Is there any great difference in power between the 650 and 600?
On the other hand is there any difference between 500 and 600?
I also like the idea my 595 be real 595 and not 650. Otherwise it will be a fiat 500 converted to 595 with 650 engine!! Doesn't sounds right.
Thomas

 

[fiat500]

I think that a 594 with a 28 carb will be much better than a 499. The 652 has been a massive difference to me, but if you convert from a 499 you have a structurally weak engine, while a 594 is the strongest by all accounts. It's also good to be able to keep the original engine which you can eventually give a full overhaul at your leisure if you want to.

 

[fiat500]

By the way, get the gearbox too or you won't be able to use it. I guess that it's off a 126 so would have synchromesh. The 126 box seems to have a slightly longer final ratio so the car can go faster.

 

[fiat500]

From the Haynes manual for the Fiat 126 spec:
594cc 23 BHP @ 4800rpm.
652cc 24 BHP @ 4500rpm.
Same CR @ 7.5 to 1 except 652 after 1985: 8.0 to 1

 

[the hobbler]

If you are trying to build a '595' replica and you have the chance to buy a '594' engine, I say--go for it! A really well built 595 engine is (if driven sensibly) almost unburstable. In Abarth days the '595ss' actually produced more power than the plain '695'. It wasn't until the 'ss' version of the 695 engine came out that Abarth claimed a higher BHP figure. The bore and stroke measurements of the 500R/Mk 1 '126' are exactly the same as the 'pukka' "Abarth 595". With a nicely ported head (don't forget to ease the ridge behind the inlet valve in the inlet tract), 35/75/75/35 cam, sports exhaust, standard 500 flywheel (if it is 126 engine that you are obtaining--the standard 500 flywheel is 2kg lighter than the 126 flywheel) and a 30/24 Dellorto FZD (or, a single bike carb---Mikuni/ Keihin--manifolds for these bike carbs are available in Italy) you will have a very nice little engine with substantially more 'grunt' than the standard 500 engine. Let us know you decision please.

 

[gordinir8]

I might go tommorrow and check if the engine is still available and at what price. Ofcourse j have to buy a synchronised gearbox also. I believe 500 gb doesn't fit except if you put the 126 housing. Tom all those mods are mandatory for me except maybe for the carburator. I'll let you guys know in any case.

 

[the hobbler]

You will probably find that you can get away with just exchanging the '500' bell-housing on the gearbox with a '126' bell housing (and starter). Even a 2nd hand bell housing will do the job. If you are careful how you take the bell-housing off the '500' gearbox, you will find that you can retain all the diff and bearing adjustments, and then just fit the '126' bell housing.

 

[gordinir8]

I went to see the engine today, not bad in an restored condition but old man is asking 500 euros for it! For that kind of money it is possible to find a 650 along with gearbox so i don't think it is worth.