General 850 conversion

[Alfatwo]

Ive just started work on a 850 conversion on behalf of a customer.......
Ive modified the heads,big valves,high compression ratio etc, Crank balancing by a specialist, It has a large downdraft Dellorto carb and manifold,oil cooler kit from Middle Barton.
Has anyone been here before?........ most of the stuff came from Italy
Should rev to around 7000rpm before It goes bang!
Any extra info would be most appreciated.............

 

[oopsadaisy]

Hi Alfatwo and welcome.

Can you clarify please..... are you fitting an 850 (assume Fiat 850) engine into a 500?

Sounds an interesting project!

 

[Alfatwo]

Hi Alfatwo and welcome.

Can you clarify please..... are you fitting an 850 (assume Fiat 850) engine into a 500?

Sounds an interesting project!

No this a two cylinder air cooled motor
The oversize pistons and barrel's came from "Nanni" in Milano, there was a huge amount of machining and design work to get them to fit the original 650 block.
My brief is to try and achieve a reliable road going 45-50bhp, (120mph) I know it dosent sound much but thats over double the original 650s bhp

 

[oopsadaisy]

Wow, sounds like an intriguing project!

Won't these mods stress the bottom end?

 

[hudsonhenry]

Ive just started work on a 850 conversion on behalf of a customer.......
Ive modified the heads,big valves,high compression ratio etc, Crank balancing by a specialist, It has a large downdraft Dellorto carb and manifold,oil cooler kit from Middle Barton.
Has anyone been here before?........ most of the stuff came from Italy
Should rev to around 7000rpm before It goes bang!
Any extra info would be most appreciated.............

Assuming that you have forged pistons the crank and rods will be the weak link here. They are very expensive but I would search out a steel crank and titainium or billet steel conrods (Giannini used to use Dino rods).

The standard crank is hollow and not very strong. I'm sure you know, but the other vital thing is to get the whole thing balanced dynamically, its a 360 degree twin so its inherently out of balance. I

Try these places for parts:

http://www.lavazzatecno.it/
http://www.gozzoli.it/

Have a look at my www.retro500.com site if you need some inspiration

Nigel

 

[Alfatwo]

Thanks Nigel, Cracking website way the way