Technical Engine changeout for a newbie....yikes!

[Nat514]

Hello,

I'm just about to start pulling 499cc out of my 500 and replacing it with a 650cc. My first attempt at such a large task. Any advice is appreciated!

 

[the hobbler]

What gearbox are you planning to use? I ask this because the 500 bell-housing will NOT fit a '126' crankcase.
Where about are you? It might be that there is a Forum member close to you who could (metaphorically speaking) 'hold your hand' It is not a difficult job, but the 650 engine will come with an alternator, so there will be some wiring requiring changing, the 650 engine will probably have a Weber 28 IMB carb with a fuel-return outlet so you will have to attend to that. How complete is the 650 engine?

 

[Uaglio]

https://www.fiat500club.org.uk/home/installing-a-fiat-126-engine-and-gearbox-into-a-fiat-500/

 

[Nat514]

Thanks for the great advice. The 650 engine is complete and I plan on using the 126 transmission. I'm located in Montreal....if you know of someone nearby, I'm always open to hand holding.

 

[berkeleyman]

If you intend using the 126 transmission then the drive shafts will need to be changed as the 126 shafts are longer

 

[Nat514]

Thanks! This step sounds harder than pulling out the whole engine!!

 

[the hobbler]

Fitting new drive-shafts into a '126' gear-box isn't a difficult job, as long as you go about it methodically. You will only need 3 sizes of spanner/sockets---10mm + 13mm + 17mm. Drain the gearbox first, or you will have a load of gear-box oil over the floor/workbench. I have seen an old stool being used as work-stationfor doing the gearbox---invert the stool, and stand the gearbox up on its end within the legs of the stool. If you want to contact me direct, I will sit down and try and write out a sequence of work for you ([email protected]). Don't forget to refill the gearbox when all the work is completed---with the '126' 'box you can use a high grade 20/50 engine oil (I use Castrol). DRY capacity of a '126''box is 1.1 litres---you probably won't get any more than just under a litre in it on a re-fill. It will be much easier if you have a 2nd pair of hands to hold the gearbox when you are torquing up yhe diff and bell-housing bolts/studs. Lastly, get THE BEST POSSIBLE shafts and couplings that you can--variouse suppliers specify "racing" spec or "top quality"---do NOT get the cheap versions, it is a false economy.