Technical 1.2 16v 86hp 176B9000 gearbox compatibility

[Seatpanda]

Hi all, I own a 1980 Seat Panda with this engine and gearbox swap.
As I use offroad wheels (bigger diameter), the gear ratio is a bit long, I always end using first and second gear on the country-side

Any idea how can I reduce the gear ratio on this gearbox? is there another Fiat gear box I can use with this engine?

Thanks!

 

[Frank Folker]

if you have enough room to fit a 6-speed c514, one from a mk1 punto 6speed has a very low gearing (1:4.9 final reduction). Everything bolts up the same, the box is just longer and it is only a question of having enough room for it.
Lancia Y (840) 6-speed has the same final, 1st and 2nd gear ratio as the 6-speed Mk1 punto but the upper gears are more "spread out". Still a good match for your needs.
The Mk2 punto sportings 6-speed have a more "civilized" 1:4.071 reduction, so you don't want that.

Your gearbox has either 1:4.071 final if it came from a sporting or 1:3.733 if it came from an elx or sx punto. No 5 speed box (that I know of) has a gearing as low as the 6-speed from a mk1 punto.

Final drive can't be easily changed as the pinion gear is one piece with the secondary shaft. You could disassemble boxes completely and transfer shafts (and use correspoding diffs) but that's a lot of work and you still can't make a very short 5-speed box as the 1:4.9 final was only made for 6-speed boxes (longer shaft). Bacci Romano makes secondary shafts and diff crown gears with custom ratios (very low, up to 1:6) and sells those sets for around 1100 eur. I think both 5 and 6 speed versions are available.

 

[Seatpanda]

if you have enough room to fit a 6-speed c514, one from a mk1 punto 6speed has a very low gearing (1:4.9 final reduction). Everything bolts up the same, the box is just longer and it is only a question of having enough room for it.
Lancia Y (840) 6-speed has the same final, 1st and 2nd gear ratio as the 6-speed Mk1 punto but the upper gears are more "spread out". Still a good match for your needs.
The Mk2 punto sportings 6-speed have a more "civilized" 1:4.071 reduction, so you don't want that.

Your gearbox has either 1:4.071 final if it came from a sporting or 1:3.733 if it came from an elx or sx punto. No 5 speed box (that I know of) has a gearing as low as the 6-speed from a mk1 punto.

Final drive can't be easily changed as the pinion gear is one piece with the secondary shaft. You could disassemble boxes completely and transfer shafts (and use correspoding diffs) but that's a lot of work and you still can't make a very short 5-speed box as the 1:4.9 final was only made for 6-speed boxes (longer shaft). Bacci Romano makes secondary shafts and diff crown gears with custom ratios (very low, up to 1:6) and sells those sets for around 1100 eur. I think both 5 and 6 speed versions are available.

Hi Frank! Thank you very much for your reply. Can’t find much info about these gearboxes, your help is much appreciated.

How much longer/bigger is the punto mk1 6 speed gearbox compared to mine? Mine is literally touching the side of the car chassis, not sure if I can put one longer.
I don’t understand well these gearboxes numbers on their cases, this is my box:

Which box do I have? Sporting 1:4.071? or 1:3.733?

 

[Frank Folker]

Sorry but I don't know them by numbers, you will have to try searching the internet or resort to measuring yourself somehow ☠
One method would be to lift one front wheel up, put it in 1st gear, turn engine over using a wrench on the crank nut and see how many circles you need to turn the engine for for 1 revolution of the wheel. If it's 7.3, then you have a 1:3.733 final (3.733 x 3.909 / 2). The division by 2 is because one wheel is on the ground (not turning) so the diff doubles the speed of the other wheel. If it's 8 turns, you have a 4.071 final.
This is just an idea, if it's too hard to turn the nut with the wrench, don't break it. I think it's just a 13mm nut.

Below is a photo I found online (not my photo). On the left is a 6 speed box, right is 5 speed. Ignore the different looking mounts, you can just transfer that from your old box. I added arrows where the difference in length is. 6 speed has a long aluminium cover, 5 speed just has a stamped steel cover. Lenght difference is about 5cm

 

[Seatpanda]

At the moment my car is on easels and both drive shafts are out for repair, so I can't find out if my gear box is 1:4.071 or 1:3.733
I have been doing a bit more of research, spoken to a guy here in Spain who "apparently" has open lots of these gearboxes and says:
1:4.071 secondary shaft and diff crown gear is a 14/57
1:3.733 is a 15/56

And the best is, he says I can install Fiat Panda 4x4 secondary shaft and diff crown gear which is a 11/60
looking at this website: https://spicerparts.com/calculators/gear-ratio-calculator
Mi final gear ratio will be 1:5.4 which I think will be quite Ok for the use I give to the car, he can even said can install a longer 5th gear and will do everything for 250€ I am tempted to try.

 

[Frank Folker]

that sounds like an excellent option! I didn't know about panda 4x4 having so short gearing