Gearbox / 5th gear ratio for Jr. Zagato 1600

[ZZ_jr]

can any one tell want kind of gearbox should be in a Junior Zagato 1600 and what the ratio is for the 5th gear?

I know that a Junior 1300 according to the homologation papers of 1st August 1970 has a "normal" gearbox typical for late 105 cars but with a close ratio 5th gear with ratio 0,86.
A normal gearbox has standard a 5th gear with a ratio of 0,79.

Is the Junior 1600 shipped with the same gearbox + 5th gear as in the 1300 Junior Zagato?

looking forward to your reply, thanks.

regards,
ZZ_jr.

[Zagato_Olaf]

Hello Frank,

I had a peek in the books and came up with the following information;

In the book 'Le Zagato Fulvia Sport - Junior Z' there are no specific homologation papers for the 1600 Z published.

According to Fusi in his Bible for the 1600 Junior Z:
1st: 3,30
2nd: 1,99
3rd: 1,35
4th: 1,0
5th: 0,79
Final drive: 9/41

For the 1300 Junior Z
1st: 3,30
2nd: 1,99
3rd: 1,35
4th: 1,0
5th: 0,86
Final drive: 9/41

This information is confirmed by the Catalogue Raisonne of Automobilia.
If it was possible to order a different final drive as an option, I don't know!

According to Fusi the final drive of:
a 1750 Berlina is 9/41
a 1750 GTV is 9/41
a 1750 Spider is 10/41 in Europe (9/41 is USA).

What kind of back axle is under your JZ?


I'll check more books for info!

Ciao, Olaf

[Virus Alfa]

Hello

according to the "charatteristiche tecniche..." handbook for the 1600 Junior Z the ratio for the 5th gear 1:0,79 and considering the final drive of 9/41 it is 1:3,603.

Regards, J.

[ZZ_jr]

thanks Olaf & Virus Alfa.

Recently I changed the rear axle with an axle coming from a GTV 1750 (not sure about the final drive) but any how longer then the rear axle standard.
Must be GTV1750 as on the left side the wheels nuts have a left hand thread. Most likely it will be final drive 10/43

Still I believe that the car revs to high in 5th gear; 4.000 rpm = 105 Km/h (real km/h according to TomTom GPS).
If I compare this with my Berlina 2000 that runs about 135 km/h at the same rpm.
Perhaps in the past the previous owner of my car changed the gearbox with a short 5th gear.

[Zagato_Olaf]

Hello Frank,

Curious! I'm not an expert on final drives but I know of ratios with 8/41, 9/41, 10/41 and 10/43. I also know that you could order an alternate final drive ratio on your standard car when purchasing the vehicle from Alfa Romeo. So a 'standard' 1750 rear axle could be something different.

Your conclusion that there is a short 5th gear in the box seems likely. A shorter final drive ratio seems likely as well!

I checked my rpm's today as my 1300 cc engine is back in the car and it's running again! In fifth gear with 1300 cc gearbox
100 km's is 3300 rpm, 110 km's is 3650 rpm.

Ciao, Olaf