Aussie M20/M21

[craigvk]

Just wondering how I can identify my Aussie 4 speed. I am wondering if it's a M20 or M21. How can I tell without pulling it apart?

Thanks.

[vkberlina]

Yup quite easy to tell

From memory an M20 has 1 ring spun intot he input shaft and an M21 has 2.

A certain way to check though is as follows
An M20 has a 1st gear ratio of 3.05:1 where as M21 has a ratio of 2.54:1
Select 1st gear and turn the input shaft and see how many revolutions it takes to turn the output shaft 1 revolution.

easy

cheers
Scott

[craigvk]

Is that bearing on the input shaft a spigot? If not what is a spigot?

I tried the turning of the input shaft but the output just turned with it. It's out of the motor.

[craigvk]

I hope my Aussie is not broken. :my:

[vkberlina]

The spigot bush is a brass bush that goes on the end of the input shaft and into the crankshaft.

If you select 1st gear turn the input shaft and the output shaft will turn, count how many revolutions it will take to make one complete turn of the output shaft and that will tell you if you have an M20 or M21.

cheers
Scott

[craigvk]

It's turning at a 1:1 ratio. How do I do this? I have the box out of a motor. Is it supposed to be connected to a motor?

Also the pedal box. Why is the pedal boxes I have seen have two pedals on them? Is the clutch pedal and the brake pedal connected to the one assembly? Is the clutch cable the same for a 6 as for a V8? Can you buy it at Autobarn or Repco? How much does it cost? How much does a new clutch plate cost? What's involved with rebuilding the box?

Thanks.

[tigervh]

1. If its turning at 1:1 its in 4th gear not 1st.

2.Its going to be pretty difficult to turn the input shaft with it attached to the motor.

3. The pedal box holds both the brake and clutch pedal, note the 6cyl and V8 use different pedal boxes.

4.Clutch cables are the same for 6 and V8.

5. Any spare parts place will be able to get one in for you. From memory the last one I bought was about $60.

6. The first thing to do if your going to rebuild a box is to get yourself a good workshop manual. It will explain it for you in depth.

[craigvk]

Thanks for that. It looks like it's an M20. Does the trimatic speedo cable fit this box? The speedo hole looks about the same size as my trimatic one from memory.

[tigervh]

The speedo cable will fit