Rear Axle Keyway Konfusion

[Iamscotticus]

I suppose, those who don't know better, would assume that Marina axles and Ital axles were the same.

But when they are put into the kit cars like Caterham did in the 80s and 90s, we 7ers are more particular.
They put them on the race tracks and beat the snot out of them. Then we have to fix them. This is where we learn the differences in axles, and why we need to know.

I am not planning on racing my Caterham with Ital axle, so Caterham claims that is an 3.64 Ital axle in the build manual, but I will be upgrading the axle to a high spec with LSD and upgraded half shafts, etc. Just to have the best bullet proof axle possible, without going to other, heavier options.

So, here is what I need to know... Do I have a Marina or Ital axle? All I can tell you is the hub key way is 3/16". I thought this was only a Marina thing. So I thought I have a pre 78 Marina. However, I am reading that the earlier 1.3 Itals were not built as stoutly, and had collapsing pinion spacers, and who knows what else? 3/16" hub keys?

Therefore questions arise I need to know like, if I have a collapsing pinion spacer, will a non-collapsing spacer from another Stanpart diff fit in?

@kilroy?
@SteveGreen thanks for the axle technical article, I forgot where I found it.