How do we identify a gearbox?

[Ian65]

Is there any way to identify which gearbox comes out of which model?
ie. s1, s2, s3.
I have 3 gearboxes and they all look identical, 2 came out of s3 cars but both cars had had engine swaps at some time in their lives and the other is definitely S2. Externally, all 3 boxes look the same.
A strange thing is that all 3 engines / boxes were running 215mm clutches, even in the S3\'s.

[CHC (RIP)]

Could it be that the designers and engineers did such a good job with their 1st production model that they found no reason to make modifications?

[mpk490p]

i believe the speedo drive is a different color when removed although i couldn\'t tell you what colour matches what year

[Ian65]

i believe the speedo drive is a different color when removed although i couldn\'t tell you what colour matches what year

yeah, there\'s a good write up on speedo drives here...

http://www.solomiata.com/Drivetrain.html

apart from the speedo drive though, the boxes look the same to me although s3 boxes are supposed to be stronger?
I think I have 1 no s2 box and 2 no S3 boxes from what I can work out.

[David Nock (RIP)]

I deffo took a green, 17 tooth speedo drive from an S2 box for Steve-A. It was  a 2 second job for Grommit to unfasten it.
It was said on here in Steve\'s post that the S3 gear was no good....black 19tooth.

I also have some remaining memory cells which still contain information read somewhere.....oh what information....    Ah, Remember now.....Mazda had raised the oil level in the S3 box due to starvation of the 5th gear on Motorways. True or not? I certainly read that. So the plug should be higher.

Also 225mm is the clutch size for S3....
Again from reading material back in the mists of time, the transmission was breaking on the earlier cars, so Mazda beefed it up. Looks like that might be a contributory factor Ian? Someone\'s fitted a smaller part in the past.

[Ian65]

that\'s a good point about the oil plug.... I\'ll check that.
I think the speedo drive is a way to date the box but until you pull it, it\'s difficult to tell.
I think Mazda also uprated some of the internals for the S3 model years but again, you can\'t tell from the outside.

I don\'t think the clutch diameter contributed much to its breakup, I think it was more down to the previous owner abusing and thrashing the car ( as evidenced by it\'s condition when it was taken off him) and weakening the clutch to the point that the 1st time I really gave it some stick, it just disintegrated.

The 215mm clutch plate was used by Elford to put out 165bhp and this conversion was officially sanctioned by Mazda UK who still honoured the manufacturers warranty on the turbo\'b cars, so they must have been confident it could cope with the power.
It does seem strange though that Elford ran with the 215mm clutch yet when Mazda launched the S3 they upgraded the clutch?
I wonder how many S3 cars are running around with a 215mm clutch in them?

[myatt1972]

I wonder if the clutch plate was made larger to help it last longer rather than taking more power ?

[Ian65]

I wonder if the clutch plate was made larger to help it last longer rather than taking more power ?

I was reading an article in the e-book where they were writing about clutches and Elford stated that it was just down to the individuals driving style how long they lasted. 1 clutch had done 100,000 miles, another was burnt out after 30,000.
I would have thought what you said yesterday was right, that you\'d want more friction area for the more power you\'re putting through it, although, as we said, Elford didn\'t upgrade the clutch.
I reckon you could still burn out a 225mm plate quicker than a 215mm plate if you thrashed it hard enough.

I really don\'t know what the answer is, I\'m still trying to get my head around it all.
It\'s interesting though to read everyones views and thoughts on it!

[myatt1972]

Mazda\'s B series pick ups seem to have the same clutch kit and the slave looks very similar, have a look on e-bay and see what you think
Also looking at clutch kits for sale in the states the non turbo 13B kits are the same as 12A S3 kits, 225mm 22 spline.

[myatt1972]

I also have some remaining memory cells which still contain information read somewhere.....oh what information.... Ah, Remember now.....Mazda had raised the oil level in the S3 box due to starvation of the 5th gear on Motorways. True or not? I certainly read that. So the plug should be higher.

Had a look today on an S1, S2 and S3 gearbox. The oil level plug was lower on the S1 box, so your brain cells were almost right but looks like the change was S1 to S2.

[Ian65]

Had a look today on an S1, S2 and S3 gearbox. The oil level plug was lower on the S1 box, so your brain cells were almost right but looks like the change was S1 to S2.

Doesn\'t the S1 box have additional switches on it as well?
I thought they had switches that knocked out part of the ignition in 4th and 5th? ( the ones that some guys wire to the e-fan)

[myatt1972]

Not sure Ian, will uncover it properly tomorrow to have a look.