Spline size vs spline count?

ASSISTANCE Hybrids & Advanced Aftermarket Engine Performance
1

My car is at the mechanic’s right now going through what I was hoping to be a relatively painless transmission swap. I just got a call saying that the transmission doesn’t match my clutch.

I am aware that there is a difference between 90-92 and 92-93 clutches, but here is where I’m double guessing myself now. Everything I’ve read says that the 90-91 spline is smaller the 92-93. With this in mind, I go and measure the spline off of a known 90-91 transmission with a set of calipers. I lock the calipers so the size doesn’t change and go and look at another S1 transmission that somebody had for sale. Using the calipers, I slip them over back and forth do see if the splines are the same size and it all supposedly checks out. Seeing the S1 label combined with the matching spline diameter, I didn’t even think twice that it would have been anything different. Was measuring the diameter the wrong approach? Should I have counted the teeth instead? Live and learn I guess.

2

edit: i think the difference in diameter is 1mm

check out the integra applications:

http://www.exedyusa.com/race/Applications

3

I see that now. Always got to learn things the hard, expensive way.
1mm difference. I never would have guessed the difference to be that miniscule. I need to throw those fckn calipers in the garbage.
Thanks.

4

I had a 92-93 disk and a 90-91 transmission at hand once, so I know the difference in input shafts is that the 92-93 sticks out far enough that you can’t lay the transmission on flat ground over that shaft, and on the 90-91 you can. That’s where that extra 1/16" for the later years comes in.