Clutch Fork Ratio
 

Hey guys, so I have a small problem here. I've been in the process of installing my double cheeseburger tilton clutch and have run into a problem. I measured the install height of the stock clutch and tilton clutch and it matched up to what I needed. However, when I buttoned everything up the clutch didn't disengage.... DOH!! This sucks. I bled the clutch hydraulics and there is no air in there. I adjusted the clutch pedal to what is specified with that 1/4" - 1/2" play on the pedal. I tried to adjust it further so that there is almost no slack and this worked a little. I could get it into first and second, but with a lot of effort. So this is my question, what would happen if I increase the length of the pushrod at the clutch slave cylinder without shortening the knob thing inside the transmission that the fork pivots on?

This might help you...

http://forum.miata.net/vb/showthread.php?t=243177

Hmm, sounds like that if I have the 7.25" (which I do) I shouldn't be running into this problem. I remember reading about y8s installation before and inquired with him and found out exactly what mods he did. Since I measured the installed heights and it came out to be the same I thought I would've been good, apparently not. Dammit. I guess i'll have to take out the tranny again to see whats goin on. I was hoping that I could just increase the travel on the clutch fork to disengage the clutch.

Ahh, I didn't know which diameter setup you had. Sorry!

Oh not a problem! I really appreciate the help. At least now I know what I would have to do with a 5.5" setup. hahaha

Keep in mind that it takes just the smallest amount of tolerance to fully disengage a clutch. So you could literally stick a washer on the end slave rod (between the fork seat) and at least see if it helps.

I'll give that a try before having to take the tranny out. I did everything while the motor was out since I had to change motors to rebuild one.

Any other suggestions will be greatly appreciated! I will try everything before removing the tranny.

did you make a shorter pivot and a longer push rod both?

did you install the disks so that the hub was away from the transmission?

if you had a hard time getting the tranny that last half inch and cranked it down with the bolts, you might want to preorder a replacement disk.

y8s: I did not make the shorter pivot and longer push rod since the install height was the same as my stocker. I installed the disks per the tilton instructions. I purchased the clutch from neogenesis and he had a 1.6 flywheel machined to work. He told me that everything was set up, however I must check the install height of the clutch which came out to the same as my stock 1.6. Therefore I assumed that I didn't need to shorten or lengthen any of the pushrod/pivots.

I did have a very hard time getting the tranny that last half inch and cranked it down with the bolts. =( I'm guessing that the clutch disks were installed wrong? Was I supposed to install it reverse from the tilton instructions? Dammit!!! FML

Its a good thing I have two extra disks...I guess I have to remove the tranny and reinstall everything.

Could you please explain to me why that needs to be done? Does this mean that the input shaft of the transmission got hung up on the hub of the clutch disk closest to the tranny?

oh he/you used the 1.6 flywheel...

I can't really say if it's the disk hubs hitting the input shaft boss or not since the overall height is lower. mine was too tall so I had to flip them around backwards (opposite of tilton's instructions)

my disks hubs are offset enough to make them not clear that boss that the release bearing slides on.

potential bad news: if you did do this, it may have mushroomed the soft aluminum of the tranny boss and you wont be able to get the release bearing off without de-shrooming it.

one test you can do is to back the tranny bolts out 1/4 inch and see if you can disengage and if not, back them out another 1/4 inch and see.

it will be very evident if you did hit the clutch disk with the boss because both should show signs of wear (assuming you had the motor turning enough to mess them both up)

BITCH!! This sucks ass. When you say the tranny boss, I'm assuming input shaft since thats what the release bearing slides on?

I'll check it this weekend...hopefully I can get some pics and post it up so you can see.

Yenno what, now that I think of it...I had the 1.8 flywheel and stock clutch on my 1.6 motor. The install height was the same. Which means that I was supposed to install it opposite from tiltons instructions...FML I hate my life right now.

yeah the thing around the input shaft:

http://gallery.y8s.com/d/823-3/DSC02561.jpg

So I figured out the problem. No shrooming of the input shaft, no damage to the clutch plates or pressure plate, just too long of a stroke. I hope no damage was done to the spring. It looked fine, but I remember reading a warning about over stroking it. So the fix was to adjust the clutch pedal so that there was about .5-.75" or freeplay. Now the clutch engages halfway up the stroke. I didn't get to drive it yet cause my brake booster is out to get some fresh por15. I'll report back when i get a chance. Thanks everyone!

nice. i love it when problems can be fixed without pulling a trans.

just curious how the 1.6 flywheel works with the 7.25? How does it bolt up? what is being machined?

The 1.6 flywheel must be machined in the front facing the transmission to reduce the install height of the clutch. A step of 0.1" (i think) must also be machined into the face where the clutch disc will contact the flywheel. You will also have to drill and tap new mounting holes for the pressure plate. I hope I got that right. Sorry but I don't have any pictures of the flywheel.

sounds right. the .1 step height is correct.

If you haven't already resolved the issue, I had a similar problem with the 949racing twin plate, ended up being a clutch disc getting stuck on the spline as the tolerances were a little too tight out with the file and a little clean up fixed that good and proper :)

Hope that helps, I used a plastic alignment tool and needless to say it sucked.

EDIT: Helps to read the posts, looks like you solved the problem, but ill keep this post in case someone does a search and runs into a similar issue to me.