Clutch pedal question, Arm length? Options

[GeorgeRud]

I converted my car a few years ago to a 915 transmission, with a 74 release fork. I find that the clutch pedal has to be pushed all the way down to release the clutch (yes, the free play is correct). I was told that there is a difference in the length of the clutch lever arm length on the pedal assemblies between different car models (911 vs 914). Does anyone have any experience with this? I'd love to shorten the pedal travel, though I realize it will increase the pedal pressure needed to release the clutch.

If anyone has a picture with the measurements, I'd love to see it. I can remove the pedal assembly, replace the bushings, and try to modify the arm at the same time.

[Larry.Hubby]

I also have a 915 box in my car, although I stuck with the '78 clutch release mechanism. There are several differences between the stock 914 cluth pedal shaft and the one for the 915 box. One is the length of the arm that pulls the cable, the release arm, as you observe. Unfortunately, the angle at which the hole for the roll pin that anchors the pedal to the shaft is drilled is different on the 911 part, as you can see from the photo:



Here, I've just put a long 6mm bolt thru the holes for the roll pin on both shafts and you can see the difference in the angle. If you just install the 911 shaft in the 914, the release arm will be rotated too far forward and the amount of pull you will get on the cable will be reduced. You will get more travel than with the 914 shaft, but still not enough, at least with my setup, and the clutch will still engage uncomfortably close to the floor. I wound up making a new clutch shaft with the angle of the hole corrected:



There is also one more difference. The 911 shaft is longer, moving the release arm further toward the center of the car, in order to keep the release arm from interfering with the throttle relay lever, so a plastic spacer is used to take up the space between the release arm and the end of the tube that holds the bearings for the clutch shaft. Since my revised clutch shaft has a straight, rather than a bent release arm, as you can see in the photo, I had to make a longer spacer also. Once I installed the revised shaft, the clutch operated normally.

Hope this helps.