Moparts

Calculate clutch pedal travel

Posted By: DGS

Calculate clutch pedal travel - 08/07/14 05:26 PM

I want to see how much my clutch pedal travel should be. Are my calculations correct?

clutch disc to flywheel gap: 0.050"
release levers on clutch ratio (long style): 4.8:1
clutch fork ratio: 2:1
ratio between 3/4" master and 7/8" slave: 1.37:1 (calculations are correct as you have to compare the area and not the diameter)
pedal ratio: 6:1

Multiplying 0.050 * 4.8 * 2 * 1.37 * 6 gives me a pedal travel of just under 4 inch (3.95"). That doesn't seem to be a lot..or are my calculations wrong?

how much clearance should be between each part?
Posted By: Sinitro

Re: Calculate clutch pedal travel - 08/07/14 09:12 PM

U are making it complicated with the math..
1st point is to make sure U have the rite Z-bar, the tab that drives the pushrod to the fork so the pushrod should be parallel to the bellhousing. My Roadrunner had the wrong Z-bar creating incorrect and harder leverage. There are (3) different Mopar Z-bars in the rite width but the tab position varies. Then the other crucial point is throw-out bearing to finger clearance, should be @ least 0.050". Also be sure to use the proper return spring as speced by Mopar, not some universal type.

Just my $0.03...
Posted By: DGS

Re: Calculate clutch pedal travel - 08/07/14 09:26 PM

Should have mentioned that I'm going to use a hydraulic setup.
Posted By: poorboy

Re: Calculate clutch pedal travel - 08/08/14 05:14 AM

You have to be close to right, I don't think the clutch pedal on my Dakota travels more then 4" from pedal stop on top of the stroke to the floor.

If I remember, I'll try to measure the stroke tomorrow. Gene
Posted By: John_Kunkel

Re: Calculate clutch pedal travel - 08/08/14 07:23 PM


Can't fault your math but 4" of pedal travel with a 6-1 pedal ratio is only gonna move the MC pushrod .666".

I have an almost identical setup and the pedal travel is a little over 6" which moves the pushrod 1" out of 1 3/8" available in the MC. Mine engages closer to the floor than I'd like.
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