best way to know when clutch locks up

Sam Ehret · 10-14-2014, 06:20 PM

I have been running a four speed with a 7.25 diameter,two disk clutch. It has base pressure adjustment and counterweight adjustment. I have an O2 alert data recorder that has a driveshaft sensor mounted on the differantial yoke.
I have been downloading my runs and overlay the rpm and driveshaft readings. The tach goes to 7700 rpm when I drop the clutch, and drops to 5500 before it starts going back up. This is always 1.25 seconds. The driveshaft readings seem to gradually go up with little spin. At what point is the clutch locking up? How do you determine that point? Application is Muncie M20 with 5.38 gears, 3300 lb car. 327 engine.

ss3011 · 10-14-2014, 07:22 PM

Multiply the driveshaft rpm by the transmission gear ratio, when that number matches the engine rpm, the clutch is locked up.

Chris Hill · 10-14-2014, 10:33 PM

Another way is to take engine rpm/driveshaft rpm.

When clutch is locked up, the ratio will be constant vs time in a specific gear.

10-14-2014, 06:20 PM	#1
Sam Ehret Junior Member Join Date: Jul 2014 Posts: 18 Likes: 4 Liked 0 Times in 0 Posts	best way to know when clutch locks up I have been running a four speed with a 7.25 diameter,two disk clutch. It has base pressure adjustment and counterweight adjustment. I have an O2 alert data recorder that has a driveshaft sensor mounted on the differantial yoke. I have been downloading my runs and overlay the rpm and driveshaft readings. The tach goes to 7700 rpm when I drop the clutch, and drops to 5500 before it starts going back up. This is always 1.25 seconds. The driveshaft readings seem to gradually go up with little spin. At what point is the clutch locking up? How do you determine that point? Application is Muncie M20 with 5.38 gears, 3300 lb car. 327 engine.

10-14-2014, 07:22 PM	#2
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: best way to know when clutch locks up Multiply the driveshaft rpm by the transmission gear ratio, when that number matches the engine rpm, the clutch is locked up.

10-14-2014, 10:33 PM	#3
Chris Hill Senior Member Join Date: Jan 2002 Posts: 653 Likes: 8 Liked 238 Times in 25 Posts	Re: best way to know when clutch locks up Another way is to take engine rpm/driveshaft rpm. When clutch is locked up, the ratio will be constant vs time in a specific gear. __________________ Chris Hill https://ihmusedparts.com