Quote:
Originally Posted by pantdino
What is the advantage of that? Instead of spinning like 1/10,000 of the time it's spinning 100%. I guess they figure if its not under load it won't make any difference? But spinning still creates heat and uses up the grease in the bearing.
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Well, now, @
pantdino , that's an interesting question and one that I had.
Some ol boy somewhere on the interweb explained it this way:
"On "older" cars (prior to about 1980) the clutch system used "free play", i.e. there was a small gap between the throw out bearing and the pressure plate fingers, when the pedal was up (clutch engaged). Throw out bearings were not designed to run a lot, and these bearings could not compensate for mis- alignment.
Starting in the early '80's most clutch systems switched to "self centering" throw out bearings. At the same time, the clutch systems changed from "free play" systems to "constant running" (in other words, the throw out bearing was in constant contact with the pressure plate fingers, and always turning) systems. And they also incorporated self adjusting systems in the release linkage or pressure plate itself."
Now my (humfrz) take on the situation is that, most, back in the day clutches, were dis-engaged with mechanical linkage. So, the TOB was set close to, but not touching, the fingers of the pressure plate. So, when the clutch pedal was pushed down, the fork pushed the cold, non spinning, TOB, against a bunch of steel fingers that were rotating at the speed of the engine.
Talk about a "cold start" and a sudden temperature change......
Now with the hydrolytic clutches, the inner workings of the slave cylinder puts a 5-15 lb/sq/in pressure on the TOB which keeps it in constant contact with the rotating pressure plate fingers. So, it stays warm by spinning all the time the engine is running. When the clutch pedal is depressed it is called upon to "work" by pushing the pressure plate fingers, thus releasing the pressure on the clutch disk.
So, which would the bearing rather do ...... spin all the time and work when called upon ........ or sit there cold and get slammed up against steel fingers spinning at several thousand RPMs .... every now and then....... ??
If I don't have this completely straight, I'm sure ol @
Ultramaroon and maybe others, will chime to correct me ......
humfrz