Ryan---I've installed three* of the KOYO throwout bearings in the last
two years in two, different TR6's.
The first time I used this bearing I installed it "unloaded". That is,
without the "extra" spring pressure that would keep the bearing always
spinning. As did yours, the whirr came in at about 2,000 miles. When I
complained to TRF, they immediately sent me a new one.
Before removing the first Koyo, I imagined it's rollers were protesting
because they were dry and loose, as found on several RHP bearings. To my
surprise I found neither to be the case. (I confirmed this was not a
bearing noise, by spinning it with a drill press, set to different
pressure levels, for various lengths of time and speeds.)
What I did see was excess wear on the fingers, coming from what I
perceived to be the initial contact between bearing and fingers, as the
bearing tried to get up to clutch speed during gear changes and the
like.
*To shorten this story a little, I faced off the "worn area" on the
fingers, reinstalled the first Koyo again, and this time preloaded it
with a measured 15 lb. of spring pressure. It ran silent for the next
6,000 miles. At that time I had to replace the clutch itself (for other
reasons) and this was when I installed the Gunst, with a different
Borg&Beck. Also preloaded as recommended by Gunst, it has run silent for
about 7,000 miles, now.
The second Koyo is running preloded and happily (?) in another TR6. He
only drives it about 3,000 miles a year, and I haven't seen it since.
TRF doesn't agree with preloading. I have found that a good bearing can
spin a loong time, all the time, without harm. (Consider what the front
wheel bearings go thru)
For sure, there's no whirr from come-up when the two parts are turning
at the same speed. I expect the clutch fingers to look good at the next
inspection.
It takes 35 lb. of force to disengage the B&B clutch, as measured at my
clutch pedal. Feels just about right.
I don't know if Nelson has any Gunst left over, from his original order
of 34.
Dick Taylor
|