[6pack] Gunst Bearing Experiences?

[Sally or Dick Taylor]

By using a "+..005" oversized washer, I set my thrust washer clearance for a total of .003, which is tighter than  "recommended" That was around 60,000 miles ago. The last time I checked this, about 10,000 miles ago, the clearance was indicated at .005. Because of this history, I seriously doubt that the nominal preload as Mr. Gunst recommended will cause any premature failure. Likewise, doubling the preload should have a minimal effect, given the total weight of the crankshaft and the force necessary to move it.
I like your idea of just listening to see if you can hear any sound coming from the clutch-to-bearing interface. As you noted, t's easy enough to add preload.

Nelson and I exchanged quite a bit of info on the dreaded clutch squeal that was taking place about 7-10 years ago. I'm glad he documented this effort! I wish he were still in the Triumph hobby!

Dick


-----Original Message-----
From: Tomislav Marincic
Sent: Sunday, April 5, 2009 6:11 AM
To: Sally or Dick Taylor
Cc: 6pack
Subject: Re: [6pack] Gunst Bearing Experiences?

Dick,

Thanks for the reply. In my investigation of the clutch saga, I keep
running across your name, so I feel very fortunate to have your opinion
available.

It seems like the TOB's that are not seating at 15mm preload are all giving
plenty of audible warning, so I'll start with 15mm/top hole and listen
carefully. I can always increase the preload if I hear the dreaded chirping.

I appreciate your comments about the amount of force required to release
the clutch, but it's not a damaged TOB I'm worried about, but rather an
engine thrust bearing that wears prematurely from the constant force.
Otherwise, I'd set 30mm/bottom hole and be done with it.

Your idea for the drill press is good, but my bearing is already entombed
in the drivetrain.

Thanks to you and everyone who replied.

Cheers, Tom


> [Original Message]
> From: Sally or Dick Taylor <tr6taylor at webtv.net>
> To: <tomislav.marincic at earthlink.net>; 6pack <6pack at autox.team.net>
> Date: 4/5/2009 2:47:33 AM
> Subject: Re: [6pack] Gunst Bearing Experiences?
>
> Tom---The idea behind the preload is to make certain that the Gunst
bearing never stops spinning with a running clutch. A stretch of 15mm
connected to the top hole in the arm should be enough to do the trick. As
the clutch disc lining wears, the spring is stretched further, increasing
the preload, slight as this may be.  If you want to make a simple setup
here, rig up something to see how much tension is necessary to spin the
bearing. You can use a drill press and a bathroom scale. Compare the
poundage necessary to stretch the given spring 15mm. Find a compression
spring that when compressed 15mm, equals the same poundage.
>
> Consider that when the clutch is disengaged it takes about 250 to 300 lb
to do so. (Many, many times the preload).  I don't think you can hurt this
bearing when using the spring provided, even with a 30mm stretch of the
spring, in the bottom hole. Still, I'd go with the original instructions. I
know it works!