<VV> Update on pressure plate compression issue

[Steve Brennan]

In order to address my excessive pressure plate finger compression, it was
suggested that I put washers between the pressure plate and the flywheel.
So I put .10" thick washers under the six legs and reinstalled the assembly.
Now, the fingers move approximately 11/32", nicely within Larry Claypool's
recommended range.  So now my question is, given that the early pressure
plate already has small hexagon-shaped "feet" (washers welded on flywheel
side of the legs), should I use slightly longer bolts to attach the pressure
plate?  The number of turns before the bolts bottomed out was noticeably
less with the washers installed, so it has me wondering if there is enough
thread contact.

 

Also, does the fact that this suggestion worked indicate that my pressure
plate is defective?  Should I delay reassembly and see if I can try another
pressure plate?

 

Thanks,

Steve Brennan

1962 Spyder Coupe 

 

From: Steve Brennan [mailto:Alohaz at ca.rr.com] 
Sent: Saturday, February 16, 2008 2:03 PM
To: 'virtualvairs at corvair.org'
Subject: RE: How much should pressure plate fingers compress? 

 

This is a follow-up to my previous post.  I found similar instructions
regarding measuring the finger compression in Corvair Basics, and apparently
there is no distinction between the two pressure plates.

I have checked everything again and my measurements were accurate (approx.
7/8" finger compression).  Also, I have confirmed that I have an early
flywheel (not recessed), and a flat fingered pressure plate.  There is just
a lot of pressure plate compression that occurs as the bolts are tightened,
which results in the fingers ending up relatively close to the clutch disk
hub.  It makes sense to me that, given such a situation, I would have
problems getting the disk to fully release, which is consistent with the
symptoms I have been experiencing.

At this point, I don't know what to do.  If nothing else I will call Lon at
CU as soon as they are open and ask if the pressure plate could be too thick
or something.  (Is it possible to tell anything by getting the "standard"
measurements of the distance between the pressure plate ring and the "legs"
that bolt to the flywheel, so I can compare those to mine.)  I am at a loss.


Thanks for any suggestions or thoughts.
Steve

 

From: Steve Brennan [mailto:Alohaz at ca.rr.com] 
Sent: Saturday, February 16, 2008 11:38 AM
To: 'virtualvairs at corvair.org'
Subject: How much should pressure plate fingers compress?

 

In response to my earlier clutch/throw out bearing posting, Doug Mackintosh
was kind enough to send me the following tip he had previously received from
Larry Claypool:

 "as mentioned in my article in the tech guide, you should always check how
much the fingers of the pressure plate move when you tighten the bolts. if
the fingers move more than 1/2 " at the center, you can be assured you will
have problems getting it to release; less than 1/4'' and it will begin to
slip after a little wear. assuming the step in the flywheel is at the
correct depth, the difference is almost always in how the pressure was built
up. the thickness of the disc also comes into play, but much less so than
the p/plate."

So, as the first step in the reassembly process, I measured the movement of
the p/plate fingers before and after tightening, and was shocked to find
they move (compress) approximately 7/8".  Does this mean I have a problem
with one or more of the relevant parts, or were Larry's numbers for the bent
finger p/plate?  I was planning on putting the car back together and test
driving it today, but now I'm not sure what to do.

Thanks in advance,
Steve

1962 Spyder Coupe