[TR] TR4 vs TR4A clutch items

[Randall]

> If you do have a TR4A clutch pressure plate installed I would stick
> with the
> TR4A hydraulics to benefit from the faster clutching capability..

FWIW, I have a TR4A style (same as TR6) pressure plate installed on my TR3
with stock hydraulics, and I have no complaints about how fast the clutch
is.  It seems odd to me that they would be allowing for faster (meaning
harsher) clutch operation just when they introduced IRS that was less able
to handle the shock loading caused by rapid clutch engagement (and actually
had to modify the OD for slower engagement).  My opinion is that the later
clutch design had more to do with lower cost than faster operation, but
that's just my $.02 worth.  I'm using it because my Fidanza flywheel was
only drilled for the later pattern.

I do still need to install the little bracket that I made up, to increase
the return spring tension and compensate for the thicker TR6 gearbox flange,
but that's a separate issue.

Also worth noting, perhaps; I believe the TR4A was also the introduction of
the 'self-adjusting' clutch linkage.  The clutch slave return spring was
deleted and replaced by a spring inside the slave cylinder that lightly
holds the throw-out bearing against the pressure plate all the time.  The 4A
still had the adjustable pushrod (I believe) but the need for periodic
adjustment was gone.  Later (during TR5 perhaps), the pushrod adjustment was
also deleted.

-- Randall