[6pack] Clutch Master Cylinder diameters

[Navarrette, Vance]

 	rml:

	Add to the clutch MC machinations the fact that there have been
numerous substitutions and cross references for the pressure plate on
the TR6. The early TR6 clutch used the Borg and Beck pressure plate
"yellow spot" design, later TR used the Laycock design (no longer
available except rebuilt) which is alleged to have been very light
indeed. Years later, B&B dropped the yellow spot and started
recommending the stiffer "blue spot" which was from a Ford Van, but some
people mistakenly started using the "green spot" clutch which even
stiffer than the blue spot.
	Add to this the fact that people use Sachs pressure plates (I
have no idea where those fit in the spectrum of pressure plates) and you
have a very convoluted issue.
	I was lucky, I found a NOS yellow spot B&B setup, which combined
with the 0.70" MC on my car yields a very light clutch that engages
halfway off the floor. Perfect. My LBC mechanic commented that it was
the lightest TR6 clutch he had ever driven.
	And of course, the stiffer the pressure plate, the more wear on
the thrust washers every time you depress the clutch pedal. So many
issues stem from the choice of pressure plate and clutch MC.

	Cheers,

	Vance


    Vance Navarrette
    Cogito Ergo Zoom
    I think, therefore I go fast

-----Original Message-----
From: 6pack-bounces+vance.navarrette=intel.com at autox.team.net
[mailto:6pack-bounces+vance.navarrette=intel.com at autox.team.net] On
Behalf Of Robert Lang
Sent: Monday, May 12, 2008 7:06 AM
To: im sloane
Cc: 6pack at autox.team.net
Subject: Re: [6pack] Clutch Master Cylinder diameters

Hi,

The early TR6's had a .75 bore clutch MC. They were "heavy", meaning you

need more leg power to push and hold the clutch. At some point (I can't
recall when, but I'll guess at CC50000) the factory switched to a .70
bore
clutch MC. This setup feels "lighter" meaning not as much leg pressure
is
required to push the pedal down.

<snip>

But back to the point - if you're looking for period correctness, you go

with scarce as hen's teeth clutch MC or you go to alternate supply
houses
to get a "deal" on a .75 MC or you do what 99% of the DPO's out there
have
done and switch to th e.70 clutch MC.

c ya,
rml