hey, no fair including graphics in an e-mail argument!
Actually, very nice work. Next time, please show the function and operation
of carburetor temp compensators and bypass diaphragms, preferably with
animation ...
:)
I believe our difference of opinion comes down to what constitutes "slack."
I agree with you that if the throwout arm does not move under light pressure
(ie a finger's touch), then shimming the cylinder makes no difference.
But if there's enough "slop" in the system (i.e worn clevis pin hole) that
by shimming the position of the master cylinder, you would eliminate the
slop and make everything snug, then I think you'd see some benefit.
Another example: for the carburetors, there is (deliberately) some slack
between the throttle rod and the carburetor linkage. The first tiny bit of
pressure on the accelerator takes up the slop, and continued pushing starts
to rotate the throttle shafts. You can adjust the linkage to increase or
reduce the slack -- which doesn't affect how much the throttle shafts
themselves open or close.
--Graham
-----Original Message-----
From: James Franks [mailto:jimmble@adelphia.net]
Sent: Wednesday, August 21, 2002 1:37 PM
To: Vink, Graham
Cc: Six pack
Subject: Re: Clutch Problem Discussion
"Shimming the cylinder so it is physically located farther toward the
rear of
the car puts that location at Point A plus 1/8 inch (or whatever the
amount
of "slack" is that you have eliminated)."
No....... shimming the cylinder just locates the rod further into the
cylinder by 1/8th inch in your example.
The rod is fixed to the throwout arm and it's position doesn't change.
You just push 1/8th inch of displaced brake fluid up out of your full
reservoir.
This takes a bit to get your mind around the first time. I drew a very
crude bitmap representation of what I'm trying to say . I don't know if
it'll come thru as an attachment to the list, but I can send it to
anyone that cares. :^)
Jim
----- Original Message -----
From: "Vink, Graham" <vinkg@fleishman.com>
To: "Six pack" <6pack@autox.team.net>
Sent: Wednesday, August 21, 2002 12:27 PM
Subject: RE: Clutch Problem Discussion
> Well, I like a good obscure technical discussion as well as the next
guy,
> especially if it threatens to erupt into a flame war and doesn't
involve
> fuel injection, so I'm jumping in with my two bits:
>
> IMHO (and contrary to some other posts by my esteemed fellow listers)
I
> believe it WOULD help slightly if you shimmed out the physical
location of
> the slave cylinder to remove any "slack" in the system (ie worn clevis
pin
> holes).
>
> If we agree that the spring always pulls back the piston of the slave
> cylinder to the same point in the cylinder, regardless of the
cylinder's
> location, then that becomes Point A.
>
> Shimming the cylinder so it is physically located farther toward the
rear of
> the car puts that location at Point A plus 1/8 inch (or whatever the
amount
> of "slack" is that you have eliminated).
>
> When you step on the clutch, you are no longer using the first 1/8
inch of
> piston travel to take up the "slack." So your full 1/2 inch of piston
> movement is being applied directly to the fork, throwout bearing, etc.
>
> This also could compensate modestly for any slack inside the clutch
case if
> it exists (for example, any space between the throwout bearing and the
> fingers on the clutch disc)
>
> I agree that such shimming does not affect the total travel range of
the
> piston. And I also agree the best solution is new parts.
>
> Graham
>
>
> -----Original Message-----
> From: James Franks [mailto:jimmble@adelphia.net]
> Sent: Wednesday, August 21, 2002 11:38 AM
> To: jay_welch@juno.com
> Cc: Six pack
> Subject: Re: Clutch Problem Discussion
>
>
> Jay,
>
> All you can do for a worn clevis and pin is repair and/or replace the
> worn parts. Shimming won't work, and neither will a spring. (All that
> will happen is the slack will be taken up at the beginning of the
> stroke, and the spring will drag the arm back the same distance on
the
> return. Net gain= 0. )
>
> Jim
> ----- Original Message -----
> From: <jay_welch@juno.com>
> To: <6pack@autox.team.net>
> Sent: Wednesday, August 21, 2002 9:16 AM
> Subject: Re: Clutch Problem Discussion
>
>
> > Hello All,
> >
> > My thoughts are that the addition of a 1/4" to 3/8" shim where the
> slave
> > attaches to the plate might make up for worn clevis pins/holes
between
> > the clutch pedal and the rod??? Would I be correct in that
> assumption??
> >
> > Jay Welch, Abington MA
> > Secretary, "Cape Cod British Car Club"
> > http://clubs.hemmings.com/capecodbritish/
> > 1973 TR6 driver, 1971 TR6 project
> > 1989 Mustang GT someday morphing into a Factory Five '65 Roadster
> >
> >
> > On Wed, 21 Aug 2002 05:42:38 -0700 (PDT) michael lunsford
> > <mblunsfordsr@yahoo.com> writes:
> > > Jim Franks wrote:
> > >
> > > <Date: Tue, 20 Aug 2002 09:49:19 -0400
> > > From: "James Franks" <jimmble@adelphia.net>
> > > Subject: Re: Clutch Problem
> > >
> > > <Mike,
> > >
> > > <Moving the slave cylinder, or adding washers, or lengthening the
> > > pushrod
> > > does NOT change the travel range of the slave cylinder piston. It
> > > may
> > > move the travel to an unworn area in the slave cylinder bore,
which
> > > is
> > > the only potential benefit of doing this. ( I have gained a few
> > > years
> > > service from a bad slave this way) With new or unworn parts,
> > > assemble
> > > as
> > > designed for best result>
> > >
> > > My response to the above is that I know that the range of the
slave
> > > cylinder does not change with these alterations. The suggested
> > > changes result in the slave cylinder being in a position that
takes
> > > up any slackness between the pushrod and the initial disengagement
> > > of the throw out bearing fork to the clutch. This idea is
identical
> > > to the fact that the adjustment of the rear brake shoes to the
point
> > > where they are closer to the drums results in less travel in the
> > > brake pedal. This may not be the actual problem but it is a lot
> > > easier to check/try this idea than to remove the transmission to
> > > check the fork/throw out bearing/clutch. I learned this lesson
the
> > > hard way by putting the slave on the wrong side of the plate
during
> > > my restoration-BTDT. Good Luck.
> > >
> > > Mike Lunsford, 1970 TR6
> > > HotJobs, a Yahoo! service - Search Thousands of New Jobs
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