[DeTomaso] Techno Question: Adjustable Throw Out Bearing Experience

Mon Sep 23 20:18:13 EDT 2019

Dear Guys,

            Thanks for sharing your experience and opinions.  I was curious whether the McLeod Adjustable throw out bearing was superior to the conventional TOB.

            It appears that most of the time, it isn’t necessary.  It appears that in a few cases it is a good option to have.

             For the near and intermediate future, I will continue with the tried and true BCA 1625 throw out bearing.

                            Warmest regards,  Chuck Engles

From: B Hower [mailto:b.hower3400 at yahoo.com] 
Sent: Monday, September 23, 2019 4:47 PM
To: Charles Engles; Mike Drew
Cc: P - Mail List
Subject: Re: [DeTomaso] Techno Question: Adjustable Throw Out Bearing Experience

I uses one of these from PPC because my Pro Comp fly wheel is a ~1/4" thinner than OEM flywheel. With stock throw out set up the throw out hub travels off end of ZF snout and hangs up ... no return ...

Bud #3400 ( Drive it like there is no tomorrow -- for there may not be ! )

On Monday, September 23, 2019, 11:19:24 AM CDT, Mike Drew via DeTomaso <detomaso at server.detomasolist.com> wrote: 

Chuck,

There is a specific reason to use this in lieu of the stock setup. 

If you use a clutch whose finger height is different from the stock Pantera clutch, particularly if it’s shorter, the clutch fork will be too far away for optimal actuation movement. When viewed from the right side, let’s suppose that your short clutch with stock bearing has the clutch fork already at a 135-degree angle, pointing at 430 o’clock when it first touches the stock (short) throwout bearing. As it continues to rotate towards 90 degrees/3 o’clock, it has progressively less forward movement in relation to the linear displacement of the slave cylinder piston, and that reduces clutch motion. 

The adjustable throwout allows you to correct for this fundamental geometry error, by basically lengthening the bearing so that at rest, the fork is perhaps at 210 degrees/7 o’clock.  Depressing the pedal extends the slave piston and the fork rotates towards 160 degrees/5 o’clock. That maximizes the forward linear travel of the throwout bearing for a given amount of clutch fork rotation. 

Your job is to decide if you need this extra help or not. If your clutch has stock finger height, the stock setup should work fine. 

FWIW Lori’s Pantera has a McLeod diaphragm clutch from Pantera Performance Center. It uses the stock throwout bearing and works fine. However they used to advocate use of the adjustable bearing with this setup, something I didn’t learn until after it was installed and working great. Perhaps we just got lucky. 

Put your old stock clutch and new clutch face down on a flat surface and compare finger heights. If the new one is substantially shorter, an adjustable bearing is the way to go.  Presuming your old clutch is ‘correct’, by measuring the total thickness of the old bearing, and the difference in finger height between the old and new clutch, you can determine the thickness of spacers you need to add to the adjustable bearing to get you back in the ballpark.

Cheers!

Mike

Sent from my iPad

> On Sep 23, 2019, at 09:02, Charles Engles <cengles at cox.net> wrote:
> 
>  Dear Forum,
> 
> 
>                    Has anyone used the McLeod Adjustable Throw Out
>  Bearing?  Is it a direct replacement for the BCA 1625?  What are its
>  advantages over the ordinary common BCA1625?
> 
> 
>                                        Curious,  Chuck Engles
> 
> _______________________________________________
> 
> 
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-------------- next part --------------
   Dear Guys,

               Thanks for sharing your experience and opinions.  I was
   curious whether the McLeod Adjustable throw out bearing was superior to
   the conventional TOB.

               It appears that most of the time, it isn't necessary.  It
   appears that in a few cases it is a good option to have.

                For the near and intermediate future, I will continue with
   the tried and true BCA 1625 throw out bearing.

                               Warmest regards,  Chuck Engles

   From: B Hower [mailto:b.hower3400 at yahoo.com]
   Sent: Monday, September 23, 2019 4:47 PM
   To: Charles Engles; Mike Drew
   Cc: P - Mail List
   Subject: Re: [DeTomaso] Techno Question: Adjustable Throw Out Bearing
   Experience

   I uses one of these from PPC because my Pro Comp fly wheel is a ~1/4"
   thinner than OEM flywheel. With stock throw out set up the throw out
   hub travels off end of ZF snout and hangs up ... no return ...

   Bud #3400 ( Drive it like there is no tomorrow -- for there may not be
   ! )

   On Monday, September 23, 2019, 11:19:24 AM CDT, Mike Drew via DeTomaso
   <detomaso at server.detomasolist.com> wrote:

   Chuck,
   There is a specific reason to use this in lieu of the stock setup.
   If you use a clutch whose finger height is different from the stock
   Pantera clutch, particularly if it's shorter, the clutch fork will be
   too far away for optimal actuation movement. When viewed from the right
   side, let's suppose that your short clutch with stock bearing has the
   clutch fork already at a 135-degree angle, pointing at 430 o'clock when
   it first touches the stock (short) throwout bearing. As it continues to
   rotate towards 90 degrees/3 o'clock, it has progressively less forward
   movement in relation to the linear displacement of the slave cylinder
   piston, and that reduces clutch motion.
   The adjustable throwout allows you to correct for this fundamental
   geometry error, by basically lengthening the bearing so that at rest,
   the fork is perhaps at 210 degrees/7 o'clock.  Depressing the pedal
   extends the slave piston and the fork rotates towards 160 degrees/5
   o'clock. That maximizes the forward linear travel of the throwout
   bearing for a given amount of clutch fork rotation.
   Your job is to decide if you need this extra help or not. If your
   clutch has stock finger height, the stock setup should work fine.
   FWIW Lori's Pantera has a McLeod diaphragm clutch from Pantera
   Performance Center. It uses the stock throwout bearing and works fine.
   However they used to advocate use of the adjustable bearing with this
   setup, something I didn't learn until after it was installed and
   working great. Perhaps we just got lucky.
   Put your old stock clutch and new clutch face down on a flat surface
   and compare finger heights. If the new one is substantially shorter, an
   adjustable bearing is the way to go.  Presuming your old clutch is
   `correct', by measuring the total thickness of the old bearing, and the
   difference in finger height between the old and new clutch, you can
   determine the thickness of spacers you need to add to the adjustable
   bearing to get you back in the ballpark.
   Cheers!
   Mike
   Sent from my iPad
   > On Sep 23, 2019, at 09:02, Charles Engles <[1]cengles at cox.net> wrote:
   >
   >  Dear Forum,
   >
   >
   >                    Has anyone used the McLeod Adjustable Throw Out
   >  Bearing?  Is it a direct replacement for the BCA 1625?  What are its
   >  advantages over the ordinary common BCA1625?
   >
   >
   >                                        Curious,  Chuck Engles
   >
   > _______________________________________________
   >
   >
   > Detomaso Email List is not managed by POCA
   > Posted emails must not exceed 1.5 Megabytes
   > DeTomaso mailing list
   > [2]DeTomaso at server.detomasolist.com
   > [3]http://server.detomasolist.com/mailman/listinfo/detomaso
   >
   > To manage your subscription (change email address, unsubscribe, etc.)
   use the links above.
   >
   > Members who post to this list grant license to the list to forward
   any message posted here to all past, current, or future members of the
   list. They also grant the list owner permission to maintain an archive
   or approve the archiving of list messages.

   _______________________________________________
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   list. They also grant the list owner permission to maintain an archive
   or approve the archiving of list messages.

References

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