[DeTomaso] Transmission viewing hole cover

Sun Jun 10 22:56:03 EDT 2012

Chris...

I have a friend that accuses me of stirring the pot every so often? (who me?) OK...Maybe on a slow day? This little viewing hole cover thing was kinda interesting!

Thanks
Curt

--- On Sun, 6/10/12, Charles Engles <cengles at cox.net> wrote:

From: Charles Engles <cengles at cox.net>
Subject: Re: [DeTomaso] Transmission viewing hole cover
To: "'Christopher Kimball'" <chrisvkimball at msn.com>, "'Jeff Cobb'" <jeffcobb1 at me.com>, MikeLDrew at aol.com
Cc: guson at home.se, detomaso at realbig.com
Date: Sunday, June 10, 2012, 6:38 PM

Dear Chris,

                    Some people are bomb disposal experts and some people are experts at setting off bombs.   You scored very highly with this topic!   Well done.

                                    Warmest regards, Chuck Engles

From: Christopher Kimball [mailto:chrisvkimball at msn.com] 
Sent: Sunday, June 10, 2012 6:27 PM
To: Charles Engles; 'Jeff Cobb'; MikeLDrew at aol.com
Cc: guson at home.se; detomaso at realbig.com
Subject: RE: [DeTomaso] Transmission viewing hole cover

Sometimes I ask a question just to watch the forum explode...!

Chris

Sent from my Windows Phone

  _____  

From: Charles Engles
Sent: 6/10/2012 3:24 PM
To: 'Jeff Cobb'; MikeLDrew at aol.com
Cc: guson at home.se; detomaso at realbig.com
Subject: Re: [DeTomaso] Transmission viewing hole cover

Dear Jeff,

                Thanks for you insight and review of this arcane issue!   I
will move up the perforated bellhousing cover project on the priority list!
Who knew that this trivial point would end up with a review of clutches and
transmission cooling as well as references to the Mulsanne straight and GT
40 bellhousings!   This Forum is impressive.

                       Warmest regards,  Chuck Engles

From: Jeff Cobb [mailto:jeffcobb1 at me.com] 
Sent: Sunday, June 10, 2012 2:24 PM
To: MikeLDrew at aol.com
Cc: Jeff Cobb; sdlgibson at sbcglobal.net; guson at home.se; detomaso at realbig.com;
cengles at cox.net
Subject: Re: [DeTomaso] Transmission viewing hole cover

How many other cars do you know of that have such a venting scheme on their 
bellhousings?   I can't think of a single one....

Mike

Hello group,

Interesting clutch temp thread.

For the last 120 years or so a driver would talk about his clutch problems
on a few primary levels:

It slips, it overheats and it chatters. With slip and chattering creating
heat. The clutch only makes rotation shaft motion or heat.

So nearly all clutch problems create unwanted heat which then creates more
slippage. Heat causes surfaces gassing of the fabric matrix which inhibits
correct friction.

The flywheel and pressure plate do try to provide the thermal absorption
required for friction operation of the clutch. 

Heat is the enemy that damages the friction surface and puts undo stress
onto oil seals only inches away.

Not many cars are on the streets today have the high horsepower and mid
engine transmission like the Pantera.

Only a handful of cars have the torque and hp like the Pantera so the clutch
temp comparisons are difficult. 

A new Lambo and Ferrari owner would be so happy if they could get 34,000
miles out of their clutch, which is caused by software that slips the clutch
too much, again a heat issue. 

Also considering that clutch friction weave surfaces have developed so
greatly since the early 70's that the temp problem has lessened immensely. 

I am at work today and went over and checked out some cars in my shop. The
06 and later BMW M5, Viper, Lambo Espada and Murci, Ghibli, Bora, Mustang
Cobra stick shifts have vents. Automatics have the same problems so the Ford
C6 has upper vent slits,  Benz-Jag-BMW ZF's have vents covered with plastic
screens and these mentioned trans have stood the test of time since the
early 70's. Chevys do not and have always has trans damage due to temp.

I have torque convertors in my shop out of 50 and 60's Mercedes today that I
just looked at that have 30 mm or so tall cooling fins built into them for a
turbine cooling flow function. These are all low powered cars. An overheated
{ballooned} convertor will most likely burn/wear out the thrust bearings
faster than a clutch car. It would seem reasonable that a high performance
clutch should have an air flow pump mounted or duct so positive air pressure
would enter the clutch housing and help out. Hell, you could use an exhaust
generated venturi suction tube to remove unwanted heat and dust as the drag
cars due to venting the crankcase.

The clutch like the brake needs cooling air for proper operation even if
your speeds are not,

Cooling might be important at 200 mph on the Mulsanne....
Mike. 

Hope this has helped.

Jeff Cobb

Jeff Cobb Auto Works
1316 South Acadian Thruway
Baton Rouge
Louisiana, 70806
www.liveoakconcours.org <http://www.liveoakconcours.org/> 
Concours, April 12-14, 2013
Work  225-343-7525
Fax     225-343-7550
zumzum at cox.net
jeffcobb1 at me.com                                     

On Jun 10, 2012, at 12:26 PM, MikeLDrew at aol.com wrote:

In a message dated 6/10/12 7 16 31, sdlgibson at sbcglobal.net writes:

Is it possible that the spinning clutch assembly act as an "impeller" so 

to speak and draws in cooler air to aid in cooling?  Some of the older 

units have 2 ports and maybe this acts as an intake and exhaust.  Just some 

food for thought. 

The holes are to vent heat out, not draw cool air in....

How many other cars do you know of that have such a venting scheme on their 
bellhousings?   I can't think of a single one....

Mike
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