[DeTomaso] Upgrade List

[Stephen Nelson]

Great response JDeRyke.  And yes, my comment was poorly written - the
problem is the stub axles.

 

Actually, yes, I joined POCA a while ago, had a lovely chat with Judy, a
very charming lady, and then started following this e-mail group, reading
for-sale ads, and looking at cars that I can find locally.  Hence my
decision to start putting together a list, as I have in fact started doing.
And now I will start reading back issues of the POCA newsletters - hadn't
spotted that option on the site till you mentioned it.

 

In truth, being new to this group, I can assure you I will miss state things
again, yet my desire to learn is first and foremost - and responses like
yours, even ones starting out with "Absolutely wrong" are part of the
process.    

 

Stephen Nelson

 

SNClocks.com <http://www.snclocks.com/> 

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<http://www.snclocks.com/TheRestofourWorld/Hammered-Dulcimers/About-Steves-D
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Click here for my new blog <http://www.perfectoldman.com/>  on finding
happiness in retirement 

 

  _____  

From: JDeRyke at aol.com [mailto:JDeRyke at aol.com] 
Sent: Sunday, September 16, 2012 1:53 PM
To: steve at snclocks.com; detomaso at realbig.com
Subject: Re: [DeTomaso] Upgrade List

 

In a message dated 9/15/12 5:46:27 PM, steve at snclocks.com writes:




But, in searching I read "One of the very week points of the Pantera is the
rear axle bearings. Ball bearings are use to support the axle and are not
very well suited to carry the loads that our big fat sticky tires can exert
on them. A ball bearing is just not a good bearing for handling heavy side
loads. On the Pantera, the single outside bearing carries most of the side
load forces. Roller bearings are a much better solution for handling side
loads and the big fat sticky tires."



Absolutely wrong. What IS critical is the press fit of the outboard stub
axles into the ball bearings; the OEM factory fit was too light or
non-existant in many cases and was due to undersized AXLES made of low-grade
mild steel, not to a weakness in the bearing type. Replacement factory axles
available today have the proper 0.0007" interference fit and are made of
4130 or 300-M alloy steel- both far stronger than original stock axles. They
are suitable for any imaginable use of a Pantera including Pro-racing. 
Ball bearings run cooler and with less power absorption than roller
bearings, which is why ball bearings are used in most racing cars starting
with F-1 and Indy cars and work down from there. The LeMans Gr-4/GT-4
Panteras also ran ball bearings and today, perhaps 90% of the Panteras on
the road run ball bearings including the big-block conversions with
monstrous power and torque & super-sized rear tires. Roller bearings are
made to carry heavy side loads found mostly in the front end, not the back.
The single advantage of tapered roller bearings is, they will tolerate a
sloppy fitting axle. A good press fit is unnecessary, so its easier to tear
down the upright. 
To verify this a couple of decades ago, I converted ONE of my '72s rear
uprights to roller bearings in my shop since there were no commercial
conversions that met engineering standards. I left the other upright with
stock ball bearings, with a proper press fit on the axles. Today after some
50,000 more miles including many high speed runs, open track events,
autocrossing etc, they are both still back there in good shape- no
difference that I can detect except the tapered-roller side cost much more
for parts and machining. I run 12" wide 295-50 x15"s on optional 10" Campy
wheels. 
Boittom line: check your stub axles for looseness via the 'hip-test' and if
any is detected, you likely need new AXLES, not a change of bearing type.

IMHO, It really depends on what you expect from your car. What you need to
do for 21st century upgrades in a Pantera has been covered in many, many
articles published in the POCA Newsletter and in the currently-dormant PI
magazine over the last 20 years. The list runs to over 300 illustrated,
multipage articles that have been vetted by engineers as true improvements.
They cover handing, brakes, tires and wheels, aerodynamics, interior and a
host of other topics. I suggest you join POCA; e-mail Judy McCartney
<JPOCA2 at hotmail.com> for more  info. Good luck- J Deryke, POCA Tech Editor