#21  
Old 09-11-2019, 09:05 AM
389 389 is offline
Suspended
 
Join Date: Mar 2018
Location: Pittsburgh
Posts: 561
Default

I always wanted to try a pair of 1970 and up Firebird upper control arms with tall .9 and .5 ball joints with the stock lower control arm..

  #22  
Old 09-11-2019, 10:16 AM
Schurkey Schurkey is offline
Ultimate Warrior
 
Join Date: Aug 2002
Location: The Seasonally Frozen Wastelands
Posts: 5,891
Default

Quote:
Originally Posted by weevilkenevil View Post
I am at this point right now with my 65 gto...
PARAGRAPHS!

  #23  
Old 09-11-2019, 05:18 PM
Old Goat 67's Avatar
Old Goat 67 Old Goat 67 is offline
Ultimate Warrior
 
Join Date: Jan 2004
Location: La., 67 GTO, Original Owner
Posts: 6,720
Default

I can't read it either. So, I don't.

  #24  
Old 09-18-2019, 08:02 PM
LATECH's Avatar
LATECH LATECH is offline
Chief Ponti-yacker
 
Join Date: Mar 2011
Location: Indoors
Posts: 594
Default

Quote:
Originally Posted by george kujanski View Post
So I need my memory refreshed......on an "A" body....

If I want to add positive caster without messing up anything else, removing a shim from the front bolt and adding it to the rear bolt does the trick, right?

Also, any idea what the relationship of the shim thickness and the change in caster is, if the above is true?

George
Actually no. You have it backerds man

Move the Shim from the rear to the front . You want to move the upper ball joint rearward to add caster (+) .
Funny that the whole thread no one caught that

  #25  
Old 09-19-2019, 04:53 AM
Geoff Geoff is offline
Ultimate Warrior
 
Join Date: Jul 2005
Location: Australia
Posts: 2,470
Default

Latech,

No one 'çaught' it because there was nothing to be caught...

George's assumption was correct.

  #26  
Old 09-19-2019, 07:11 PM
LATECH's Avatar
LATECH LATECH is offline
Chief Ponti-yacker
 
Join Date: Mar 2011
Location: Indoors
Posts: 594
Default

Quote:
Originally Posted by Geoff View Post
Latech,

No one 'çaught' it because there was nothing to be caught...

George's assumption was correct.
Duh ,My bad.

I just realized why.The cross shaft being inboard of the mount, not outboard.
It sucks not remembering details like that
Like I havent done an alignment in 100 years
Sometimes I just miss the obvious.
Guess I shoulda raised the hood.

Geez

  #27  
Old 09-20-2019, 04:54 PM
mgarblik mgarblik is offline
Ultimate Warrior
 
Join Date: Mar 2005
Posts: 6,035
Default

Quote:
Originally Posted by Schurkey View Post
MY philosophy with a stock- or near-stock suspension in good condition, is to shoot for negative camber, minimum toe, and all the positive caster I can get while keeping the camber negative.

HOW MUCH negative camber is up for discussion. So far as I'm concerned, the most-negative camber according to OEM spec is the most-positive I'd want.

In other words, if the OEM spec for camber is +2 to -1/4, I would want to be at -1/4 to -1/2, maybe as much as -1 depending on the suspension geometry and intended use. I don't get too worried about tire wear at 1/2 degree, I have some concern at 1 degree or more. If you're driving a grocery-getter, you look for maximum tire life. If you're looking for cornering power, some tire life gets sacrificed.

Remember, the engineers and lawyers DELIBERATELY sabotaged the handling of these cars when they were designed. They would build-in boatloads of understeer in order to absolutely prevent oversteer. Part of that was spring rates, sway-bar and tire sizing, but some of that was adding too damn much positive camber. There's also the issue of dynamic camber change--tall and soft springs coupled to too-short steering knuckles leads to lots of body roll. Lots of body roll leads to positive-going camber change on the outside, load-bearing wheel, only some of which is removed as the outside suspension compresses on the turn.

Camber is a tire-wearing angle. It will also cause "pull". Caster is not a tire wearing angle, but also causes "pull"--but it takes twice the caster to pull as much as camber. Used to be, cars were intentionally aligned to pull slightly left. Roads were "crowned", so the roadway itself made the car drift to the right. Highway engineers are taking the crown out of the roadway in favor of humps and dips. I don't approve, but no-one asked my permission. Given a choice, I like to have a vehicle that will drift VERY SLIGHTLY to the right on typical roadways. Driver falls asleep, he hits the ditch instead of oncoming traffic.

IN GENERAL, a 1/4 degree difference in camber L/R, or a 1/2 degree difference in caster l/R was used for road-crown compensation. I'm not sure that much difference is needed any more as roads have less crown.

The trick is to get the camber where you want it, while maximizing positive caster. Positive caster makes for strong self-centering of the steering, and also increased steering effort--but these cars had way too much steering assist to begin with, so extra effort is a non-issue.

Then a minimal amount of toe especially with wide tires. Too much toe wears tires really fast, and makes for wildly unpredictable handling--twitchy, darty, won't-go-straight. With rear-wheel drive, toe-in partially compensates for worn steering joints and loose wheel bearings. If the suspension/steering is still "tight",--and it better be--you don't need a lot of toe.
X2! This post is almost word for word from the Hunter Engineering alignment basics book from the 1970's. As correct today for our old cars as it was then. Great info and refresher course.

  #28  
Old 09-20-2019, 05:34 PM
Schurkey Schurkey is offline
Ultimate Warrior
 
Join Date: Aug 2002
Location: The Seasonally Frozen Wastelands
Posts: 5,891
Default

Quote:
Originally Posted by mgarblik View Post
X2! This post is almost word for word from the Hunter Engineering alignment basics book from the 1970's. As correct today for our old cars as it was then. Great info and refresher course.
Holy crap, I must be old.

So far as I know, I've never read the Hunter book. But maybe that's what the Vo-Tech used for a textbook...

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 11:12 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017