HOME FORUM RULES CONTACT
     
   
   

Go Back   CLASS RACER FORUM > Class Racer Forums > Stock and Super Stock Tech


Reply
 
Thread Tools Display Modes
Old 04-27-2016, 09:38 AM   #1
Cdncarnut
Member
 
Cdncarnut's Avatar
 
Join Date: Jul 2012
Posts: 200
Likes: 305
Liked 44 Times in 27 Posts
Default 12-Bolt Spool Bearing Pre-Load

I have searched this entire forum and cannot find the answer.

I am doing a ring and pinion swap in a 12-bolt, in my Stocker, and would like to know what everyone is using for the pre-load for the spool bearings.

I realize that the spool should spin as freely as possible, but how many thousands is the minimum pre-load that is acceptable.

Thank you in advance.
__________________
Thomas
NHRA 1959 E/SA
Cdncarnut is offline   Reply With Quote
Old 04-27-2016, 09:51 AM   #2
Dragsinger
VIP Member
 
Join Date: Jul 2008
Location: Liberty City [East Texas]
Posts: 1,759
Likes: 5
Liked 98 Times in 59 Posts
Default Re: 12-Bolt Spool Bearing Pre-Load

Thomas,

my method that has proven to give excellent results;

I select a shim pack that provides the backlash number I want and those shims will GENTLY tap into place with a small hammer. Thus, very light preload. It does require several trial fits to sneak up on the combination.

And speaking of preload, I also use very light preload with the pinion bearings and install a solid spacer that adjust with a shim pack.

When the install is complete as I describe the complete assembly is very easy to turn and the car is very easy to push.
__________________
Larry Woodfin 471W
Dragsinger is offline   Reply With Quote
Old 04-27-2016, 10:08 AM   #3
Danny Ashley
Member
 
Join Date: Nov 2001
Location: Marion,In.
Posts: 254
Likes: 40
Liked 91 Times in 23 Posts
Default Re: 12-Bolt Spool Bearing Pre-Load

Thomas:
I read years ago that the total shim thickness is around .484. I have measured many stock cast iron shims and found this to be pretty accurate. My latest one came in at .488. I'm sure every housing is different but the .484 will get you in the ballpark. I've done so many that you get a feel how hard the last shim drives in and how easy the carrier comes out. Speaking of which, placing a boxed end wrench on a ring gear bolt so it jams against the housing and rotating the pinion clockwise is the easy way to get the carrier moving out enough to get 2 pry bars in the bearings/shims. Hope this helps.
Danny Ashley is offline   Reply With Quote
Old 04-27-2016, 10:09 AM   #4
Ed Wright
Veteran Member
 
Ed Wright's Avatar
 
Join Date: Mar 2005
Location: Sand Springs, OK
Posts: 8,132
Likes: 896
Liked 389 Times in 168 Posts
Default Re: 12-Bolt Spool Bearing Pre-Load

Proper pre load will cause every roller to roll anytime you rotate the spool.
__________________
Ed Wright 4156 SS/JA
Ed Wright is offline   Reply With Quote
Old 04-27-2016, 10:56 AM   #5
Dragsinger
VIP Member
 
Join Date: Jul 2008
Location: Liberty City [East Texas]
Posts: 1,759
Likes: 5
Liked 98 Times in 59 Posts
Default Re: 12-Bolt Spool Bearing Pre-Load

What Ed says is correct, that is my method. All bearings in the assembly have "just enough" preload to made that happen.

In my experience, there is no need for preload beyond just having the slack out.

NOTE: with a situation of very high horsepower the setup could be different but I do not deal in that area. My experience is with stockers, super stockers and street driven cars.

I like the Chevy 12 bolt and think it is a good choice for many builds. Yet, the factory housings are disappearing quickly.
__________________
Larry Woodfin 471W
Dragsinger is offline   Reply With Quote
Old 04-27-2016, 11:36 AM   #6
Ed Wright
Veteran Member
 
Ed Wright's Avatar
 
Join Date: Mar 2005
Location: Sand Springs, OK
Posts: 8,132
Likes: 896
Liked 389 Times in 168 Posts
Default Re: 12-Bolt Spool Bearing Pre-Load

Moser has a very nice 12 bolt. That is what I use, their whole 12 bolt rear end. Order the width you need, bolt circle, etc. Good people to deal with.
__________________
Ed Wright 4156 SS/JA
Ed Wright is offline   Reply With Quote
Old 04-27-2016, 07:06 PM   #7
Lew Silverman
VIP Member
 
Lew Silverman's Avatar
 
Join Date: Mar 2010
Location: Newport News, VA
Posts: 1,441
Likes: 373
Liked 129 Times in 59 Posts
Default Re: 12-Bolt Spool Bearing Pre-Load

I've had good luck with the "Super Shim Pack" kit from Randy's Worldwide (www.ringpinion.com). The shims fit between two halves of a machined spacer, which makes installing them MUCH easier. They also have have the crush-sleeve replacement spacer and shim kit that Larry mentioned as well.

Lew
__________________
Lew Silverman #2070
"The Wagon Master" N/SA
Lew Silverman is offline   Reply With Quote
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 04:57 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © Class Racer.com. All Rights Reserved. Designated trademarks and brands are the property of their respective owners.