Race Car Tech Discuss anything related to road racing and auto X.

Bearings in LSD?

Old 10-15-04, 05:29 PM
  #1  
Losing Traction on 335s
5 Year Member
Thread Starter
 
RX-Ben's Avatar
 
Join Date: May 2004
Location: NYC
Posts: 225
Likes: 0
Received 0 Likes on 0 Posts
Bearings in LSD?

Anyone know if there are any grease packed bearings in an FD Torsen LSD?

Are the carrier bearings grease packed?

Thanks
Ben
RX-Ben is offline  
Old 10-18-04, 12:46 AM
  #2  
Rotary Enthusiast
 
Join Date: Dec 2001
Location: Delaware
Posts: 1,176
Received 0 Likes on 0 Posts
all internals are lubed by the fill gear oil. Only rolling element bearings are the carrier bearings. friction at gear mesh and thrust surfaces define the degree of lock-up .... extra modifiers ( slippery stuff from GM or redline) will reduce lock-up.
KevinK2 is offline  
Old 10-18-04, 09:16 AM
  #3  
Losing Traction on 335s
5 Year Member
Thread Starter
 
RX-Ben's Avatar
 
Join Date: May 2004
Location: NYC
Posts: 225
Likes: 0
Received 0 Likes on 0 Posts
Thanks very much for the reply- I'm getting the LSD cryo treated and was just making sure there wouldn't be any problems due to grease packed bearings.

Thanks
Ben
RX-Ben is offline  
Old 10-24-04, 04:42 PM
  #4  
Former Rx7 *****
10 Year Member
 
Cheers!'s Avatar
 
Join Date: Nov 2001
Location: Mississauga
Posts: 4,532
Likes: 0
Received 0 Likes on 0 Posts
save your money on the cryo treating BS
Cheers! is offline  
Old 10-24-04, 06:29 PM
  #5  
Losing Traction on 335s
5 Year Member
Thread Starter
 
RX-Ben's Avatar
 
Join Date: May 2004
Location: NYC
Posts: 225
Likes: 0
Received 0 Likes on 0 Posts
Care to explain your position?
RX-Ben is offline  
Old 10-24-04, 06:55 PM
  #6  
Former Rx7 *****
10 Year Member
 
Cheers!'s Avatar
 
Join Date: Nov 2001
Location: Mississauga
Posts: 4,532
Likes: 0
Received 0 Likes on 0 Posts
Cryo treating aka freezing metal to temperatures at which nitrogen or helium are liquids do not change the grain structure of the metal. The grain structure is determined by the rate at which the metal cool when brought up to a tempering temperature. For iron alloys you are looking for martinsite grain structure, which is accomplished by rapidly cooling the metal such that it passes through certain regions on the phase diagram. For aluminum it is not largely dependant on the grain structure, it is more dependant on the alloying content and the heat treatment of the aluminum to relieve internal stresses by tempering at temperatures above zero degrees C.

If you look at any phase diagram in any metalurgical text book you will see the phase diagram stops at around room temperature, since nothing happens beyond that point.
Cheers! is offline  
Old 10-24-04, 09:07 PM
  #7  
Rotary Freak
5 Year Member
 
Join Date: Jan 2004
Location: tampa
Posts: 1,899
Likes: 0
Received 0 Likes on 0 Posts
/\ ok. well nascar is spending a ton of money on it now that they have limited engines for qualfying and racing. some places may not do it correctly but race teams do report better life/wear etc...
mad_7tist is offline  
Old 10-25-04, 05:59 PM
  #8  
Losing Traction on 335s
5 Year Member
Thread Starter
 
RX-Ben's Avatar
 
Join Date: May 2004
Location: NYC
Posts: 225
Likes: 0
Received 0 Likes on 0 Posts
more info

RX-Ben is offline  
Old 10-25-04, 06:25 PM
  #9  
Senior Member
5 Year Member
iTrader: (2)
 
Slacker7's Avatar
 
Join Date: Sep 2002
Location: Mississippi
Posts: 287
Likes: 0
Received 0 Likes on 0 Posts
Cryotreatment is done to acchieve the same effect as shot peening which is to create compressive residual streeses on a part to improve fatigue performance and not to change it's grain structure.
Slacker7 is offline  
Old 10-25-04, 07:09 PM
  #10  
Losing Traction on 335s
5 Year Member
Thread Starter
 
RX-Ben's Avatar
 
Join Date: May 2004
Location: NYC
Posts: 225
Likes: 0
Received 0 Likes on 0 Posts
from what I've read- shot peening only affects the surface of the piece (and just under the surface) as opposed to treating the whole piece like cryo does.
RX-Ben is offline  
Old 10-26-04, 05:20 PM
  #11  
Rotary Enthusiast
 
Join Date: Dec 2001
Location: Delaware
Posts: 1,176
Received 0 Likes on 0 Posts
Originally Posted by Slacker7
Cryotreatment is done to acchieve the same effect as shot peening which is to create compressive residual streeses on a part to improve fatigue performance and not to change it's grain structure.
not true.

shot peening is as stated, and mainly to avoid cracking due to fatigue. I've spec'd it many times.

Cryo does change the grain structure, and is mainly for improved wear in heat treated med/high carbon steels (gears, tooling dies). Also works on brake rotors. I have not seen any data to support any fatigue life improvements.

Nitriding carbon steel creats hard, compressive layer in steel that resists wear and fatigue.

A torsen lsd has lots of thrust loads on the planet gears, and may benefit from cryo treatment. It may also change the degree of lock-up.

Last edited by KevinK2; 10-26-04 at 05:24 PM.
KevinK2 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Vartok
2nd Generation Specific (1986-1992)
16
10-08-15 04:49 PM


Thread Tools
Search this Thread
Quick Reply: Bearings in LSD?


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: