Small block chevy main bearing issue (assembly) - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 06-17-2008, 09:55 PM
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Sacramento, CA
Posts: 68
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Small block chevy main bearing issue (assembly)

I am trying to put a small block chevy 350 back together and the rear main bearing seems to be wrong. It does not fit over the crank. The crank is ground .010 under and the bearings match in this respect. The thrust surfaces of the bearing do not fit into the crank. The old bearing and the new bearing have the same part number stamped in the back 32020-cp. The casting number on the crank is 932442. Measuring across the bearings there was about .020 difference between the old bearing and the new bearing, with the new bearing being the larger of the two, which I am sure is the problem. I took back the first set of bearings thinking it was a defect and the new bearings have the same problem. From what I can tell from the numbers I think this is a 1975 motor. Are there different types of bearings for this? The bearing brand I am using is Federal Mogul. If anyone has any suggestions I would love to hear them.

Thank you,

Josh

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-17-2008, 11:02 PM
68NovaSS's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Working with chromed bolts
Last journal entry: New to me T-Bucket
Last photo:
Join Date: Sep 2002
Location: Nine Mile Falls/Suncrest, WA
Posts: 5,258
Wiki Edits: 9

Thanks: 105
Thanked 133 Times in 124 Posts
The rear main is going to be a snug fit, does the upper half seat into the block saddle OK? Are yoiu saying the cap won't go on after the bearing is in it or the bearing half won't insert into the cap?
__________________
Boost adds dignity to what would otherwise be a vulgar brawl...

Midnight Sun Street Rod Association
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-17-2008, 11:14 PM
406 bug's Avatar
9.82 @ 139mph
 
Last wiki edit: Finding vacuum leaks Last photo:
Join Date: Nov 2007
Location: phoenix, arizona
Posts: 582
Wiki Edits: 1

Thanks: 0
Thanked 1 Time in 1 Post
The casting no. indicates a 305 or 350 crank. Both have the same 3.48 stroke and 2.45 main journal. Have you installed all the mains with bearings whitout the crank and measured the difference between the crank journal. Is the crank the same one you removed form the engine??
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-17-2008, 11:17 PM
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Sacramento, CA
Posts: 68
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by 68NovaSS
The rear main is going to be a snug fit, does the upper half seat into the block saddle OK? Are yoiu saying the cap won't go on after the bearing is in it or the bearing half won't insert into the cap?
with the bearing in the block, the crank will not sit in the bearing. The bearing also will not go onto the crank outside of the block because it does not fit in between the thrust surfaces.

Someone else suggested that the bearing is intended to work with a crank where the thrust surfaces have each been machined .010". I like this theory because the numbers check out. So I think I need a bearing that is .010" on the diameter and standard width on the thrust. Anyone know where one could find such a bearing? None of the parts houses have asked for the measurement across the bearing.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-17-2008, 11:19 PM
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Sacramento, CA
Posts: 68
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by 406 bug
The casting no. indicates a 305 or 350 crank. Both have the same 3.48 stroke and 2.45 main journal. Have you installed all the mains with bearings whitout the crank and measured the difference between the crank journal. Is the crank the same one you removed form the engine??

I think I understand the measurement you are after, and do not think I have the tool to measure this. I have a vernier caliper and plastigauge to work with as far as measuring goes. This is the same crank that I took out of this block.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-18-2008, 10:17 AM
boatbob2
 
Join Date: Dec 2005
Location: north florida
Age: 76
Posts: 1,374
Wiki Edits: 0

Thanks: 6
Thanked 24 Times in 21 Posts
bearings...

Hi,i dont have a suggestion,but,why not take the crank and brearings to a good machine shop,and ask them.im sure an automotive machine shop has the answer.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-18-2008, 10:29 AM
Double_v23's Avatar
Horsepower Enthusiast
 

Last journal entry: Finished BMOD001FH
Last photo:
Join Date: Jul 2007
Location: Mooresville, NC
Posts: 1,495
Wiki Edits: 0

Thanks: 0
Thanked 5 Times in 5 Posts
Are you suggesting that the thrust surfaces need to be machined .010 under? Because that is definately not true. There is a chance you just got a bad rear main bearing. stranger things have happened.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-18-2008, 01:28 PM
King of my Man-cave.
 
Last photo:
Join Date: Nov 2003
Location: Michigan
Age: 55
Posts: 2,899
Wiki Edits: 0

Thanks: 3
Thanked 15 Times in 12 Posts
What it the part # of the bearing set you have?

tom
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 06-18-2008, 06:44 PM
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Sacramento, CA
Posts: 68
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by Double_v23
Are you suggesting that the thrust surfaces need to be machined .010 under? Because that is definately not true. There is a chance you just got a bad rear main bearing. stranger things have happened.
I am thinking that the bearings were intended to go with a crank where they have been, but that this one is not. I got another set of bearings that I think are right. I will let you know how it works out.

Josh
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 06-20-2008, 06:14 PM
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Sacramento, CA
Posts: 68
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Everything went together perfectly with the new bearings with a standard thrust surface. Thank you for the help.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 06-20-2008, 06:20 PM
King of my Man-cave.
 
Last photo:
Join Date: Nov 2003
Location: Michigan
Age: 55
Posts: 2,899
Wiki Edits: 0

Thanks: 3
Thanked 15 Times in 12 Posts
Thank you very much for posting your results.

tom
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 06-20-2008, 06:22 PM
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Sacramento, CA
Posts: 68
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by machine shop tom
Thank you very much for posting your results.

tom
No problem, I hate it when a search turns up the same problem with no resolution.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why I have grown to hate the Small Block Chevy..... an essay Centerline Hotrodders' Lounge 316 02-08-2012 10:46 PM
big block or small block chevy 69YENKONOVA Engine 81 05-13-2010 07:26 AM
Big Block vs Small Block Chevy bigjoedo Engine 82 05-03-2010 03:36 PM
Chevy small block fuel injection homesimpsonr Engine 7 05-19-2007 04:11 PM
Chevy Small Block Heads druss32 Engine 17 05-10-2006 08:35 PM


All times are GMT -6. The time now is 08:17 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.