Ask Experts Questions for FREE Help !
Ask
    7up's Avatar
    7up Posts: 180, Reputation: 1
    Junior Member
    		  
    #1

    Jan 18, 2009, 06:53 AM
    Main and rod bearing clearances spec
    On a 350 small block chevy eng,could anyone tell me what the spec should be for main and rod bearing oil clearance,and would standard bearings have the correct oil clearance for both if no work has been done to the crankshaft.all answers will be helpful


    Thanks to all
    CaptainRich's Avatar
    CaptainRich Posts: 4,492, Reputation: 537
    Cars & Trucks Expert
    		  
    #2

    Jan 19, 2009, 03:16 PM

    Standard clearance is, has been, and should always be: .030"
    You should check this with Plasti-gage to make certain.
    curtis73's Avatar
    curtis73 Posts: 5, Reputation: 4
    New Member
    		  
    #3

    Feb 24, 2009, 09:16 AM
    Uh... how about adding another zero there Rich :)

    Typical generic SBC tolerances should range between .001 and .002", but tolerances on the end bearings can vary. Often times the #1 main can be as little as .0008". . 003 is a little loose for my taste, but it can be fine with thicker oil.
    curtis73's Avatar
    curtis73 Posts: 5, Reputation: 4
    New Member
    		  
    #4

    Feb 24, 2009, 09:27 AM
    Quote Originally Posted by 7up View Post
    and would standard bearings have the correct oil clearance for both if no work has been done to the crankshaft.all answers will be helpful
    In a word, no. A used crank will have egg-shaped journals. Simply putting new bearings on a used crank is like putting new linoleum on an old lumpy floor. Putting new bearings on an old crank can be fine, but while its out, why not spend a hundred bucks and have it remanufactured? A machine shop will recut the journals and repolish them.

    The bad side is, often times putting new bearings on old journals will cause a spun bearing which damages the block and is big money to fix... or sometimes can't be fixed.
    curtis73's Avatar
    curtis73 Posts: 5, Reputation: 4
    New Member
    		  
    #5

    Feb 24, 2009, 09:42 AM

    Sorry about the big disagree flag, Captain Rich. I'm new and I'm still learning how to rate things. Is there a way I can remove it?
    CaptainRich's Avatar
    CaptainRich Posts: 4,492, Reputation: 537
    Cars & Trucks Expert
    		  
    #6

    Feb 24, 2009, 09:42 AM
    Quote Originally Posted by CaptainRich View Post
    Standard clearance is, has been, and should always be: .030"
    You should check this with Plasti-gage to make certain.
    I stand corrected.
    My clearance should have been stated as .003"
    And clearances should always be checked in order to select the proper sized bearings.
    CaptainRich's Avatar
    CaptainRich Posts: 4,492, Reputation: 537
    Cars & Trucks Expert
    		  
    #7

    Feb 24, 2009, 09:45 AM
    Quote Originally Posted by curtis73 View Post
    Sorry about the big disagree flag, Captain Rich. I'm new and I'm still learning how to rate things. Is there a way I can remove it?
    You can't remove it.
    My post was inaccurate.
    Being new has nothing to do with it.
    Welcome aboard!
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

FBI fingerprint clearances [ 1 Answers ]

Are paper fingerprints still done in New Jersey for the purpose of FBI clearances and what are the fees?

Chevy s-10 main bearing [ 1 Answers ]

What would cause the main bearing in a 2001 chevy s-10 with 87,000 miles to go out.

Woodstove to wall clearances [ 1 Answers ]

I am planning to install a wood stove in the living room. Can the clearances from the stove to the wall be SAFELY reduced if I install cement board on the walls before having stone placed on the walls and hearth area?

Tiolet Clearances [ 1 Answers ]

I am putting a 1/2 bath in a unfinished basement. The house has a rough in for the bath with a tiolet opening in the floor. My question is what is the distance between the centerline of the drain and the wall in front of the tiolet. I know the back wall should be 12" from the centerline and...

View more questions Search