Main Bearings ? 2f 1976

Joined
Dec 9, 2018
Messages
257
Location
Upstate NY
Just look at this old bearings.. how with this bubbles come out?
why crankshaft didn't cut them out.. ?

IMG_9216.jpg

.. zoom
IMG_9216a.jpg
 
Joined
Nov 25, 2014
Messages
387
Location
Western victoria Australia
 
those pits appear to be on the backside outer part of the bearing shells. the crankshaft doesn't contact them there. Or that's how the pic seems to me.
It's like an optical illusion lol. I look at it once and then again it appears to be the inside of the shell. so ignore the first part of my post:oops:
As to the question, I have seen similar pits in worn bearings before. Sitting for ages without running can cause corrosion on the surface of the shells.
and the majority of the surface area of the shell is not pitted, so it would take a really long time to wear smooth.
 
Last edited:
Joined
Dec 9, 2018
Messages
257
Location
Upstate NY
those pits appear to be on the backside outer part of the bearing shells. the crankshaft doesn't contact them there. Or that's how the pic seems to me.
It's like an optical illusion lol. I look at it once and then again it appears to be the inside of the shell. so ignore the first part of my post:oops:
As to the question, I have seen similar pits in worn bearings before. Sitting for ages without running can cause corrosion on the surface of the shells.
and the majority of the surface area of the shell is not pitted, so it would take a really long time to wear smooth.
Thanks, it make sense. I'm assuming don't take the risk to re-use it...
 
Joined
Dec 9, 2018
Messages
257
Location
Upstate NY
I got a new main bearings. Do I need to check all of them with plastigage?
manual said.. "if clearance is not with specification replace bearings".
I guess if clearance is not with spec after replacing them... I will need a new crankshaft..?
 
Joined
Nov 25, 2014
Messages
387
Location
Western victoria Australia
 
SergP , full engine rebuilds can be daunting. A machine shop would give you an idea of the condition of the crank etc.
Or you could do what I do, and chuck the new standard shells in, torque down, and if the crank turns freely, good enough:cool:
Probably not good advice . I have never replaced main bearings in an F engine before.
If the plastigage shows clearance is way off, a crank grind is always an option.
Good luck.
 
Joined
Dec 9, 2018
Messages
257
Location
Upstate NY
SergP , full engine rebuilds can be daunting. A machine shop would give you an idea of the condition of the crank etc.
Or you could do what I do, and chuck the new standard shells in, torque down, and if the crank turns freely, good enough:cool:
Probably not good advice . I have never replaced main bearings in an F engine before.
If the plastigage shows clearance is way off, a crank grind is always an option.
Good luck.
Thank you. I will look what the plastigage shows.. maybe I worry too much :rolleyes:
 

Casey E

SILVER Star
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Jul 11, 2013
Messages
1,238
Location
Washington
 
I have had PG show to tight and switch out another new bearing and be fine. I would just give crank a good visual once or twice over and go from there. Crank should be fine unless a bearing spun or some other issues occurred like dropped crank on ground.
 
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