no thanks.....
Anyone seen one like this?
Thread Starter
Team Owner
Joined: Aug 2006
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From: Columbia Missouri
Anyone seen one like this?
This is a #2 rod bearing. I have never seen one look this bad. Anyone seen carnage like this without it actually damaging the rod cap?
This blew my mind. It was almost one piece.
This blew my mind. It was almost one piece.
Last edited by Durango_Boy; Dec 19, 2007 at 06:34 PM.
Thread Starter
Team Owner
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From: Columbia Missouri
Team Owner
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From: Crossville TN
I doubt that the crank journal that bearing came from is "OK". It may not be scored or distressed LOOKING...but the heat that came from that bearing surely did so tempering to the heat treatment on the surface of the journal. If there was any discoloration of the journal at all, I'd carefully consider whether I wanted to use it again [or not]. P.S. You don't want to check hardness on a finished journal, as the indent mark made will become a stress riser and could eventually propagate a crack.
Le Mans Master
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From: cincinnati ohio
St. Jude Donor '09
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Burning Brakes
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Thread Starter
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I doubt that the crank journal that bearing came from is "OK". It may not be scored or distressed LOOKING...but the heat that came from that bearing surely did so tempering to the heat treatment on the surface of the journal. If there was any discoloration of the journal at all, I'd carefully consider whether I wanted to use it again [or not]. P.S. You don't want to check hardness on a finished journal, as the indent mark made will become a stress riser and could eventually propagate a crack.
Both myself and the machine shop checked everything out. The block and the caps and rods were all checked and checked out okay. They only damage was to the bearings and crank journals.
I emailed the customer with pics and recommendations from the machine shop and he decided he didn't want a -.030 crank so I bought a -.010 crank. I discussed the level of turnings with the guys there, and they said that .030 is the most they will do but that it's just as safe as a .010 so long as it's not a high RPM racing motor.
Team Owner
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From: Crossville TN
Heat treatment depths on crank journals are in the .015-.020 inch range (only hard at the surface for wear resistance; core hardness is much lower for toughness). If they go deeper than that, you run the risk of having a "brittle" crank. Grinding .005 off the journal would be better [if it cleaned up OK]....010 would be the max, IMHO. If you do regrind the journals, make sure the fillet radii at the edges of all journals are smooth and blended. They are a great place for cracks to start if you don't. Good luck.
Drifting
Joined: Sep 2007
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From: Wichita Kansas
I doubt that the crank journal that bearing came from is "OK". It may not be scored or distressed LOOKING...but the heat that came from that bearing surely did so tempering to the heat treatment on the surface of the journal. If there was any discoloration of the journal at all, I'd carefully consider whether I wanted to use it again [or not]. P.S. You don't want to check hardness on a finished journal, as the indent mark made will become a stress riser and could eventually propagate a crack.
DB,
Chuck that crank and go with a new one. May look good afther machining, however I would take the concern of hardness serious.
Thread Starter
Team Owner
Joined: Aug 2006
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From: Columbia Missouri
See above...after taking what I knew back to the customer, he decided the extra money for the -.010 crank was what he wanted over the -.030.
Thread Starter
Team Owner
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From: Columbia Missouri
Burning Brakes
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Now I am totally lost. Is there some probation here? There seems to be alot of wierd comments here I just do not understand yet.
Le Mans Master
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