LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Mileage on Cam Bearings

Old May 11, 2009 | 07:53 PM
  #21  
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Originally Posted by ss.slp.ls1
What exactly do you mean by freshen up the bottom end? If you are thinking about doing what I think you are, you might as well drop the motor and do a full rebuild...you can't simply pull the crank and install new main and rod bearings, you need to get the block machined.
Not really, people get by all the time by swapping out bearings that are either worn out or just to do while they have the pan off. If their was no other problems their is no need to machine anything, now if it spun a bearing that is a totally different story.
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Old May 11, 2009 | 07:58 PM
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Originally Posted by My95Z
Not really, people get by all the time by swapping out bearings that are either worn out or just to do while they have the pan off. If their was no other problems their is no need to machine anything, now if it spun a bearing that is a totally different story.
Yes really. People get by all the time =/= what you should be doing.

Your rod ends and mains will likely be slightly out of round. This will only accelerate wear on the new bearings. If you are going to get new bearings, you need machine work, simple as that. You can "get by" all you want, but I prefer to do things right.
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Old May 11, 2009 | 08:09 PM
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But sometimes the difference b/t doing things right and getting by is several thousand dollars, and in an engine that was running fine before and they just wanted to "freshen up" as a preventative measure they will be fine. Yes you can argue that the rod end may be slightly out of found all day, but the bearing will conform to the surface as long as its not really distorted, like I said, if the engine had an exhisting problem this would not be a good idea and would buy a few hundred miles at most, but in a good engine it would be fine.
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Old May 12, 2009 | 04:55 AM
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well i've seen it done and the cam bearings are smooth but not silver they are copper in color .. they dont look like they have had hazing or burning like you would see by metal to metal contact ... it is a 80k long block and i wanted to change them out just to be on the safe side while my other block is getting fixed.... and that will be awhile as it is costly but if i can spend a hundred bucks to insure that my bearings dont go down them i will do that because i wana drive my car while i can till my motor is fixed the way i want it... can i just pulled the crank and put it back together with the same bearings aslong as i retorq them o specs or i am budget minded and i would love to just have the cash to throw around but ... i''m poor
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Old May 12, 2009 | 09:40 AM
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I guess you could pull the crank and replace with the same bearings, but I wouldn't. P series bearings are only about $40 for a whole set (main and rod) and as long as you verify they have the right clearances just throw in a new set and torque it back down. From what you're describing from the wear on the bearings I would def swap them out, it doesn't sound like normal wear.
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Old May 12, 2009 | 02:12 PM
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plastigage them or no ? and what do you mean p series that a heavy load bearing?
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Old May 12, 2009 | 03:35 PM
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Clevite P series bearing is most likely what you want to use for the build. Yeah, I would at least plastigage them to ensure you have good clearances.
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Old May 13, 2009 | 04:15 AM
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.25 and .26 clearance on main and rod right
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Old May 13, 2009 | 11:16 AM
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Yeah, I like to run the back and front most main bearing a little looser than the rest, but as long as your mains are around .0025 and rods are around .002 you'll be fine.
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Old May 13, 2009 | 07:09 PM
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I have 176K on my original bearings and still carry 50 psi of oil pres. That's with a mechanical Autometer Phantom II gauge.
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Old May 14, 2009 | 12:37 PM
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well as soon as i get the money im tear it down and replace them ...i'll keep you informed
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