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Reusing Main Bearings

Other than measuring. What would preclude me from reusing my main bearings. One of them has a scratch that you can catch a finger nail on. A few also have "hot spots" on them. Is it just safer to get new bearings?

If I was to reuse I was thinking of having them coated here. http://swaintech.com/race-coatings/automotive-coatings/automotive-coatings-price-sheet/
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Last edited by arbita1; 07-03-2016 at 04:46 AM..
Old 07-03-2016, 04:44 AM
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You can, but why go to all that work and put used bearings in?
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Old 07-03-2016, 09:34 AM
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If the bearings are more than a few years old, you are wasting your time, FMI, re-using them. (don't ask how I know)
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Old 07-03-2016, 12:17 PM
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I have had the same thought, but Why? The cost of new bearings is slight in comparison to a full rebuild
Old 07-03-2016, 01:20 PM
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Others have recommended it. I hadn't even thought of it until then. Ok. New bearings it is.
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Old 07-03-2016, 05:30 PM
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I've re-used #8
The tolerances on new number 8 bearings are horrid. At least the ones I've seen.
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Old 07-03-2016, 06:27 PM
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Hi,to obtain a perfect fit they should only be squashed once and not reused.Fred
Old 07-08-2016, 04:06 AM
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Quote:
Originally Posted by faapgar View Post
Hi,to obtain a perfect fit they should only be squashed once and not reused.Fred
Don't agree. In the course of a proper engine build, the rod bearings are assembled in the rods out of the engine and torqued to measure the ID "as installed" with a precision bore gage. Likewise, the case halves are assembled with bearings, but nothing else to measure the ID of the mains. Once the crank is mic'd and clearances are calculated to be acceptable, then final assembly can proceed for real. I have never heard of this trial fitting for measurement to cause any harm. Likewise, a couple of times I have dissembled engines that had very low miles to fix specific problems and reused all the bearings because they were virtually as new. Had no problems with that either. I'm not saying that I wouldn't replace the mains in this case - I would - I just have never experienced problems reinstalling bearing shells that have previously been installed and torqued.
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Old 07-08-2016, 07:58 AM
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So I've seen some reinstall their number 8 bearing. How do I determine if I can reuse mine?


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Old 07-16-2016, 05:48 AM
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I recommend always installing new bearings...as JW said "why go to all that work and put in used bearings"........and I use the "trial fitting/bore gage" method to determine bearing clearances/specs etc.

regards,
al
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Old 07-16-2016, 08:18 AM
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Quote:
Originally Posted by arbita1 View Post
So I've seen some reinstall their number 8 bearing. How do I determine if I can reuse mine?


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I reused mine since:

1. It's a very large bearing with lots of load surface
2. It's way overpriced
3. There's very little load on it vs other vehicles

Didn't put much more than thought than that
Old 07-16-2016, 10:03 AM
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It should be measured with a bore gauge, but the down and dirty is it should slip on but have no play if you rock it side to side.

I bought 4 new 930 #8 bearings from different sources, they were all over spec with the worst being almost a full half mm too big.

Since my old bearing was in spec I DFL coated it and reused it.
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Old 07-16-2016, 01:10 PM
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