Brand new main bearing nicked. Usable?

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The center 3 mains are the weakest, due to not being incorporated in the front and rear block walls , and the bottom shells do receive the most ponding.
If u think there is no stress on # 3 thrust bearing in a hemi or big block, why do they go south occasionally in hi h.p. , hooked up drag cars?
It was enough of a problem that the Chrysler drag seminars had some teaching on them back in the day . Most teams back then changed bearings on the prostock type cars regularly.
I lost a thrust bearing in a hemi s/s car once and learned of the problem from Tom Hoover.
Of course a lot if u younger guys probly don't even know who he was.
He was called the god father of the hemi.
Things have come a long way since then tho in engine and bearing design , I guess-----------
What do you call the webs where the main cap bolts go, between the insert saddle and the oil pan rail? As far as the stress on the center main, look at the firing order and see how many combustion cycles hit that one in one revolution. The reason why Ford had a different firing order for the old 302 to the 351 windsor and the later year 302. Chevy changed from the old 18436572 to the later LS and Gen V BB with the 4/7 swap to move half of the load to the front and rear mains.
 
What do you call the webs where the main cap bolts go, between the insert saddle and the oil pan rail? As far as the stress on the center main, look at the firing order and see how many combustion cycles hit that one in one revolution. The reason why Ford had a different firing order for the old 302 to the 351 windsor and the later year 302. Chevy changed from the old 18436572 to the later LS and Gen V BB with the 4/7 swap to move half of the load to the front and rear mains.

Regardless of what you say , there is more strength in the front and rear of the block , than the middle , even bill jenkins said so in one of his performance books .
 
Regardless of what you say , there is more strength in the front and rear of the block , than the middle , even bill jenkins said so in one of his performance books .
I totally agree aside from the case with the LA block in the front ! Which is one of many reasons, main girdles came about in the first place. Then there is the famous SBC where they only gave use 4 bolt mains in the center 3, go figure, BBC has 4 bolts on all 5 in the 4 bolt version. It's been too many years since I last saw a Pontiac Super Duty with 4 bolt mains so I can't make statement here. We all know that technology usually moves forward as in the case of the newer engines like the 4.7, 3.7, 5.7 and LS blocks and tritons along with the wonderful little GM 3800 all with cross bolted mains. There are many others with this added engineering, Nothing much anyone can do with the old LA front upper region with all that iron drilled out for oil passages though. No main girdle is going to help cracking with those engines. But on the topic, the mains do have webbing and support in the center and with the block basically made triangular in design, double wall if you take into account the cylinder walls and water jackets, there is a lot of iron or aluminum to have to flex. Now looking at a 4.7 a very nicely engineered engine, a little help from Mercedes there, with a full lower block support arrangement, well technology absolutely improved ahead there, to bad it went lightweight everywhere else. I dont like fractured forged powered rods as much as fully forged steel although they do well to hold bearing inserts from scuffing and loosing preload. If you want to see an engine that is really built to eliminate issues in crank support just look at a Kubota. No free mounted main caps as with most engines, bearings are mounted in a split circular support which slides in from the end of the block as an assembly then bolted 90 degrees from the bolts that hold the bearing retainers together around the mains. If someone would take this design and incorporate it into something we could and would build for high perf. blocks that can be fitted to something like an A,B,E forget the old F bodies, that the fenders come up in the back if bounced hard because of how the torsion bars where designed, or any other popular offering from any of the makes of muscle cars.
 
The lower bearing is THE main load bearing shell at each main.

Scrape lightly as suggested. Then use it, IMHO. I personally would not further use Scotchbrite, nor worry too much over what you have done to this point. Inspect the bearing with a magnifying glass if you think anything embedded in it.
I read an engineering paper recently that contends the upper bearing shell sees more load than the lower...

Don't take King off of your speed dial. Good stuff...they make bearings no one else offers and they may help you sometime in the future.

That nick in your bearing is inconsequential. Its like a fly speck on your windshield... fix it and you are golden. If you have a used shell pair them up and measure... you would be surprised how many race motors are assembled with mis matched bearings to get clearances correct.
 
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I read an engineering paper recently that contends the upper bearing shell sees more load than the lower...

Don't take King off of your speed dial. Good stuff...they make bearings no one else offers and they may help you sometime in the future.

That nick in your bearing is inconsequential. Its like a fly speck on your windshield... fix it and you are golden. If you have a used shell pair them up and measure... you would be surprised how many race motors are assembled with mis matched bearings to get clearances correct.
That must be why the lower shell always look the worst? Consider this, if an engine has an excess of clearance in the mains, when you let off the throttle you can or should see the oil pressure resize a little. The lower shells always wear more then the uppers, I garantee it. Also, what produces the most stress in a rotating engine? The load during the combustion cycle while the piston is pushing the crank around after TDC !!! NO one can argue that fact with any intelligence! In over 40 years of working on engines the only time I saw a bearing with the upper shell looking worse then the lower was in a 3406 Cat with a bent crankshaft. In that engine there were a couple of upper shells that looked worse because the crank would lift against the uppers when on the exhaust cycle. If there were any other times a load were present, you would not have an engine producing torque and HP. It would be nothing more then an air compressor. Even so, with either of those, the major load is on the bottom shell period. The only time the load on the upper shells exceeds major lower load on the lower shells is when you are decelerating or going down a hill with your foot off the throttle, at which time the engine becomes a vacuum pump!
 
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