Bearing Problems-BBC
#21
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See page 402, line 108:
http://www.mahle-aftermarket.com/C125790900540AC0/vwContentByUNID/58A5032D3003098AC12579AB00615520/$FILE/EB-10-07.pdf
At any rate, It's not gonna work for him anyway, as all five bores are +.020. Like you guys said, I do believe King makes the set he needs.
#22
Geronimo36
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The saddles were probably hurt beyond that point. Not a good idea to move the crankshaft centerline that much... It becomes more than a .005 or .010 short timing chain can compensate for. The bigger issue with a one piece rear seal block, such as a Gen VI, is that the crankshaft centerline moves up, but the rear seal does not... ie: rear seal leak. Boring the main housing bores oversize has become more commonplace with most engines being one piece rear seal. On a Mark IV block, the seal retaining area is the same dimension as the housing bore... when you cut the cap and hone the bore to std. size, the seal area size and alignment is corrected along with the housing bore.
#23
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I just can't believe that this isn't a common way to fix this problem with oversize bearings. It is the solution for turned cranks, why not for the more expensive to replace part, the mains? .020 is not a whole lot to have to thicken a bearing.......
I did find that King makes a set....but not in their performance series bearings.
MB5274SI it is an Allecular Silicon bearing. Is this strong enough for a 600 hp marine application? King's web catalog sucks by the way.
I did find that King makes a set....but not in their performance series bearings.
MB5274SI it is an Allecular Silicon bearing. Is this strong enough for a 600 hp marine application? King's web catalog sucks by the way.
Last edited by Gimme Fuel; 05-16-2012 at 09:33 AM.
#24
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King MB5274SI is probably what you will have to use. I would not be afraid of using those bearings as long as you are not making outlandish HP. Also, depending on which crankshaft you are using, you might have to put a chamfer on the bearings to clear the radius on the crank.
#25
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#26
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King just responded to my custom bearing request........500 minimum order. Anybody need over-sized bearings?
Going to give Odessa Babbit a call......they claim they can make any bearing.
Going to give Odessa Babbit a call......they claim they can make any bearing.
#27
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King MB5274SI is probably what you will have to use. I would not be afraid of using those bearings as long as you are not making outlandish HP. Also, depending on which crankshaft you are using, you might have to put a chamfer on the bearings to clear the radius on the crank.
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#29
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#30
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I am almost certain that the last couple of 502's that I have worked on had King bearings in them from the factory. They were both "freshen up" deals and did not need the crankshafts reground so I wanted to put the same exact bearings back in them that came out. After a bunch of measuring and comparing, I pretty much came to the conclusion that the oem bearings were King. After looking at bearings for 25 years you sort of get to know which is which, they all have thier tell tail characteristics even without part numbers.
I think that those bearings would work just fine if they are run with the proper clearance etc. Unfortunately for you, the machine work has already been done so you will have to live with whatever clearance you end up with unless . . .
What I would do is get the King bearings but in .010" undersize. Then you can bolt them together and measure them and have the crankshaft reground to give you the clearance you want to run.
Your other choice is to get the King bearings for your standard crank and see what you have, but if it isnt right you will be stuck with those bearings.
Not sure what other choices you really have
Last edited by BillK; 05-16-2012 at 10:49 AM.