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Quote:

Originally Posted by BillK (Post 3688318)

CI,
I dont think this is the case, but the thrust might be .010 wider. I have done this to several blocks and all five bearings are the same crank journal size.

The Clevite MS1748P is only oversize on 1-4. The thrust uses std housing bore... It's kinda goofy that they do it that way... It's got a standard thrust width, but it's not available in std shaft size... only .010 and .020. OP made the comment that his mains were std, that's why I stated he'd have to grind the mains .010.

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.

Quote:

Originally Posted by cubicinches (Post 3688165)

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.

Good info, thanks for posting!

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.

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.

Quote:

Originally Posted by cubicinches (Post 3688172)

Only problem is, as I stated above, is that only 1-4 are over size... .

Boy, that is really strange that Clevite does it that way. Would pretty much mean that the block would have to be align bored and not honed to finish size.

King just responded to my custom bearing request........500 minimum order. Anybody need over-sized bearings?:lolhit:

Going to give Odessa Babbit a call......they claim they can make any bearing.

Quote:

Originally Posted by BillK (Post 3688786)

What is considered OUTLANDISH? Talking under 650 hp here....but heavy throttle handed driver:rolleyes:

Quote:

Originally Posted by BillK (Post 3688807)

Boy, that is really strange that Clevite does it that way. Would pretty much mean that the block would have to be align bored and not honed to finish size.

Exactly... Doesn't make much sense.

Quote:

Originally Posted by Gimme Fuel (Post 3688831)

King just responded to my custom bearing request........500 minimum order. Anybody need over-sized bearings?:lolhit:

Do they consider that a custom bearing? It's in their catalog.

Quote:

Originally Posted by Gimme Fuel (Post 3688834)

What is considered OUTLANDISH? Talking under 650 hp here....but heavy throttle handed driver:rolleyes:

I know of a couple that have been modified to at least that horsepower level and are using the "normal" King bearings.

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 :(