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Crankshaft Bearing(s)

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Old 11-23-2023, 11:46 AM
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Originally Posted by Jim Malcolm
You can get 0.001 undersized rod bearings on Rock Auto, but not main bearings.
Sealed power is the only brand I see that offers .001”. Anyone have experience with their quality? I can’t see anything that says if they’re tri-metal or aluminum.


Old 11-24-2023, 02:35 PM
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Originally Posted by Spencer_P
Sealed power is the only brand I see that offers .001”. Anyone have experience with their quality? I can’t see anything that says if they’re tri-metal or aluminum.

Sealed power is not the best. Tolerances can vary. The letters at the end of the bearing number tell you what material it's made out of. If it ends in an A, it's aluminum (bottom of the line). If it ends in P or CPA, it's a tri metal (standard for manufactures). If it ends in H it's a high performance version which I would not recommend for daily usage.
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Old 11-25-2023, 02:36 PM
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Looks like Mahle now has undersize in stock for $30 more than the Enginetech standards I ordered, but I'll wait to order until I've posted a picture of the markings. At this point looks like it'll be Tuesday before I get back to work on it and get a picture.
Old 11-27-2023, 02:22 PM
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Here is what the back side of each connecting rod bearing looks like. Would this be .001” undersize?

Old 11-27-2023, 02:25 PM
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#1 crank bearing cap lower bearing



Old 11-27-2023, 02:57 PM
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All upper connecting rod bearings are standard.




Old 11-27-2023, 07:17 PM
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Those sides of the bearings should be in pristine condition, looks like they might have spun. Make sure they are the correct ones for your model and year
Old 11-27-2023, 09:29 PM
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The tabs on the bearings are all intact, would that be possible if they had spun? Both crank and rod bearings are marked 99, the engine is a 99.
Old 11-27-2023, 11:50 PM
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I’m thinking it would be more obvious if the bearings had spun but I’m new to this and appreciate all the feedback. The crankshaft shop wants $185 to check and polish the crank. I guess I’ll rule that out and either polish it myself and run it with new bearings or start looking for a new engine…
Old 11-28-2023, 01:27 AM
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Looks to me like someone was mix matching bearings.... you have .001 on one side of the rod and STD on the other half? Definitely not the right way to do things. That will also fake out plasti-gauge readings (which is partly why I really hate that stuff). I am willing to bet if you put all standsrd size bearing back in, you won't have any issues. Please, go out and get a cheap digital caliper to measure with. Still not the right tool, but more accurate than the old school way.
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Old 11-28-2023, 07:37 AM
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Originally Posted by 5-Speed
Looks to me like someone was mix matching bearings.... you have .001 on one side of the rod and STD on the other half? Definitely not the right way to do things. That will also fake out plasti-gauge readings (which is partly why I really hate that stuff). I am willing to bet if you put all standsrd size bearing back in, you won't have any issues. Please, go out and get a cheap digital caliper to measure with. Still not the right tool, but more accurate than the old school way.
The FSM states that std and .001 can be used together to achieve spec. I have a caliper, what am I measuring? The bearing itself? I have std bearings that I can install and see what they do to the measurement. What do you think about the looks of the back side of the CR bearings?
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Old 11-28-2023, 08:38 AM
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If you are playing with bearings, I recommend a micrometer. Cheap af at pawn shops these days.
Old 11-28-2023, 10:35 AM
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Originally Posted by Spencer_P
The FSM states that std and .001 can be used together to achieve spec. I have a caliper, what am I measuring? The bearing itself? I have std bearings that I can install and see what they do to the measurement. What do you think about the looks of the back side of the CR bearings?
You will need to measure the crankshaft journals. Then flop the bearings in the rods, torque the bolts and measure the ID of it. Compare the differences and that will be your bearing clearance. An inside mic is what you really need to be 100% accurate but the caliper should get you pretty close.

Back side of those bearings looks terrible. It does look like they spun but if the tab is still there, they didnt spin. Maybe just loose in the rod letting it flop around a little. Is there any copper showing on the face of the bearings?
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Old 11-28-2023, 11:42 AM
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Okay, thanks I will measure with my caliper.

Originally Posted by 5-Speed
Is there any copper showing on the face of the bearings?






Old 11-28-2023, 12:15 PM
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Silly question and not sure if its relevant...is this a 99 engine or a 96 with 99 bearings in it? .002 clearance is plenty snug, wouldn't want to go down to .001 clearance and.003 is also plenty good. If you go through the trouble of miking everything..keep accurate readings and you can mix and match...entire bearings not Half and half like PO. Hate to say this but if crank bearings / rods were scored, you have no idea what your cam and bearings look like. If your pulling crank...you might as well pull cam


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