Johnnypac

I got the new king main bearings (MB5293SI )
in and just put them on… They are not a whole lot better
.001....
readings are the same across the 5 bearings and are even across each bearing....

I can't tell you how many hours I've spent googling this.
It makes no sense, both sets of bearings are standard, he polished the crank… if anything, they should be a bit loose…

RedXray

Glad the Kings worked out.
I've read where the factory uses two different bearing sizes on the main caps to get the spec they're looking for, whereas the block gets only one size. You may have gotten an engine with a slightly larger journal size that required the looser bearing on the main caps to get the clearances correct. You ought to have some great oil pressure lol. Mine never drops below 58 lbs at idle with the .0015 main clearances running 10w-30

Johnnypac

Im looking to get .002-.0025....
i'm gonna take it back to the machine shop and have them take some off the journals.

MikeGyver

iTrader: (5)

Why? Are you going to run gear oil in the crankcase? This is an LS based engine. Where did you come up with those numbers? The GM service manual says that if the bearing clearance exceeds .00212 that you should replace the crank or grind it for the next undersized bearings. The production clearance specs are .0007 - .00212. As RedXray said, glad to hear that the Kings worked out for you.

Johnnypac

I was thinking, and meant to say .0015-.002....

ok, so it sounds like im good....
that's reassuring.
im gonna mic it next week to get better readings and for piece of mind.


thanks for the insight

RedXray

Here is the manual for the 6.0 engine.

You didn't say what you were building but a good bit will carry over to the 4.8 and 5.3 but you'll need to double check the spec numbers if you're not building a 6.0

EDIT TO ADD: I see in the title it's a 5.3... still a good read.

Johnnypac

Awesome, thanks RedXray....
i have an LS rebuild book and it's been great, but i'm sure this will be more useful.