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Tearing down a recently rebuilt engine and discovering all kinds of Easter eggs. This one could be the cause of my low oil pressure! None of the other bearings are visible and this one was walking right out. So, I have to assume that this wasn't installed this way, so what's next - I take this in for a resurfacing of the cam journals/housing, then I'll need custom bearings to make up the new width?
It’s definitely the cause of your oil pressure issue. Cam bearing walking is unfortunately fairly common, especially in aftermarket cam bearing installs. The cam bearings go in with a certain amount of crush, and it’s the crush that retains the bearings. Three things here have transpired…either the bearing spun because the cam journal diameter to bearing clearance was too tight (or cam was slightly bent…VERY common)…OR the bearing had a taper to it on the journal side, and the taper forced the bearing to walk out because of oil pressure….meaning it was hydraulically pushed out instead of down….OR lastly, the wrong bearing was pressed into the wrong journal. Bearing journals are 3 different ID’s and the correct OD bearing must go into the corresponding journal. There’s a very specific order of which bearing goes where, in other words.
Unless your doing your own work, have a shop decipher what happened here. If the bearing housing bore is damaged from the bearing spinning, it’s really not financially feasible to repair it. It would be much cheaper to source another block.
Thanks Che70velle - if the guy who built this wasn't 200 miles away I'd drop the block in his front yard. This is not the first botch on this build. The cam turns and slides around easily in the bearings, so I don't think it's a clearance problem. Hopefully that means it didn't spin and damage the bore on the way out. Contacting a shop today to get on their schedule.
It turned slightly, looks like oil hole was mis-placed on the top of the bore (picture taken from bottom), and the oil pressure pushed it out, like you said may happen.
The bearings typically have 2 holes in them. One on either side. Check out how the lifter chewed a couple notches in the bearing as it turned. The engine is full of shavings. Oil filter will be a mess with debris. Bearings should be pretty scarred. Stinks man.
Wow-What # cam bearing is this? I had my rearmost, #5 cam bearing walk forward far enough to uncover the oil hole. Instant total pressure loss. Sorry to see all your troubles. If its any consolation, it took out my entire motor. If that bearing bore is OK, and your pistons and cylinders are serviceable, you've dodged a huge bullet!!
Last edited by grinder11; Dec 6, 2023 at 07:28 AM.
It's #2 bearing. #4 also pushed out a little but not enough to obscure the oil hole. I'm surprised that there isn't more wear on the journals and bearings. This must have happened during break-in because I never noticed any metal in the pan bottom (it's a corvette pan so the bottom is removable) after the first oil change, and I was checking often when the pressure started to drop. Probably helps that I was changing the oil constantly, not proud of my carbon footprint last year. I attached a shot of the cam journal from that walked bearing and a couple shots of the crank and bearings. You can see more than normal wear on the cam lobe that was pushing that lifter.
What are you going to do with it send it or do the work yourself and try to set some quality cam bearings? I am curious what is going on with this part of the block?
I'm going to bring to it to a shop. I've contacted ABT Machine in Holliston MA and they've agreed to take a look in January.
I am curious what is going on with this part of the block?
An expert can probably confirm, but I think all LS blocks have similar material removed, at least the ones use a PCV system off the valley pan cover. It looks like a hack job but I believe it's factory.
What are you going to do with it send it or do the work yourself and try to set some quality cam bearings? I am curious what is going on with this part of the block?
It is a factory intersection cast into the blocks. Somebody opened this up with a grinding tool of some sort, and didn’t smooth it. I always open up this area, one, to remove all the casting flash, and two, for better cross breathing between the ends of the block.
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Got a cam bearing issue 
