Cam bearing...do I really need to replace?
I'm not 100% sure on the L76. However the front cam bearing looked like this on my LM7. Asked around on pt.net and they all said it's completely normal. Threw my new cam in and it's got about 10k on it with no issues.
My L92 looked like this also and were the #1 reason I tore apart the engine and rebuilt it. I suspect the AFM lifters contribute to the bottom wear with their extra spring pressures on the cam to keep them in contact when AFM is engaged..
I don't like doing things twice so I replaced, YMMV..
I don't like doing things twice so I replaced, YMMV..
I wouldn't be as worried about cam bearings as I would of any other bearings in the bottom end, in fact, I don't think I've ever seen the cam bearings (at least the front ones) look "good" on any small or big block I've ever opened up...but man, be cleaner!!! There's a lot of dirt in there on the block casting surfaces...stuff like that will contribute to an early failure.
On The Tree
Joined: Aug 2010
Posts: 129
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From: indiana
My 65k LS has copper showing as well. Mines more on the side than the bottom. But, the way i see it, you can buy a set of Dura-Bond bearings for ~$40. thats pretty cheap insurance if you ask me....Id go ahead and replace them since your already that far...
Banned
Joined: Aug 2006
Posts: 326
Likes: 0
From: North Bay, CA
Those are worn out, and it's quite common on these motors - I always use the Durabond Teflon coated bearings. If not now, it will soon cause a pressure drop across the whole system if you don't replace those.
As was said, you need to really spend some cleaning time in there.
As was said, you need to really spend some cleaning time in there.
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TECH Fanatic
Joined: Jun 2011
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From: Katy, TX
Banned
Joined: Aug 2006
Posts: 326
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From: North Bay, CA
Unless that picture is tricking me, there's a wear ridge on the backside of that front bearing, and I've only seen a couple low mile blocks with a similar look to the bearings - they measured over .004".
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
FormerVendor
Joined: Nov 2001
Posts: 3,065
Likes: 6
From: Houston, Tx.
It probably does have a little wear but they really do always seem to look like that for some reason on the GM OEM bearings. They look worn out when they are right out of the crate brand new!?!
Way, way back in early '02 I had a non-LS shop do a cam swap for me on my T/A at 10k miles. They called mid-process saying 2 of the cam bearings had copper showing and needed to be replaced (hell you can probably search my s/n and find that thread) and yanked the motor out. It was not much wear showing, less than the OP's pic, but I was young and dumb and had them do it. Most on here thought nothing of the wear, and watching threads like this I've come to find over the years it's the norm for an LS with virtually any miles on it. I can only recall of like 1 person ever having a cam bearing spin on them. Needless to say my shop experience chapped my *** pretty bad and I've done virtually all my own work since then.
Copper showing on brand new cam bearings is normal due to line hone at GM (I was told by a very reputable shop in Detroit). Looking around their shop was a few brand new LS7 blocks and they all had the same condition. I wouldn't touch the bearings unless you absolutely have to. There are multiple horror stories on this board about incorrectly installed aftermarket bearings causing them to spin.
I've torn down a bunch of LS engines and have never seen one that did not have that type of wear showing on the cam bearing. It is nothing to worry about. I've heard the story about GM line honing them. Which seems very logical.
