cam bearings in GM LS engine

[PLohr]

Hello,
I am beginning a rebuild of a 2008 6.2L LS engine. This is intended to be a stock rebuild with upgrades for durability where possible. I understand that cam bearings are 'finished in place' in these motors by GM. The engine had 200K miles on it and the cam bearing clearances are as loose as 0.006". So something probably needs to be done with the cam and / or cam bearings.

Should I find a competent machine shop to align bore the camshaft bores, then get the oversized cam bearings from Dura-Bond?

Another option would be to install OE cam bearings and check the camshaft for tightness as it rotates. Not exactly scientific.

The camshaft runout at the journals is 0.001". GM says 0.001" is the limit so the cam may be questionable.

I'd like to get another 200K out of the rebuild if possible.

Thank you for any help,
Paul Lohr

[CGT]

The O.E bearings will cost you close to 200.00, they are sold individually and arent cheap. Although LS's can be a pain installing new bearings they aren't always. I just did a 6.2 that I had to fight with a bit but it worked out.

The narrower bearings, I used sealed power this time, seem to be more forgiving than the wider OE bearing. Align honing etc would be a last resort for me, I haven't had one that required that yet.

[BillK]

The narrower bearings, I used sealed power this time, seem to be more forgiving than the wider OE bearing. Align honing etc would be a last resort for me, I haven't had one that required that yet.

Actually the narrow ones have all been superseded to the wide ones. The early oem ones were narrow also. I really have not had any problems with any of them. I use Durabond. Only thing you have to watch is on the aluminum blocks it seems like the oem bearings leave a pretty good scar in the bore where the joint in the bearing is. I always take a sanding roll and smooth it. Every one I have done has been a little loose from the get go but it does not seem to hurt anything. They are like that from the factory.

[CGT]

The narrower bearings, I used sealed power this time, seem to be more forgiving than the wider OE bearing. Align honing etc would be a last resort for me, I haven't had one that required that yet.

Actually the narrow ones have all been superseded to the wide ones. The early oem ones were narrow also. I really have not had any problems with any of them. I use Durabond. Only thing you have to watch is on the aluminum blocks it seems like the oem bearings leave a pretty good scar in the bore where the joint in the bearing is. I always take a sanding roll and smooth it. Every one I have done has been a little loose from the get go but it does not seem to hurt anything. They are like that from the factory.

Ok, I must still be getting old stock. Why can't they just leave stuff alone? The factory replacement ones now are coated, very nice looking piece.

[PLohr]

Thanks everyone for your help.

Any thoughts about align boring the camshaft bores so that the cam bores are concentric to each other and parallel to the crank center line?

If you were going to sell a 200k mile warranty on such a motor, would you go through with align boring the cam bores?