Oil Pump Relief Valve Shimming

The cam bearing is toast on my '71 travelette. Found the pieces in the pan. So being rather handy, but never having done a cam bearing, how would it be replaced? And is it likely a new cam will be needed. Still driving the truck, just low oil pressure.

I know the process of pulling the lifters and front cover, it is the actual install of the bearing. Also since it happened, what causes it and how can one prevent it from happening again???
 
Well chappie the major cause of cam bearing failure in IH motors from what I can tell is improper revival of an engine thats been sitting, and just plain ol wore out.ive also heard that there was a delaminating issue but who knows if thats true! If your gonna replace the bearings, yank it out. The cam May be good but you can get a new kit cheaper than you can pull it and do it again. The cam bearings drive out and back in.
Imho, you can install the bearings with the proper tool and some in depth study of the oil hole placement. Also remember that the rear bearing needs to be cut into the rear oil port to feed the lifter valley, all in the rocker thread. As far as preventing this, proper oil maintenence and cranking the ol beast at least once a week will do the trick, no way to preent natural wear out, its inevitable.
Every thing you need to know is here and in the manual. Wish I was closer to alot of the guys on here I love this stuff and resurrecting these ol beast makes my heart happy. Guess its in my blood!
 
Just to clarify tow's point...by yank it out, he means the engine. This job must be done with the engine pulled. The cam bearings are replaced as a set, not just the one that failed. Unless the cam and lifters were recently replaced and still within spec and no abnormal wear present, you May as well figure on replacing those too, since they've got to come out anyway. Re-installing worn out parts at this stage is false economy.
 
This engine was rebuilt at one time and is still very tight with no smoke and good compression. That's a bummer about pulling the engine, I was hoping just the front bearing could be replaced with it in the truck. Of course if I'm going to pull it I might as well go through the whole thing, or drive it until it dies. As far as I know it's been working fine that way for years.
 
Even if only one has failed, you're likely to see de-lamination and/or obvious signs of wear on others. There's much to be said for having surfaces in frequent or constant contact wear together such as the cam shaft, lifters, and cam bearings. These engines have been known to run quite awhile in this condition, but yours will eventually experience catastrophic failure if let go long enough.
 
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