Cam bearing failure 440/6 (repost)

I posted on this issue earlier.

On my 440 the bearing failed on the #4 Journal (this oils both rocker arms), determination into the failure was the installed bearing was to tight of a press fit causing the bearing to wear prematurely. Current measurement of the Journal opening is 2.0800. Opening should measure 2.0835. I have a few options to fix this problem:
1. Locate a "under sized OD" bearing to fit the current journal opening and my cam shaft.
2. Purchase a new bearing and machine down the outter race to get a solid fit into the journal yet not affect the inner race dimension so the cam fits properly with no binding or overly tight fit. If I go this route what is the best way to machine down the outter race of a bearing?
3. What is the best way to remove Journal material for a correct bearing to fit into? (this method is not that appealing to me)
4. Who is a knowledgeable souce on cam shafts, someone who has extensive experience in cam/bearing applications, they may have options I'm not familiar with or know where I may get a correct size bearing. Thanks.

Every big block I have built had tight cam bearings.
Did one engine with King cam bearings, and one of the bearings would not fit over the cam journal uninstalled (just checking to the cam?) I didn't measure the cam journal size, but it may have been too large?

Just have the hole fixed, it's not that hard to do, I don't think you are going to find an undersize OD bearing, this not an unusual thing, after the block has "SEASONED" you may find the cam tunnel is slightly shifted and/or out of round.

This whole concept of "outer race" is incorrect. There are only two parts to a journal bearing, the journal and the bearing. In the case of a cam bearing the bearing is called a bearing insert or shell.

Machining down the OD of the bearing insert is impossible. Period.

JohnRR is right, fix the cam bores in the block.

This is not a big problem, and seems to affect certain engine families more than others. B/RB engines are one of the families that is affected. Deal with it.

R.

This problem is common on Mopar BB Two choices that I know of to take care of the bearing and cam fitment issue, one is to have the cam tunnel honed to the proper size and the other, which is what I do now, is to buy a bearing scraper and scrape the tight bearings (a little at a time, don't take big cuts ) until the cam turns easily IHTHs As already said, try the new bearings on each location on the cam before installing them and then install one cam bearing at a time and check the cam fitment, fix the bad ones first and then go to the next one To bad Ma Mopar screwed the pooch on this issue

you have to hone to the correct size
most of my motors were like that
i just hone them to size fit the bearing and make sure the cam spins good

Very common problem.I find that maybe 1 in 5 will work without some scraping etc.Sometimes you can press one in and it will be tight remove it and put another in and its ok.One thing that helps is to use a babbit cam bearing.They are the ones that are pressed into a circle and have a seem that you can see on the back side.Factory bearings were of that design.They conform to the block better than the seemless Durabond type bearing.I use an old cam (check straightness) that has a groove ground across each journal.Short of align boring the bearings after they are installed it is the most accurate and easiest way to fix this problem.

One more item that helps is the tool that is used.The Kent-Moore style with the solid rubber sleeves works better that the old style Lisle tool with the o-rings.This is what most shops use.The new Lisle tool has been updated to the solid sleeves style.

Lastly, always install the front bearing from the rear of the block.

Not just a problem with seasoned blocks, my new MP block had the same problem,
The very experienced machinist insisted I bring a used cam with, to check the fit when the new bearings were installed and it was too tight..
a few minutes with a machinists knife and all was good...

A friend found out the hard way that a too tight cam is not going to fly, after he broke the dowel pin in the cam shaft try to turn the motor over after his machine shop guy machined the block, and installed cam bearings..

Good luck trying to find oversized cam bearings, I bought the last set Dura-Bond had a few months back. If the bores aren't to far off you can use an old cam with spirl grooves cut into it and use it an a reamer. Now if the block has a lot of core shift you need to find someone around you with a Rottler F65 or 85 can't remember and have the shop bore the cam housing .010 over for the special bearings.

MLR426

I had to refresh this issue, I am currently building a 68 440 with this issue. Does anyone out there know a turning torque spec. for the camshaft alone. Mine is 15-20 inch pounds, seems a little tight to me.

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I had to refresh this issue, I am currently building a 68 440 with this issue. Does anyone out there know a turning torque spec. for the camshaft alone. Mine is 15-20 inch pounds, seems a little tight to me.

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Probally not a inch lb. spec. out there, if it feels to tight to you now get some scotchbrite and clearance it until you like the way the cam turns, unlike girls, a little loose is better than to tight