Magnum camshaft bearing mystery

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737jetdr

737jetdr

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I have 2 360 magnum motors that I purchased used. Both have over 100k on them. Both were exceptionally clean inside. No sludge, cylinder wear at a minimum, etc. When I went to change the camshaft, Both had weird wear and damage on the #4 cam bearing " see pics"
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No damage found on either camshaft. Just curious if anyone else has noticed something similar and maybe an explanation.
 
I just pulled my 5.9 apart. I didn't notice cam bearing damage but I'll take another look.
 
Maybe from when the cam went in at the plant. There is nothing significant about it being a magnum engine, they all can do this or be assembled in such a rough way that bearings are damaged.
I pulled a 360 down I rebuilt over 10 years ago. I was gentle..didn't bang the cam around..but no.2 cam bearing started coming apart at the edge and working it's way toward the oil hole. Just change the one or all if you have the ability. I just changed 1,2 . 1 to get to 2 in other words.
Who knows.
 
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Yep, magnums eat cam bearings. It doesn't seem to cause a problem as they will go 300k miles and run great, but when you see it, you replace it. Strangely, it can be only 1 and the rest will look fine.
 
That's the case. Only 1 is bad. I just thought it was odd that both motors had the same bearing go bad. It looks terrible. I am changing the cam anyways but I was expecting to see damage to the cam but found nothing. I'm going to replace them for sure. This was more for my own curiosity .
 
737jetdr said:
That's the case. Only 1 is bad. I just thought it was odd that both motors had the same bearing go bad. It looks terrible. I am changing the cam anyways but I was expecting to see damage to the cam but found nothing. I'm going to replace them for sure. This was more for my own curiosity .
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Could have been a bad run of bearings , high spots. Usually when I see an oiling issue the bearing changes color as well, darker color.
The cam bearing is ultimately fed from the intersection of the main saddle from the oil feed coming from the lifter galley.
So if you had a main bearing to look at from no. 4 and see how the hole lines up, if theres a feed issue
 
737jetdr said:
Hole was lined up on both motors. Maybe just a assembly snafu at the factory.
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It's very common on the magnums. My '01 Ram has 303,500 miles on it. Runs great, but I am sure the heads would be cracked and at least one cam bearing would be ate up. Again, runs great and is my daily driver (over 50 miles a day)
 
one of the last bearings to get oil on start up / the oil has a hard time making a 90 deg turn and must go to the end of the main gallery pressure builds then backfills the main bearing then up to cam. and that's my guess for today.
 
Have seen that before.

Getting new bearings and cam, so you just put in all new anyway.

There are acids in oil that can eat away at the bearings. Even though everything looks good, it's the 50 years of time and the oil breaking down from sitting that is hard on the bearings.

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Quite common, have seen it on many engine brands. Bearing surface de-laminating.
 
737jetdr said:
I have 2 360 magnum motors that I purchased used. Both have over 100k on them. Both were exceptionally clean inside. No sludge, cylinder wear at a minimum, etc. When I went to change the camshaft, Both had weird wear and damage on the #4 cam bearing " see pics"

View attachment 1715928665 View attachment 1715928666 No damage found on either camshaft. Just curious if anyone else has noticed something similar and maybe an explanation.
Click to expand...
I just rebiult a 5.9 magnum same thing #4 cam bearing was bad.
 
Have fun installing cam bearings. Look up tight cam fitment here.
 
Every Magnum I’ve torn down, the cam bearings look like that!!!

I inspected the cams and found no scarring or damage to them!

It’s a Magnum mystery for sure!!!
 
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