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      01-16-2021, 06:01 PM   #1
ClampThurst
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X3 F25 camshaft pattern

Replaced the valve cover gasket on my 2017 X3 3.5i and saw this pattern on the cam lobe. Wondering if this is normal or sight of abnormal wear.
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      01-17-2021, 09:33 AM   #2
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Looks unusual; have you had any issues in past with how the motor runs? (valve clatter, misfiring, etc.)

How many miles on the car?

See pic, unfortunately camera not focused properly but as I recall the lobes on my car's camshaft (this is actual pic at 85K miles, N52 motor) were very smooth; certainly noting like what's shown in your pic.
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Last edited by Wgosma; 01-17-2021 at 12:08 PM.. Reason: add pic
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      01-17-2021, 11:31 AM   #3
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I replaced my valve cover last year and didn't notice those lines. Wear lines would obviously run parallel to the lobe. They look like original machining marks but I would think they would be polished by now. Can't help. Sorry
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      01-17-2021, 12:01 PM   #4
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I've seen a lot of cams but have never seen one with those patterns. Is every single lobe like that? Can you feel them with your fingernail. Really strange
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      01-17-2021, 01:58 PM   #5
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Quote:
Originally Posted by pungo View Post
I've seen a lot of cams but have never seen one with those patterns. Is every single lobe like that? Can you feel them with your fingernail. Really strange
Every single on was like that. The feel of the lobes is absolutely smooth. The engine runs great and has 62k miles on it. Will be doing an oil analysis ASAP to see if there is metal in the oil.
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      01-17-2021, 02:06 PM   #6
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I doubt anything in valve train caused that pattern. I'd think the cam spins way to fast for something to cause it. Maybe it's a newer machining method from the factory to improve oil lubrication
This is a new one for me and I'm curious to know the answer.
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      01-17-2021, 02:09 PM   #7
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Upon further analysis, this might just be the original forging lines of the metal. The pattern continues even on the edges of the lobes, the part not in contact with the lifter arm.
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      01-18-2021, 12:01 PM   #8
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Looks like forging striations to me. Shouldn't have them but I don't believe you are going to see longitudinal stress that would cause the camshaft to "lengthen" and separate. We need a metalurgist to comment to be certain but I doubt an issue.
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      01-18-2021, 12:41 PM   #9
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nope, looks fine
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      01-23-2021, 04:09 PM   #10
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I just saw the same pattern on another N55 engine valve cover gasket DIY on this forum. Must be normal for this cam.
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      01-23-2021, 05:00 PM   #11
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I am not an engineer!

Looking at it it would seem that the pattern, although smooth to the touch, is? ground that way to serve as micro oil galleys?
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