What would cause this??

[Rawze]

(11-27-2021 )JMBT Wrote:  Hello all, I have a 2012 Volvo with a CM2250, and 855k miles. I just popped the top to do an overhead. It has been about 95k since the last overhead I did. Everything up there is nice and clean. All of the cam lobes look beautiful, but on the first three sets of rocker followers, cylinders 1,2,&3 there are lines staring to form. The back three still look great. I cannot feel any of the lines with my fingernail so I don’t think they are very deep yet, but I was wondering what would have caused this? And how worried should I be??

Thanks in advance! JMBT

MORE causes of this, and/or overhead cam failures in general ...

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* LOWER THAN NORMAL OIL PRESSURES!. If the oil pressures are falling off due to excessive soot buildup in the enigne, or are lower than normal all the time...

- Anything less than about 28 psi or so oil pressures at idle is considered lower than normal oil pressures.

- If the oil pressure falls below about 33 psi or so while at speed (engine above 1300 rpm or so) is also considered lower then normal oil pressures.

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* USING SYNTHETIC OILS + extending oil changes + bypass filtration = A MAJOR contributor towards repeating overhead cam failures! .. and especially if your using synthetic oils and extending the oil change interval out more than 20k-miles+ on oil changes because your combining synthetetic and bypass oil filters. THE ISX DOES NOT LIKE SYNTHETIC AND EXTENDED OIL CHANGE INTERVALS!!. Everyone that I have met so far of that does this bulls$it to their ISX ends up replacing the overhead cams 2-3x more often that they should be.... and a lot of them are too god-damn stupid to realize that syn+extended oil changes is engine abuse!

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* THE CRANK CASE FILTER SYSTEM IS OFTEN THE PROBLEM. Any buildup of pressure.. even small amounts of pressures.. CAUSE THE OVERHEAD CAMS / valve train TO FAIL PREMATURELY! bacuase they are getting starved of what little oil pressure gets to them to begin with.

-- If the engine is getting old... THE paper-element style of crank case filter WILL NO LONGER KEEP UP with the amount of blo-by in the engine. ANY BUILDUP of crankcase fumes in the enigne IS REALLY BAD FOR THE OVERHEAD CAMS AND FOR THE TURBO!. i HAVE SEEN COUNTLESS ENGINES where that paper-style crank case filter was not keeping up on older engines.. Especially when often also combined with the truck owner not changing the filter often enough.. and it caused cam failures.. and the top-end to get starved of oil.

INSTALL A MAINTENANCE-FREE FILTER A.S.A.P! -- ref: http://rawze.com/forums/showthread.php?t...50#pid8950

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ANY RECENT CAM/VALVE train replacement work? .. If the valve rockers, cam(s)., etc. was replaced recently.. or the components were removed / re-installed. etc.. OR the head was replaced... Then a second adjustment is requires about 30-50k miles later to ensure everything has the proper clearances once everything has run a bit.

here is an older post that is related to this as well: http://rawze.com/forums/showthread.php?t...783#pid783