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Discussion Starter · #1 ·
Okay so here's the back story. I have an 08 6.4, with 137k miles. KEM tuned, all deletes, and some other goods. So a while back I was starting to hear a thumping sound, sounded like it was coming through the intake. After further reasearch I was pretty well determined on it being a rocker arm. And when I take my oil cap off there's a ton of blow bye, plus a little tinging type sound on the passenger side valve cover area. So basically I bought all new rocker assembly, pulled the passenger side valve cover off, and inspect the rockers. None of them are broken, and I can't tell if the tips are warn because I haven't fully taken them off. But about 3 of them will move side to side a lot. None of the clips are broken off, but they have a lot of play. Is that normal? They will tilt left to right about an inch both ways. So have I found my problem? What makes me think this is wrong is because other rocker arms won't move at all, but idk if that's because there normal, or cause they're pushing on the valve springs hard enough to make them snug.. Any thoughts?
 

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i believe blowbly is not caused by faulty valvetrain, it is caused by issues with piston, piston rings, cylider wall, leaking and compression from combustion going into crankcase. perhaps a manual compression is a good idea. the movement of the rockers from side to side is somewhat normal and like you said the the cam is pushing them open you will not be able to move them, you can ussualy tell if the pivots of the arms (that contact the bridges) is worn if you compare then with a new unit. they should not be flush the the arm they should "stick out" around 1/8". Makes sense?
 

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Discussion Starter · #3 ·
So I replaced my rockers. And I ended up having a broken push rod, on the #8 cylinder exh rocker. This would cause the exhaust valve to not open an exhaust would go through my intake valve causing what I thought to be blow bye. As it's all replaced and put together now it runs great and has normal blow by for a 6.4. Also the new rockers did move side to side like you said they should but definantly not as much as the old ones. Thanks for the help!
 
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