Originally Posted by
sharp1017
I am in the process of rebuilding the top end of the M52 engine in my 1996 328i to fix a leaking head gasket problem.
I took the head off and sent it to a reputable shop in town to have it rebuilt and tested. They leveled the deck, replaced the valve guides, ground the valves and seats, pressure tested it, etc.
I removed the cams, lifters and trays before taking the head to be rebuilt and, unfortunately, I neglected to label the position of each lifter. So, when I reinstalled the cams, lifters and trays, there was no way to know which lifters went were. I realize that they are all the same part, but several posts I have read stated it is always better to put them back where they came from when possible. I will know better next time.
Onto the problem I need help with - Now that they cams and lifters are installed (using a good amount of assembly lube), I have turned the cams several times (using a 24mm wrench on the center of the cam) to ensure they are moving freely and that the valves are all opening and closing as they should. However, when I do this I notice a couple of the valves are not closing all the way when the cam lobes are up (see attached images). I also notice the some of those valves are opened a different amount (from the valve next it) when the cam lobes are down. I have taken the cams back out and checked the lifters and everything appears to be fine. I even rebuilt a couple of the lifters to ensure nothing was stuck inside them.
I also confirmed that the valves are closing all the way when I removed the cams to check the lifters, so I am pretty sure it is not a problems with the valves, guides, seats or springs.
So, is this normal behavior for cold lifters in a newly rebuilt head?
Will they settle in once the engine starts?
Is there a risk of the valves striking the top of the pistons if they don't settle in fast enough?
Sorry if these are lame questions, but this is my first time rebuilding the top end on a BMW and I really don't want to damage the engine after spending all of this time and money.
BTW, I was very careful using the "only cylinder 1 open" method for removing and reinstalling the cams, so I don't think there is any damage to the cams.
Thanks in advance for any help/advice.
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BTW, I pointed a light source into the port behind the problematic valves to better illustrate the problem openings. That is why there is a halo of light in the "almost closed" pictures.
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