two valvetrain questions

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Hi all

couple of questions that had been troubling me:

1. How the hell do the 3 nuts on the intake washers actually stay tight and don't just loosen and fall off with all the valvetrain vibrations and motions? They are only tightened to 10Nm ! (#12 here: http://www.realoem.com/bmw/showparts...37&hg=11&fg=25)

should i have gotten new nuts for this? or old ones are fine?
same question goes for the intake studs

2. I understand the intake sprocket is designed to move around, but how the hell do the exhaust sprockets stay in particular phase (angular position relative to the exh cam angular position) if they are only held by the smooth surfaces of the cam and the big washer. I'd imagine oil would have no problem getting between the washer and sprocket surface and make it easy to move around.


Big thanks
Alex

[hoveringuy]

I just got done reassembling mine and ended up replacing the intake nuts and studs because of some galling on one stud. I would have re-used them otherwise. I used blue loctite and 10Nm to keep it safe. Vibration is really only a problem when it overcomes the tension on the nut.

The intake sprocket doesn't really move, it's the cam that moves relative to the sprocket and the helical gear on the VANOS controls the phase shift when it moves in and out. The large intake washers provide friction that the VANOS moves the cam against. The intake cam is supposed to move within that washer when the VANOS cycles.

The exhaust cam is bolted tight to the sprocket and only moves with the crankshaft.

Oh yeah, I'm picking up the crane today and the old engine starts coming out Thursday.

"watch this space"...

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btw, for those who are interested, here is what bf.c members have to say to these questions:

http://forums.bimmerforums.com/forum/showthread.php?p=12234983&posted=1#post12234983