M3 over rev protection...

[RFKoby@xxxxxxx]

Brian ?? from PTG said at Gateway last spring...
that you could shim the underside of the valve springs 0.020"???
this would prevent the valves from overtraveling during high rpm (over rev)
valve float....
The hydraulic lifter response / harmonics cannot keep up over 7,000+ rpm...
The lifters and springs simiply cannot react far enough, thus
they have a trendency to overextend the valve, and the piston will contact the
valve.
By shimming....
you prevent the overtravel mechanically,
the the hydraulic lifter takes the brunt of the cam during one revolution
instead of overextending the valve....

this is only my intrepretation of his talk on the subject....

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