Quote:
Originally Posted by OldMercs
Has anyone ever experienced failure of the sodium-filled valves on an M117 in a high-ouput or high-mileage situation? I've read about non-Mercedes cases where an engine builder will discard sodium-filled valves in a souped up engine claiming that they become a weak link in such an application.
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I would guess two things:
1) When building a race motor you want the lightest valves possible to avoid high RPM float or excessive spring pressure. Sodium filled valves hava a larger diameter stem, more than likely increasing the total weight.
2) When building a race motor you want the least amount of obsticals in the way of airflow in the intake system. It is not uncommon to neck down stems in race motors. The larger diameter stem of the sodium filled valve is an obstruction to airflow.
John Roncallo