Hey all.
Recently a poster with a Federal 1500 Spit mentioned that his max
revs seemed to be around 4000, and wondered why.
My 1500 misbehaves around 4100, producing a sort of vicious buzz,
which goes away again at about 4200 or 4300, and is fine after that
up to the red line.
What occurs to me is that the US 1500 had single, rather than double
valve springs. Makes for freer revving but my reading tells me that
this can result in the engine being vulnerable to bad vibrations when
you hit the natural harmonic frequency of the spring. Do I have this
right? Any engine-eers have some enlightening thoughts on this
subject?
Dan Parslow
'65 Vitesse, '79 Spitwad^H^H^Hfire
djp@alpha.sunquest.com
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