Cam Lobe Centers and Caps

[JHertzman@xxxxxxx]

In AD7-250 Bob Brady asks a bunch of questions about cams, caps, and scribe
marks.

My understanding has been that the great blessing of having two cams with
vernier adjustment of the drive gears is that the factory (initially) or the
knowledgable modifier (later) could play games with both the overlap and the
timing in order to make trade-offs among smooth low end, gutsy midrange,
maximum top end, even fuel economy and emissions, while using the same cams
for intake and exhaust. On his question about the common-sense of scribing the
caps versus the cams, one is steel, the other is relatively maleable aluminum
on which old scribes can be erased and new scribes scribed. If servicing an
existing engine, same caps, same cams, you just toe the mark. If changing cams
(or finessing the timing of the existing cams) you use a degree wheel (or
degree-index the crank pulley, Kartalamakis p.37) or do things some harder
way, and remark the caps when everything is spot-on.

If the intake and exhaust cams aren't interchangable - - I need some new parts
books.

John H.

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End of alfa-digest V7 #251
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