In the last two months, I have discovered a new kind of
power: the power of the press. I've worked with mills,
lathes, and hones for thirty years, so it was a real
challenge for me to sit down at a word processor and
begin my second career as a writer. I genuinely
appreciate the comments and compliments I have received
since I joined the ranks of National DRAGSTER's
back-page columnists.
My sense of humor is no match for Bob Frey's, and I
can't offer any insights into the human condition like
Rev. Owen and Dr. Torstveit. I do know a little about
building engines, however, and that is going to be my
subject. I promise that I won't deluge you with theory
and analysis; my intention is to offer practical advice
and real-world recommendations based on my own
experience.
I don't make
any claim that my word is gospel - I'll leave that to
the good reverend. Other engine builders may not agree
with my opinions about particular parts and procedures,
but I know what works for us at Reher-Morrison Racing
Engines.
I always advise racers to consider the long-term costs
and consequences when they are buying engine components.
Parts that are initially inexpensive can be very costly
to maintain over
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the course of a season. For example, a
flat tappet camshaft is much cheaper than a roller cam
and lifters - but in the long run, a flat tappet cam can
be a black hole that sucks up dollars.
Flat tappets
may be fine for street engines, but I don't recommend
them for any serious racing application. Sure, NASCAR
Winston Cup engines have flat tappets, but that is
because the rulebook requires them. We have built
several NASCAR motors, and the extra work it takes to
make flat tappets live in a racing environment is a real
pain. The tappets must be precisely positioned on the
tapered cam lobes in order to make the lifters rotate.
If the tappets don't spin properly, they will wear the
lobes flat almost instantly. A flat tappet cam must be
broken in with light-tension springs, which involves the
extra expense and effort of switching to heavy springs
after the break-in period. Finally, there is an absolute
limit to how much spring pressure a flat tappet can
withstand before it galls the camshaft and turns itself
blue.
The odds are against any production block having every
lifter bore in the right position and at the correct
angle. NASCAR engine builders use elaborate fixtures to
machine the lifter bores perpendicular to the camshaft
centerline and to position the lifters accurately on the
lobes. Many
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