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If a generation is roughly 25 years, I calculate
that our sport is about to see its third generation of
racers pull into the staging lanes. As NHRA celebrates
its Golden Anniversary season, I'm grateful for the
improvements in the quality of parts that the first two
generations of racers have produced.
When I started racing years ago on dusty
Southwestern drag strips, we expected to break parts. My
friends didn't ask me on Monday morning, "Did you
win?" Rather, they wanted to know, "What did
you break?" The station wagon rearends, junkyard
4-speeds and oddball parts that were the staples of our
so-called racing program were the strongest pieces we
could pull out Texas salvage yards - but they still
couldn't withstand the unreasonable demands of a bunch
of neophyte drag racers.
Today's drivetrain and engine components are
stronger, more reliable and better engineered in every
way. Advances in metallurgy have produced valve springs
that can endure maximum lifts that were simply
unimaginable a few years ago. Aftermarket axles can
stand up to hundreds of full-throttle launches without
flinching. Best of all, access to these pieces is as
easy as picking up a telephone. I don't miss the days of
sorting through piles of grimy cylinder heads to find a
pair of usable castings.
Statistically speaking, there has never been a
better time to be a drag racer. But the problem with
statistics is that they are averages. We know, for
example, that your chances of being hit by a meteorite
are miniscule - but that's little consolation if you're
standing in the wrong spot when one lands.
It's the same with racing engines. I've seen
engines make 600 passes without a problem - and I've
seen motors that self-destructed after only 30 runs. You
might conclude from these statistics that the average
life expectancy of a racing engine is 315 runs, but that
certainly doesn't reflect the reality of the situation.
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You must be able to distinguish between types of
failures. If an airplane is delayed while the mechanics
repair a problem on the ramp, that's just unscheduled
maintenance. If an engine fails in flight, that's a
serious problem. The situation is the same with a racing
engine: If your motor breaks a rod, that's a
catastrophic failure. When you perform an autopsy and
find that the bearing didn't spin and the engine didn't
have an oiling problem, then all you can say is that the
rod failed prematurely. It was the exception that
lowered the statistical average.
As the quality and longevity of parts have
improved, there is a natural tendency for racers to
become complacent. It's rare these days to see a broken
valve spring when you pull off the valve covers. But it
is still vitally important that you look, instead of
just assuming that the valvetrain is OK. Personally, I'm
delighted when I remove a valve cover and find
everything in perfect working order.
I recognize that when you are running round-robin
in eliminations that you can't look at the valve springs
after every run. But you can check them, along with the
oil filter and a magnetic oil pan plug, at regular
intervals when you're not racing on the track.
The most important preventive maintenance you can
perform is to check the valve lash. A common problem I
see in bracket engines these days is broken roller
lifters. Not instant destruction caused by valve float,
but wear and fatigue that gradually grind down the
needle rollers inside the lifter wheel. As these highly
loaded needle bearings start to break up, the valve lash
increases dramatically.
If you check the valve lash religiously, you can
spot these problems before they cause further damage.
But if lifter problems aren't detected early, the
needles will be pulverized and the roller wheel will
recede into the lifter body. When that happens, the
lifter body grinds into the camshaft lobe and you get
metal filings everywhere - on the cylinder walls, in the
piston skirts and in the bearings.
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