Open your hood and what do you see? If you’re like most car owners, the first
thing you see is not the gleaming marvel of mechanical engineering you saw in
the showroom all those years ago, but a greasy, dusty, filthy brown blob. You
don’t dare touch it lest its grime infect you.
The “blob effect” is normal and nothing to be ashamed of. The engine room is a
dirty place to live. It’s open to the elements and exposed to dust, moisture,
and fluid spills and sprays. It takes only a year or two of all-season driving
to turn even the most handsome new engine filthy.
What can be done about it? A coin-operated power wash is the easiest solution,
but not the best one. Spraying water into the engine compartment under the
high pressure found at typical coin-operated car washes can damage fragile
components, force water into electrical connectors, and even contaminate the
oil if it leaks past filler caps or dipsticks. If you want to hose down your
engine, spray a mild household degreaser such as Formula 409, let it sit for a
few minutes, set the nozzle on your garden hose to create a gentle mist, and
use that to wash off the cleaning fluid. Then run the engine so the heat
evaporates the water out of crevices where rust would otherwise form.
Still not happy with the way it looks? Here’s a job that will make your motor
sparkle, give you some peace of mind as to the engine’s condition, and provide
you with a fascinating glimpse into its inner workings. And it requires
relatively little time and money. Veteran shade-tree mechanics will have done
this job many times, but for novices, it can be a relatively risk-free and
rewarding way to get to know your motor and make it shine.
Cams, Rockers, and Rollers
Many new cars have a plastic cover on top of the engine. This cover blocks
sound and neatens up the engine compartment. If this applies to you, removing
the cam/rocker covers to shine them up may be pointless, as the acoustic cover
hides everything. If there is no acoustic cover, or you want to take off the
cam/rocker covers anyway, then read on.
On the very top of the cylinder head is a sort of oblong dome secured to the
cylinder head by a significant number of small bolts or screws. If your engine
is an inline-4 or inline-6, there will be one dome. If the engine is a
vee-configuration, such as a V-6 or V-8, there will be two of these domes, or
one capping each cylinder bank. This component can be made of stamped steel,
cast aluminum, or plastic, and it goes by many names: cam cover, rocker cover,
rocker-arm cover, rocker box, and valve cover. These names are often used
interchangeably, but each name actually refers to a specific engine type.
Example: “Cam covers” are found on overhead-cam engines, because the cover is
actually covering the cam shaft and its cam lobes. “Rocker arm cover” refers
to an overhead valve pushrod engine such as the new Chrysler Hemi or the
venerable Chevrolet small-block V-8. In these engines, the camshaft is deep in
the block but the rocker arms, set in motion by the pushrods, sit on top of
the cylinder head and lift the valves. From now on, we’ll refer to these domes
as cam/rocker covers.
The inside of a cam/rocker cover is a hot, oily place. As the engine runs, oil
is fed under pressure to the moving components to keep them lubricated, and
then slung by those components in every direction, draining back to the
engine’s oil sump via holes in the cylinder head. Some good reasons to remove
the cam/rocker cover, besides making it look pretty: if you have oil weeping
from the cover-to-head seal, or if you have just purchased the car and don’t
know its maintenance history.