Engine experts, including those at McDonnell Douglas and the Society
of Automotive Engineers (SAE), have demonstrated through several
studies that the majority of mechanical wear (up to 90%) occurs during
engine start up. Experts believe one start is equivalent to 500 miles
of normal driving. Regular oil changes and preventative maintenance
help to reduce wear, but there is one problem that always causes
headaches-dry starting.
Dry starting refers to the gap between an engine start and the
introduction of oil and oil pressure into the engine. Engine parts are
most vulnerable to dry starting when the engine has been inactive
through a weekend, between trips, or even overnight. The abrasive
metal particles that rub off during a dry start accelerate engine
wear. Engine parts strained and most affected by this condition
include bearings, turbo bearings, rods, pistons, and heads. The turbo,
which is the last critical part of an engine to receive oil from the
oil pump, is also at risk.
And how does lack of oil pressure affect engine wear? You wouldn't
dream of driving your bus without oil pressure. In fact, if pressure
drops, you know what the consequences could be. So why then, do we
start our engines without it?
Many drivers believe that etting an engine warm up at a slow idle
will solve the problem. But the only way to eliminate dry start wear
is to achieve oil pressure and lubrication before start up. Solutions
have included pulling distributors and hooking a drill up to the
mechanical oil pump to lube engines before startup and turning engines
over until the oil "idiot light" goes off. This would be a
good idea for all of us, but it isn't very practical.
Now, it is possible to pre-lubricate and pre-pressurize your engine
before starting with a patented pump and motor assembly, called the
Pre-Luber. Marketed to the automotive industry since 1986, the Pre-Luber
pumps oil from the oil pan into the sending unit, or a main oil
galley, prior to engine start. It achieves up to 55 pounds of
pressure, depending on the size of the engine, and bathes the engine
in oil to prevent drystarts, oil starvation, and destructive
metal-to-metal contact before oil pressure is achieved.
Not only does the Pre-Luber automatically prime and pressurize the
engine before starting, it continues to run after the engine is shut
down, cooling off critical engine parts and turbo bearings in order to
prevent "coking." In addition, the preluber saves on idling
the engine and the fuel costs associated with idling. Turn the key off
and the Pre-Luber activates an adjustable cool down cycle. Independent
tests show that the application of Pre-Luber to an engine
significantly reduces friction during engine start up and reduces
bearing wear by as much as 53%. This doubles your engine life.
Opening a door or (more commonly) turning the key to the
"on" or "accessory" position activates the Pre-Luber,
which starts a 60 second pre-lubrication cycle. Immediately, the
friction prone surfaces throughout the engine are coated in oil: the
rods, main cam, turbo bearings, chains, etc. A small, electronically
controlled module automates the functions via a signal from the
ignition sensing wire. There are no switches or buttons on the dash or
control panel to worry about.
The post-use or "cool-down" cycle is advantageous for
buses with a turbo. Turbo bearings remain extremely hot after engine
shut off, which creates oil "coking." Many manufactures
recommend idling the engine to cool it. The turbo version of the Pre-Luber
provides as much as a five minute "cool-down" cycle and
continually circulates oil through the engine and turbo, thereby
preventing coking, eliminating the need for idling and fuel use, and
reducing condensation and water content in the oil.
Another advantage of the Pre-Luber is the simple and easy oil
change. The hose connected to the pump outlet can be fitted with a
quick disconnect coupling, allowing that hose to run to a container
where the oil can be eliminated from the oil pan. Turn the key to the
"accessory" position and pump the oil. Most oil can be
discarded in about two minutes.
Installation is simple, so no special hand tools are required. The
Pre-Luber is sold as a turn key kit and includes the pump and motor
assembly, necessary fittings, mounting screws, the control module, and
wire harness, Most owners prefer their own hoses. Your mechanic can
normally install a Pre-Luber in about two hours.
For more information, call 800-836-8601.
... from BUS
WORLD, July 1999, p. 36, 37.
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