Page 72 - Issue 37

The oil you choose plays a big role in engine performance.

BY JOHN BAKER, TECHNICAL WRITER – AMSOIL INC.

hen building or working on allowing the engine to burn more fuel and
your rat rod, motor oil is easy to make more power. A performance cam
overlook. Pouring a few quarts operates on the same principle, allowing
of liquid gold into your fi ller more air/fuel to charge the combustion
W port doesn’t provide near the chamber. The list of modifi cations goes
satisfaction as fi nding that long-sought-after on, and most of them result in the engine
part or bolting new headers on your engine. producing substantially more heat than a
However, since motor oil is the only thing stock engine.
that prevents your expensive engine from One of motor oil’s main functions is to
blowing up, it pays to know a few basics. carry this heat away from engine parts and
To illustrate, let’s take a closer look at a dump it into the atmosphere via the oil
couple challenges the typical rat rod motor pan or oil cooler. Extreme heat, however,
presents and how motor oil helps solve them. can cause oil to chemically break down
(oxidize), particularly conventional oils. As
it breaks down, the oil’s chemistry changes.
It becomes thicker, for one. Thicker oil is
more diffi cult to pump through the engine,
reducing fuel effi ciency. Oil that is too thick
to pass through narrow oil passages can
starve the engine of oil, especially the upper
end. You don’t need an engineering degree
to know what happens to an engine that’s
starved of oil.
Oil that breaks down also can lead to
formation of performance-robbing deposits
throughout the engine. Carbon buildup on
the piston crown can lead to preignition,
while buildup on the rings can cause them
to stick, which reduces compression and
can lead to power loss. Dirty engines are
Increased Heat simply less effi cient and more prone to
The modifi ed engines that dominate mechanical problems.
rodder culture deliver the added power and
torque you crave, but also create extreme Extreme Pressures
heat that can lead to reduced performance Modifi ed engines also create increased
if your oil isn’t up to the challenge. Turbos pressures and shearing forces. When
jam more air into the combustion chamber, oil passes between engine parts, the

72 RAT ROD MAGAZINE ISSUE THIRTY-SEVEN

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