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Winter Break-in Tips
During the break-in process, the piston and sleeve wear into each other
to form a precise fit. The engine needs to heat up to a temperature
around 200 to 215 degrees to allow the piston and sleeve to achieve
this fit properly. A precise fit between these two components is critical
for proper compression, and optimum performance. If the engine runs
too cold during break-in, the piston and sleeve will not expand to their
appropriate sizes for break-in, and this can lead to premature wear of
these components. This wear may not become apparent until after
winter has past, and the engine is operated under warmer running
conditions.
Warm the engine to approximately room temperature by removing
all fuel and storing the vehicle inside at room temperature until just
before starting the engine. An extremely cold engine can become
difficult to start.
After the engine is running, it is important to keep the temperature
of the engine up around 200 to 215 degrees during break-in. In
weather below 45 degrees, the TRX 3.3 Racing Engine will tend to
run at lower temperatures between 160 to 180 degrees (when tuned
at proper break-in mixture settings). This is too cool for break-in.
Do
not lean the fuel mixture to increase engine temperature!
This
will also decrease lubrication and cause your piston/sleeve to wear
prematurely.
Wrap the cooling head with a paper towel,
clean rag or sock to help keep the engine
running around the recommended 200
to 215 break-in temp. If too much heat
is contained, the engine can actually run
too hot. Make sure that you monitor the
engine’s temp closely for the first couple
of tanks until you get the right amount of cover for the cooling head.
This will, of course, depend on your current weather conditions.
Adjusting the cover up and down, exposing more or fewer cooling
fins, is a convenient way to regulate engine temps.
For owners that do not have access to a temperature probe, a drop of
water on the cooling head (around the glow plug area) should slowly
sizzle for approximately 6 to 8 seconds around 200 to 210 degrees. If
the water sizzles for only a few seconds, then it is likely that it is over
220 degrees, and needs to cool down. If the water takes a long time
or does not evaporate at all, then the engine is too cool.
We do not recommend that you operate your engine below 35
degrees Fahrenheit. If you insist on running your vehicle below 35
degrees, be aware that nitro engines may be very difficult to start
and tune at extremely cold temperatures. Also, at temperatures
below freezing, nitro fuel can actually begin to gel up, and this can be
harmful to the engine.
Follow the remaining break-in procedures as outlined in this Owners
Manual. This, along with the steps listed above, will ensure a good break-
in for your new nitro engine, and provide many hours of enjoyment.
TUnInG YoUR TRX 3.3 RAcInG EnGInE
The engine’s performance
depends on the fuel
mixture. Turn the mixture
needles clockwise to
lean the fuel mixture and
counterclockwise to richen
it. Leaning the fuel mixture
will increase engine
power up to the engine’s
mechanical limits.
Never
run the engine too lean
(not enough fuel flow).
Never lean the engine
until it begins to cut-
out or stall.
Leaning the
engine beyond the safe
allowable limits will result
in poor performance and
almost certain engine
damage.
Indications of an overly lean mixture include:
Cutting out or sudden loss of power during acceleration.
Overheating (temperature beyond 270° F at the glow plug).
Little or no blue smoke coming from the exhaust.
If any of these conditions are present, stop immediately and richen
the high speed mixture 1/4 turn. The engine will probably be slightly
rich at that setting and you can then retune for performance. Always
tune for performance by starting rich and moving leaner toward the
ideal setting. Never try to tune from the lean side. There should always
be a light stream of blue smoke coming from the exhaust.
When tuning for
performance, watch closely
to notice when there is no
longer any increase in speed
or power when the
high-speed mixture is lean.
If you lean the high-speed
mixture to the point that the
engine cuts-out, hesitates,
or stalls, you are well into
the danger zone and engine
damage is likely. Richen the
high-speed needle 1/4 turn
and retune.
For your convenience, the
low-speed needle has a
positive stop that prevents
it from being over tightened
and damaging the needle
and seat. This also provides
an easy way to gauge how
many turns out from closed
the low-speed needle
adjustment is set to.
The TRX 3.3 Racing Engine
