AE 8.0 PRO 25480, User Manual

TUNING THE ENGINE FOR MAX POWER:

   Sometime between the fourth and the sixth tank of fuel, the inner engine parts should
be settled and broken in. You can then begin adjusting the fuel mixture to maximize
performance for your driving needs.
   As you continue to lean the fuel mixture, the engine will run faster up to a point. When
the engine is set too lean, it will seem to run strong at first, but will bog, hesitate, or stall
when running at high speed. The engine will also rapidly overheat when the setting is
too lean. This is because fuel includes lubrication, and that lubrication is inadequate
when the setting is too lean.
   CHECK THE ENGINE TEMPERATURE OFTEN AS YOU LEAN THE MIXTURE. DO NOT LET THE
ENGINE OVERHEAT. You should always see smoke coming from the exhaust.
   At the optimum setting, the engine will clean out; have a strong-sounding,
high-pitched whine at
full speed; and there will
be a thin trail of whitish
smoke coming
from the exhaust. It is
always better to set the
engine a little rich rather
than too lean.
   Find an area with a
long straight-away so
you can allow the engine
to run at full speed.  Run
your car two or three
at full throttle and note its

Read this before you drive

   The key to breaking in your engine is patience. During the break in period , your
engine may appear to malfunction with problems such as stalling, inconsistent
performance, and fouling out glow plugs. Don't give up. These are just a few things you
may go through during the break in period. Just keep it running, apply the throttle on
and off as smoothly as you can. Sudden bursts or quick releases of the throttle can stall
your engine. Soon after break in your patience will pay off with a well running engine.
   During break in, use the fuel with the same percentage of nitro which you plan to run
every day. The performance level of the engine will be limited by the "rich" fuel mixture
which you will use all during the break-in process. Once the engine is fully broken-in the
mixture can be "leaned out", and speed and acceleration will increase. Because of the
rich fuel mixture and the wearing of the new parts, deposits will form on the glow plug
causing it to fail. Expect to replace the glow plug during the break in period, and
definitely when the engine is fully broken in and the fuel mixture is leaned out. 

Understanding the engine terms “rich” and “lean”

Your carburetor has screws that regulate how much air and fuel enter the engine
together, the air/fuel mixture. A air/fuel mixture that is too "rich" means there is too much
fuel, and a mixture that is too "lean" means that there is not enough fuel for the given
amount of air. 
   When the mixture is too rich, performance will be sluggish (one symptom of this is
excessive amount of smoke from the exhaust). There is also a potential to foul the glow
plug when the mixture is too rich. 
   When the mixture is too lean, there is not enough fuel to cool or lubricate the internal
engine components, and damage to the engine and/or glow plug is almost certain.
   Turn the high-speed mixture screw clockwise to lean the mixture. This decreases fuel
flow for given amount of air. Turn counter clockwise to richen the mixture and increase
the amount of fuel to be mixed with the air.

Caution:

  If, while you are driving, the engine stalls because of an overheating

condition, severe damage may have already occurred. Overheating is caused by the
following conditions.
   Fuel mixture is set too lean.
   Air leak around carb.
   No air filter.
   Loss of muffler pressure (line falls off).
   Excessive nitro content in the fuel.
   Incorrect oil content in the fuel.
   Poor quality of fuel.
   Contaminated fuel.
   Excessive loads on the engine ( bound up drive train )
   Your engine will be short-lived if any of the above conditions are allowed to exist for
any length of time.

   During tanks one to four watch closely for any signs of overheating. These will include:
   Steam or smoke coming from the engine surfaces
   Cleaning out and then lagging during high-speed acceleration, as if it is running out
   of fuel.
   Popping or clattering sound when slowing down.
   Idle speed will surge or possibly diminish to the point of stalling.

To Test For Overheating:

   It's important to check the head temperature during the operation of the engine. The
best method for checking the head temperature is to use a head temperature gauge.
There are several head temperature gauges available, and the temperature readings
between these different brands of gauges vary. Due to this variance, the temperature
readings will range between approximately 220 degrees and 260 degrees. If you don't
have access to a head temperature gauge, you can use water to check the head 

Breaking in your engine for the first time

3

Tuning your engine's performance

4

Tanks 1-2 (Steps 1-3)

Tank 3 (Step 5)

Tank 4 (Step 5)

Optimum top speed setting

temperature. Place a drop of water on top of the cylinder head. If it sizzles away
immediately, shut down your engine. If it takes approximately 3-5 seconds for the water
drop to boil away, then the engine is running within a normal temperature range.

The First Two Tanks of Fuel

   Step 1

   The high-speed and low-speed mixture screws should already be set as they
were described to you earlier in this manual, Part 2, Step 2, "Setting the high-speed
mixture", and Part 2, Step 3, "Setting the low-speed".
   However, for break in procedures, the engine should run richer than these settings.
Turn the high-speed mixture screw counter-clockwise 1/4 turn from the position you set
it earlier to run it richer. (RTR GT truck engines come preset for standard setting.)

   Step 2

   Start your engine. Once the engine is started, ease in and out of the throttle slowly to
warm the engine. If the engine keeps stalling when
accelerating, then lean the high-speed mixture
screw a 1/8 of a turn counterclockwise. 
   The idle speed should be set as fast as possible
without causing the vehicle to move.  If necessary,
adjust the idle screw as described to you earlier in
Part 2, Step 5, "Setting the idle speed".

   Step 3

   The standard setting of the high-speed mixture
screw will vary slightly with each engine. To
know if your engine is set correctly you will find the
following performance characteristics (on a warmed
up engine): 
   The engine will accelerate sluggishly from a
standing start and may even try to quit if the throttle
is applied too quickly.
   Blue-white smoke will be coming from the exhaust. 
   When the car is accelerating at full throttle, the
engine will never "Clean Out". When an engine cleans
out, the speed and the rpms will increase suddenly
and dramatically, as if the engine has switch to
second gear. Also, the amount of smoke that comes
from the exhaust will decrease. Cleaning Out is a
desirable characteristic once the engine is fully broken
in.
   As the engine reaches normal operating
temperature, it will speed up and performance will
increase. This occurs because the fuel mixture is
becoming leaner with the increased temperature. You
will need to richen the fuel mixture about 1/16 of a turn
or more so that the engine continues to run as
described above.

   Step 4

   When the first tank is almost gone, bring the car in
and shut off the engine.  Allow the engine to cool for
8 to 10 minutes before starting the engine up again.
Add more fuel. Start it back up and run the second tank
of fuel. Again allow the engine to cool before starting it up again.

Tanks Three – Four

   Step 5

   Turn the high-speed mixture screw clockwise (leaner) 1/8 of a turn and run it
through the third tank of fuel. Repeat this step for the fourth tank of fuel. This completes
the engine break-in procedure. Now go on to Part 4, Tuning.

open

1/4 turn

1/8 turn

1/8 turn

standard setting

(3 turns)

standard setting

high-speed mixture screw slot shown

your optimum top speed setting

will be in this area, which differs

from engine to engine.

optimum needle

valve setting

standard

setting

DANGER!

maximum lean setting

(overheating likely)

performance. Turn the high-speed mixture screw clockwise 1/8 of a turn and retest your
car, again noting the vehicleís performance. Continue to lean the mixture and retest
the vehicle until the best performance is achieved. At that point, turn the mixture screw
counterclockwise 1/16 of a turn. This is the optimum setting that the engine should be
set to run at.
   If the engine stalls on acceleration, begins to bog or slow down at full throttle, or if
there is a reduction in exhaust smoke, then the engine is running too lean. Immediately
turn the high speed mixture screw counterclockwise 1/4 of a turn and operate the car at
medium speeds for 1 to 2 minutes to allow the engine to cool. Then, continue testing.

TUNING FOR LOW-SPEED PERFORMANCE

   The low-speed mixture affects how the engine will perform in the low to mid range
rpms. Turning the low-speed needle clockwise will lean the mixture. As with the high-
speed mixture, leaning the low-speed mixture increases performance. Again, if the
mixture here is set too lean, the engine may be starved for lubrication in the low and
mid-rpm ranges, thus causing overheating and excessive engine wear.
   Perform the following test to determine if the low speed mixture is set correctly. 
   With the engine warm and running, allow it to idle for approximately 15 seconds. Now
quickly apply throttle and note the performance. 
   If the engine bogs, accelerates erratically, and a large puff of blue smokes emitted,
then the low speed mixture is too rich. Turn the low-speed screw clockwise 1/8 of a turn. 
   If the engine speeds up for a moment then bogs, hesitates, or stalls, then the low
speed mixture is too lean. Turn the screw counterclockwise 1/8 of a turn. Adjust the
mixture screws in 1/8 of a turn increments, wait 15 seconds, and retest after each
change. Adjust for the best acceleration without the car stalling.

2