THUNDER TIGER EK4-S2 User manual

Thunder Tiger Corporation guarantees this model kit to be free from defects in both material and workmanship.
The total monetary value under warranty will in no case exceed the cost of the original kit purchased. This warranty
does not cover any components damaged by use or modification. Part or parts missing from this kit must be
reported within 60 days of purchase. No part or parts will be sent under warranty without proof of purchase.
To receive part or parts under warranty, the service center must receive a proof of purchase and/or the defective
part or parts. Should you find a defective or missing part, contact the authorized Thunder Tiger Service/Distributor
nearest you. Under no circumstances can a dealer or distributor accept return of a kit if assembly has started.
JD1440.V3
No.6216
1/8 OFF-ROAD, 4WD MONSTER TRUCK

1
2
a. Take out the 4 screws on the chassis securing the plastic servo tray.
b. Install the servos with tap screws. Notice the orientation of the steering and throttle servo output shafts.
c. Install the receiver switch onto the rear of the receiver box with its original screws.
d. Properly plug the connectors/wires into the receiver: steering servo connector/wire into channel 1 slot, throttle servo
connector/wire into channel 2 slot, and battery switch connector/wire into battery slot.
e. Remove the receiver box top's 4 screws and place the receiver and the wires inside the receiver box, thread the receiver
antenna/wire through the box top hole, and reinstall the box top.
f. Thread the receiver antenna/wire through the antenna tube, then install the antenna tube onto the box top hole.
g. Install 4 AA size alkaline batteries in receiver battery box and strap the battery box onto the battery plate with two large
nylon zip-ties.
h. Connect the receiver battery box wire/connector to the receiver switch wire/connector.
i. Install the battery box & plate onto the posts, then use the large body clips to secure the plate onto posts.
a. Build the steering linkage as shown on the diagram .
b. Install the servo horn onto steering servo output shaft with its original screw.
c. Pop the tie-end onto the standoff ball on the steering rack.
INSTALLING THE RADIO GEAR
INSTALLING STEERING SERVO LINKAGE
2
ac
f
b
e
d
i
h
g
abc

3
3
a.Build the throttle/brake linkages as shown on the diagram.
b.The throttle/brake linkage should appear as shown.
c.Install the servo horn onto throttle sero output shaft.
INSTALLING THROTTLE LINKAGE
a. Plug the charger into an AC outlet.
b. Line up the charging adapter with the tip of the glow plug igniter.
c. Pull on the glow plug igniter lever to accept the charging adapter.
d. Plug the charging adapter into the glow plug igniter. At this point, the small red LED indicator on the
charger should light up indicating the charging sequence is in progress.
e. Unplug the glow plug igniter from charger after charging is complete. Pull on the glow plug igniter
lever.
f. Pull the charging adapter out of the glow plug igniter.
Charge the new glow plug igniter for 16 to 24 hours on the first charge. For subsequent charges, charge
it about 12 hours before next use.
NOTE:
If the igniter gets warm or hot during the charge, unplug the igniter from charger immediately. A warm /
hot igniter means the igniter is overcharged. Overcharging can damage the internal battery in the igniter;
thus, shortening its life.
CHARGING THE GLOW PLUG IGNITER
4ab c
fe
d
c
b
a
Thunder Tiger Optional Part #2165, 1300MAH Glow Starter w/220V Charger.
Thunder Tiger Optional Part #2166, 1300MAH Glow Starter w/110V Charger.
To brake cam
To engine
carburetor
lever

5
a.Check the frequency printed on the transmitter crystal.
b. Check the frequency printed on the receiver crystal, and make sure it matches with the transmitter
crystal. Make sure no one will operate on the same frequency when you are. When there is a radio
glitch, it will most likely be caused by improper crystal, damaged crystal, or people operating on the
same frequency.
c.Install the antenna into transmitter.
PREPARING THE RADIO
6
a.Install 8 AA-size alkaline batteries into transmitter.
b. Undo the large zip-tie, and remove the receiver battery box. Install 4 AA-size alkaline batteries into
receiver battery box.
c.Secure the receiver battery box with batteries back onto the posts with large body clips.
RADIO BATTERY INSTALLATION
abc
4
a. When turning radio on, first turn on the transmitter.
b.Then, turn on the receiver. When turning off, first turn the receiver off, then the transmitter off.
c. To reverse the functions of servos, use the small, white servo reverse switches located on top of the
pistol transmitter (or the inset servo reverse switches located at the center of the stick transmitter). To
trim the servos on pistol transmitter, use the large, red trim levers on top and side of the steering wheel
(the top trims steering, and the side trims throttle/brake). On a stick transmitter, the trim levers are
located accordingly around the sticks.
RADIO OPERATION
abc
7b
ac

9
a.Check the radio steering functions. With the radio transmitter and receiver on, turn the steering wheel/stick
to the left. The front tires/wheels should turn left accordingly. If not, flip the steering servo reverse
switch.
b. Return the steering wheel/stick to neutral. The front tires/wheels should point straight forward. If not,
use the steering trim lever to correct it.
c.Turn the steering wheel/stick to the right. The front tires/wheels should turn right accordingly.
OPERATING RADIO STEERING FUNCTION
5
10
a. Check the radio throttle/brake functions. With the radio transmitter and receiver on, pull the trigger/push
the stick forward. The carburetor should be fully opened and the brake disengaged. To reverse this
function, flip the throttle/brake servo reverse switch.
b. Return the trigger/stick to neutral. The carburetor should be closed to a point where the idle has
been set (see step for ADJUSTING THROTTLE/BRAKE LINKAGE), and the brake still disengaged. If
not, use the throttle/brake trim lever to correct it.
c. Push the trigger/pull the stick backward. The carburetor opening should still be the same at neutral,
throttle spring compressed slightly, and the brake engaged.
OPERATING RADIO THROTTLE / BRAKE FUNCTION
8OPERATING RADIO STEERING FUNCTION
abc
abc
ab
Install the wheel
extension
wrench
as shown.
Install the tire/
wheel as shown.

11
a. To set the throttle/brake linkage, first the radio should be on and neutral; thus, the servo is at neutral
position.
b. With the servo at neutral, turn and adjust the brake collar to a point where the brake lever almost
engages the brake system, but not yet.
c. With the servo at neutral, loosen the throttle collars. Then, manually close the carburetor, and set
the collar (next to the spring) with the spring slightly compressed. Then, set the other collar next to
the linkage pivot.
12
a. To set the carburetor idle (small screw with spring off center on the side of carburetor body), turn the
screw as pictured. Please refer to ENGINE BREAK-IN/TUNING procedures to properly set the engine.
b. To set the high speed needle (large needle sticking out from the carburetor body), turn the screw as
pictured. Please refer to ENGINE BREAK-IN/TUNING procedures to properly set the engine.
c. To set the mid speed needle (large needle in the middle of the carburetor body), turn the screw as
pictured. Please refer to ENGINE BREAK-IN/TUNING procedures to properly set the engine.
d. To set the low speed needle (large needle in the throttle lever), turn the screw as pictured. Please
refer to ENGINE BREAK-IN/TUNING procedures to properly set the engine.
e. Remove the outer foam from filter and make it moist evenly with a few drops of fuel. If the vehicle
will be operated in an area with fine dust, use filter oil or caster oil instead of fuel and make both the
inner and outer foam moist. It is important that the foam is only moist to trap dirt and allow air passage.
With the foam too wet, limited air can pass through; therefore, limiting engine performance.
f. Install the filter boot onto the engine carburetor and make sure the air cleaner boot is securely
fastened with a zip-tie.
ADJUSTING THROTTLE / BRAKE LINKAGE
abc
ADJUSTING CARBURETOR
6
abc
def

13
abc
a. Remove the cap from fuel bottle nozzle.
b. Squeeze the fuel bottle, insert into fuel, and draw fuel into the fuel bottle.
c. Fill car's fuel tank with glow fuel.
FUEL RECOMMENDATION
Agood quality, commercially available model engine fuel containing 5% to 30% nitro with 15% to 25%
oil is recommended for initial break-in and regular run-in of this engine. Thunder Tiger also recommends
that the oil composition to be made of caster oil or a caster/synthetic blend. Fuel containing only synthetic
lubricant is much less tolerant of high temperature and lean carburetor settings; thus, may cause the
engine to become difficult to operate under normal conditions.
Less % of nitro in fuel means that the engine will produce slightly less power. Conversely, fuel with less
nitro % will have higher alcohol % which enables the engine to operate at a much lower temperature.
Thunder Tiger finds that the PRO-70BX performs best (power vs. heat) with 15% nitromethane fuel.
Oil composition in fuel is vital for a 2-cycle engine's moving internal parts. More % of lubricant means
that the fuel has more oil to lubricate the moving parts. This is especially important for ring engines such
as the PRO-70BX. Thunder Tiger finds that the PRO-70BX performs best with 20% oil.
GLOW PLUG RECOMMENDATION
The length of the glow plug and the quality of its coil have a major impact on overall performance and
reliability of the engine. The engine operates best with a platinum coil plug rated at medium to hot
temperature. The following is a list of glow plugs suitable for use in this engine: Thunder Tiger 9281,
Enya #3/#5, McCoy #9/#59, Novarossi C4S/C5S/C6S, OS A3/A5/#8, and Picco P6S/P7S.
FUELLING
7
WARNING
Thank you for purchasing a Thunder Tiger Product. Please read all instructions thoroughly before operation.
1. This product is not a toy. It is a high performance model product. It is important to familiarize yourself with the
model, its manual, and its construction before assembly or operation.
2. Do not operate model products in rain, on public roads, near crowds, near airport, or near areas with restricted
radio operation.
3. Always keep fuel away from heat and open flame. Only operate in open, well-ventilated area. Store fuel in cool,
dry area. Keep the fuel bottle cap tightly closed. Clean up any leak or excess fuel before starting the engine.
4. This product, its parts, and its construction tools can be harmful to your health.Always exercise extreme caution
when assembling and/or operating this product. Do not touch any part of model which rotates.
5. Check your radio frequency with the proper operating frequency of the area or country. Always check to see if
there are any modelers operating on the same frequency as your are.Also, check your radio for proper operation
before operating a mode.
6. Improper operations may cause personal and/or property damage. Thunder Tiger and its distributor have no
control over damage resulting from shipping, improper construction, or improper usage.
7. Thunder Tiger assumes and accepts no responsibility for personal and/or property damages resulting from the
use of improper building materials, equipment and operations. By the act of assembling or operating this product,
the user accepts all resulting liability. If the buyer is not prepared to accept this liability, then he/she should return
this kit in new, unassembled, and unused condition to the place of purchase.

14
a. Turn on the radio (transmitter first, then receiver).
b. Clip the glow plug igniter onto engine's glow plug.
c. Insert the starting tool and turn the engine over with the electric starter for a few seconds. Repeat
until the engine starts. Throttle maybe required to be opened momentarily, but release throttle back
to neutral immediately after the engine starts.
Remove the glow plug igniter from engine after engine has started and warmed up. If the engine stops
right after the igniter is removed, the carburetor setting is too rich. Please refer to engine setting section.
If engine is hard to start, the engine maybe flooded. To unflood an engine, remove the glow plug from
engine, flip the car upside down, and turn over the engine to release excess fuel. Then, reinstall the
glow plug and repeat the engine starting procedure.
PREPARING THE ENGINE
a. To start an engine, first remove the glow plug.
b. Check the glow plug by plugging it into the glow plug igniter. The glow plug element should light up
brightly. If it lights up dimly, then the glow plug igniter is low (and it needs recharging). If it does not
light up or the plug element looks distorted, then the glow plug is bad (replace with new one). After
checking, reinstall the glow plug.
c. With the radio off, manually turn the servo to open the carburetor (open throttle).
d. Install the extended 6mm hex starting tool into 12V DC starter.
e. Insert the tip of the starting tool into the engine starting hub on the back plate and turn the engine
for a few seconds to prime the engine with the starter. Repeat until the fuel reaches the carburetor.
f. Manually return the servo back to neutral.
STARTING THE ENGINE
15
a b c
8
de
cba
f

BREAK-IN
For a new engine, a fuel with low nitro rating and high oil content is highly recommended for the first 10
tanks (125cc per tank). Although one can use a fuel with nitro and oil rating combination stated within
the recommended guidelines, 5% nitro and 25% oil is best during break-in period. Please carefully follow
the procedures below for a proper break-in, first 10 tanks of fuel:
1. Check the carburetor's high speed needle. With a fresh new engine, fully close the high speed needle,
then open it 3 turns from fully closed.
2. Check the carburetor's idle setting. Set the idle screw so that the carburetor has 2mm opening when
the throttle is closed.
3. Follow the procedure for starting the engine.
4. Once the engine is started, run the car in an open, flat area. Try to vary throttle positions and operate
with smooth throttle transitions. Keep in mind that the new engine should be run at mostly low to mid
throttle with very little time at full throttle (no more than 1 second).
5. Set the carburetor to break-in setting accordingly.
If the engine stalls at low RPM, then set the low speed mixture leaner by turning in (clock
wise) the low speed needle 1/8 turn. It is normal for engines to stall during the first
10 tanks of fuel because break-in setting is always rich.
If the engine stalls at full throttle (no more than 1 second), then set the high speed mixture
leaner by turning in (clockwise) the high speed needle 1/8 turn.
If the engine races at full throttle (no more than 1 second), then set the high speed mixture
richer by turning out (counterclockwise) the high speed needle 1/8 turn.
6. The engine should be set as rich as possible before it stalls at full throttle (no more than 1 second).
To do this, turn the high speed needle out (counterclockwise) 1/8 turn at a time until the engine stalls.
Then, turn this needle back 1/8 turn clockwise, and follow STEP #3 and #4 for the next 2 tanks of fuel.
7. On the 3rd tank of fuel, set the high speed mixture leaner by turning in (clockwise) the high speed
needle 1/8 turn. Repeat STEP #4.
8. On the 6TH tank of fuel, set the high speed mixture leaner by turning in (clockwise) the high speed
needle 1/8 turn. Repeat STEP #4.
9. Finish the break-in process by running 3 more thanks of fuel and repeating STEP #4.
10. After the 10th tank, the engine should be properly broken-in and ready for normal use. Follow the
engine tuning procedure to set up the engine carburetor for normal use.
ENGINE TUNING
The included PRO-70BX engine is a ring engine, and as such, it will need to be tuned differently than a
regular ABC engine. The ring on the piston requires lubrication for proper function. To achieve proper
lubrication, the engine needs to be run with high oil content fuel and at rich carburetor setting.
After proper break-in, the new engine is ready for regular operations. For normal use, please use the
recommended fuel formula described in the fuel section, and follow the procedures below to achieve
proper carburetor setting. Clockwise needle turn will provide leaner setting (lower fuel to air mixture),
and counterclockwise needle turn will provide richer setting (higher fuel to air mixture). Do not perform
this procedure until the engine has been properly broken in:
1. Check the carburetor's idle setting. Set the idle screw (small screw with spring off center on the side
of carburetor body) so that the carburetor has 2mm opening when the throttle is closed.
9

10
2. Check the carburetor's mid speed needle / spray bar. Set the mid speed needle / spray bar (small
screw in the center and on the side of carburetor body) so that its outer most edge sits flush with the
carburetor body side. Once this is set, do not move it again. Only make engine tuning adjustments
with idle screw, high speed, and low speed needles.
3. Follow the procedure for starting the engine.
4. To set the idle, turn the idle screw clockwise (higher RPM) or counterclockwise (lower RPM). Basically,
the idle needs to be set at the lowest possible RPM before the engine stalls.
5. With a running engine, run the car back and forth in a straight line (full throttle achieved during each
passage) in an open parking lot. Repeat and note the sound of the exhaust. Do not hold the throttle
open when the engine is without load (car off the ground), or serious engine damage may result.
6. Review the sound noted in STEP #5. If the exhaust does not reach a high pitch note, then the high
speed setting is rich. Turn the high speed needle (long needle extending from carburetor body, pointing
up) 1/8 turn clockwise, and repeat STEP #3.
7. Repeat STEP #6 until the engine reaches peak setting (turning in the high speed needle will not yield
ahigher pitch, and it may even cause the engine to bog at full throttle; however, turning out the needle
will cause the engine's full throttle RPM to drop a little). For normal operations, the optimum setting
for high speed needle should be 1/2 to 1/4 turn counterclockwise from the peak setting. Continuous
engine operation at peak setting may result in overheating and engine damage.
8. To set the low speed needle (small hex screw inside the carburetor's slide/lever), the engine needs to
be broken in and high speed needle needs to be set first.
9. Repeat STEP #5 every 12 seconds (2 seconds at full throttle and 10 seconds at idle).
10. The engine RPM at idle should remain constant, drop to a lower RPM after a few seconds, and remain
at that low RPM without stalling.
If the engine stalls after a few seconds at idle, then the low speed setting is too rich.
Turn the low speed needle clockwise 1/8 turn.
If the engine RPM stays the same or races at idle, then the low speed setting is too lean.
Turn the low speed needle counterclockwise 1/8 turn.
11. Repeat STEP #9 and #10 until proper engine low speed setting is achieved.
When running the PRO-70BX, the optimum carburetor setting is rich (high speed needle set at 1/2 to
1/4 turn counterclockwise from the peak performance setting), and as such, it is normal for the engine
to sound rich and expel a lot of smoke. Tune this engine so that it is at maximum fuel delivery (both
high and low speed) without stalling. At this optimum setting, the engine should continue to operate at
normal temperature range (low 100s C or mid 200s F); thus, consistent engine temperature and performance
over extended period of time. At peak carburetor setting (not optimum setting), engine performance will
be much better initially, but it will soon overheat and become inconsistent. Never operate this engine at
peak or lean carburetor setting.

Meanest hop-ups for EK-4 S2 enthusiast
Ferodo brake disc
Adjustable turnbuckles
Carbide hinge pins
ERGAL center differential mount
ERGAL one piece torque rod, front /rear
ERGAL chassis, 5mm
ERGAL front and rear shock towers
ERGAL front upper arm mount
ERGAL transmission plates
ERGAL center diff top plate
ERGAL servo saver top plate
ERGAL steering slider
ERGAL battery post
ERGAL servo saver post
ERGAL FR plate FR trans
ERGAL FR plate RR trans
ERGAL RR plate FR trans
ERGAL rear toe-in block, 2 degree
ERGAL front knuckle
ERGAL engine mount
ERGAL heat sink head
Carbon battery plate
Carbon servo tray
Aluminum shock set & mount
Center & rear universal
THUNDER TIGER CORPORATION www.thundertiger.com.tw
Specifications
Wheelbase: Adjustable from 315mm to 320mm
Front Track Width: Adjustable from 295mm to 305mm
Rear Track Width: 300mm
Front Kick-Up: 0˚
Front Caster: Adjustable from 18˚to 25˚
Rear Anti-Dive: 2˚
Rear Toe-in: 2˚
All Up Weight: 5400g
PRO-70BX ENGINE WITH
UPGRADE HEAT SINK SHOWN
No.6219 EK-4 S2 UNLIMITED CONVERSION KIT