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ZZ.21C
CERAMIC
user guide
ORDER#:
32120
2.92 HP
40.000 RPM
MA00232
© LRP electronic GmbH 2011
7. carburetor
5. exhaust system
8. run-in
2. fuel
6. head clearance
1. specification
3. airfilter
4. glowplug
Engine size
.21 (3.49ccm)
Exhaust
Rear
Bore
16.30mm
Stroke
16.80mm
Liner
ABC
Number of ports
3+1 (3x transfer-, 1x exhaust-port)
Main bearing
Ceramic
Crankshaft
14.0mm / DLC coating / precision balanced / with silicone insert
Crankcase
Black XTEC C6 .21 Heavy-Duty Competition
Piston
Specially lightened, high-silicium alloy
Connecting Rod
Oversized, knife-edge shaped, extra strong aluminium,
double bushings
Glowplug
Hot Turbo style, LRP Turbo WT3 (No. 35135) included
Carburetor
XTEC thermal protected WorksTeam carburetor.
Aluminium 6.0, 6.5 and 7.0mm inserts included.
Power Output*
2.92 HP
Max. RPM*
40.000
Weight
345g
*Figures may vary depending on used fuel, exhaust system and tuning.
Never use regular gasoline or airplane fuel. Use fresh 2-stroke model car fuel only! We recom-
mend using our line of LRP Energy Power fuels (No. 35711: 25% 1L / No. 35731: 25% 3,5L). For
the LRP ZZ.21C Ceramic engine, we recommend a fuel with 25% nitro. Never exceed 36% nitro.
A higher nitro content will decrease your engine‘s lifetime.
A good airfilter is very important for the life of your engine. Never run without an airfilter, as
quick and permanent damage will result! Don’t forget to impregnate the airfilter with a suitable
oil before usage. Carefully clean the airfilter at least after every tenth tank. Replace the airfilter
every 3 litres (~1 gallon) of usage.
We recommend the use of our LRP Hi-Flow 2-Stage oval airfilter (No. 36565) together with our
LRP Hi-Flow airfilter oil (No. 36590).
Use only Turbo style glow-plugs (also known as conical style plugs) for this engine. We recom-
mend using our line of high-quality LRP Platinum / Iridium WorksTeam glowplugs (No. 35135
- No. 35145, availabe as WT3 and WT4). Check them frequently and never run with worn-out or
old glow-plugs since they could damage your engine. They turn dull when your engine was too
lean and should be replaced. They should stay bright like chrome. If the glowplugs wear out too
fast, an additional 0.1mm shim between burnroom and liner is recommended. Whenever you
have trouble with the engine stalling for no reason, replace the glow-plug first!
TIP: Our LRP team always uses a LRP Platinum / Iridium WorksTeam WT3 (No. 35135) plug
for the LRP ZZ.21C Ceramic engine.
Dear Customer,
thank you for your trust in this LRP product. By purchasing a LRP nitro engine, you have chosen
a high-performance and highly sophisticated product, which doesn´t make any compromise
between maximum performance and easy tuneability. We hope you enjoy your new engine.
Please read the following instructions carefully before you start using your LRP ZZ.21C Ceramic
engine. This user guide contains important notes for the installation, the safety, the use and the
maintenance of this product. Thus protecting yourself and avoid damages of the product.
Proceed according to the user guide in order to understand your LRP ZZ.21C Ceramic engine
better. Please take your time as you will have much more joy with your product if you know it
exactly.
This user manual shall be kept in a safe place. If another customer is using this product, this
manual has to be handed out together with it.
Never run without a pipe since this will cause excessive overheating and may damage your
engine. A good pipe has a very huge effect on the performance of a 2-stroke engine. For the
LRP ZZ.21C Ceramic engine, we recommend using our high-quality LRP Enduro-46 1/8 Off-Road
Exhaust System (No. 36250) for maximum performance.
We recommend a real head clearance between piston and burnroom of about 0.60-0.70mm
(0.024-0.027“) or more, when the piston is at Top Dead Center. The real head clearance can be
calculated as follows:
Real head clearance = Thickness of head shims + 0.25mm*
We suggest to start with 0.35mm (0.014“) shims underneath the combustion chamber. You may
want to adjust the shims depending on nitro-content (see table) or track layout. Large tracks may
require an extra 0.10mm (0.004“) shim to reach higher topspeed and improved fuel consumption,
but this will decrease acceleration slightly.
Nitro content
16%
20%
25%
30%
Real head clearance
0.60mm / 0.024“
0.65mm / 0.025“
0.70mm / 0.027“
0.80mm / 0.031“
Head shims
0.35mm / 0.014“
0.40mm / 0.015“
0.45mm / 0.016“
0.55mm / 0.022“
* (that‘s due to the internal construction of the engine and the compression of the head shims, when the cooling
head is mounted)
The factory settings of the engine are as following and are a good starting point for you, if you
are not satisfied with your carburetor settings. Turn in the needles completely (Caution: Do not
overtighten them!) and loosen them the required number of turns again:
Idle screw (#1):
Adjusts the air flow when carburetor is fully
closed. Turn CW for higher idle-speed and CCW
for lower idle-speed. Should be open approx.
0.5mm.
Mid range needle (#2):
Adjusts the mid/low-speed flow rate of the fuel.
Turn CW for leaner and CCW for richer setting.
Main speed needle (#3):
Adjusts the main flow rate of the fuel (when the throttle is opened
significantly). Turn CW for leaner and CCW for richer setting.
Third needle (#4):
Should always stay in the factory setting exactly flush with the carburetor body and should not
be changed.
Carburetor venturi inserts:
In order to affect the fuel/air mixture, you can use different venturi inserts on this carburetor.
These are to finetune your engine to different track layouts. There are three different venturis
coming with the engine: 7.0mm, 6.5mm and 6.0mm.
- 7.0mm has the most power, 6.0mm has the best fuel mileage.
Proper run-in of the engine is a very important step in ensuring that you get the highest perfor-
mance and lifetime of your engine. Take your time for proper run-in.
Do not use run-in benches,
but use your car for run-in.
Use the same fuel as you will be using for the life of the engine.
Special run-in fuel is not needed. If your engine doesn’t start easily you may try loosen the glow-
plug by ½-turn to decompress the engine and try again. Don’t forget to tighten the glow-plug
again once the engine started!
Procedure:
• Start the engine and set the main-needle very rich, i.e. excessive smoke coming from the
muffler. The factory settings are a good starting point.
• Let the engine idle for 2mins first to warm it up.
• Now start driving your car, it will be slow and sluggish, but this is an important step.
• Do not allow the engine to rev-up too high, run the engine at half speed on the straightaway.
• The engine should not be too cold and not too hot during run-in, 70-80°C (160-180°F) is per-
fect.
• Let the engine cool down for 15mins after each tank during the run-in period.
• We recommend doing so for 10 tanks of fuel before you start tuning your engine.
LRP electronic GmbH
Wilhelm-Enssle-Str. 132-134
73630 Remshalden
Germany
www.LRP.cc
• Main speed needle (#3):
3 1/4 turns
• Mid range needle (#2):
2 1/2 turns (starting from the needle being flush with the ball
link)
• Third needle (#4):
Exactly flush with the carburetor body
