O.S. engine MAX-21VZ-R Setup guide
It is of vital importance, before attempting to
operate your engine, to read the general
'SAFETY INSTRUCTIONS AND WARNINGS'
section on pages 2-5 of this booklet and to strictly
adhere to the advice contained therein.
Also, please study the entire contents of this
instruction manual, so as to familiarize yourself
with the controls and other features of the
engine.
Keep these instructions in a safe place so that
you may readily refer to them whenever
necessary.
It is suggested that any instructions supplied
with the vehicle, radio control equipment, etc.,
are accessible for checking at the same time.
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2
Remember that your engine is not a "toy", but a highly efficient internal-
combustion machine whose power is capable of harming you, or others, if it is
misused.
As owner, you, alone, are responsible for the safe operation of your engine, so act
with discretion and care at all times.
If at some future date, your O.S. engine is acquired by another person, we would
respectfully request that these instructions are also passed on to its new owner.
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE
The advice which follows applies basically to ALL MODEL ENGINES and is
grouped under two headings according to the degree of damage or danger
which might arise through misuse or neglect.
WARNINGS NOTES
These cover events which
might involve serious (in
extreme circumstances, even
fatal) injury.
These cover the many other
possibilities, generally less obvious
sources of danger, but which, under
certain circumstances, may also
cause damage or injury.
WARNINGS
Model engine fuel is poi-
sonous. Do not allow it to
come into contact with the
eyes or mouth. Always
store it in a clearly marked
container and out of the
reach of children.
Model engine fuel is also
highly flammable. Keep it
away from an open flame,
excessive heat, sources of
sparks, or anything else
whichmightigniteit.Donot
smokeorallowanyoneelse
to smoke, near to it.
Never operate your engine in an en-
closed space. Model engines, like
automobile engines, exhaust deadly
carbon-monoxide. Run your engine
only in an open area.
Model engines generate
considerable heat. Do not
touch any part of your
engine until it has cooled.
Contact with the muffler
(silencer), cylinder head
or exhaust header pipe, in
particular, may result in a
serious burn.
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3
This engine is intended for model cars.
Do not attempt to use it for any other
purpose.
Mount the engine in your model
securely, following the manufacturers'
recommendations, using appropriate
screws and locknuts.
Install an effective silencer (muffler).
Frequent close exposure to a noisy
exhaust (especially in the case of the
more powerful highspeed engines)
may eventually impair your hearing
and such noise is also likely to cause
annoyance to others over a wide area.
The wearing of safety glasses is also
strongly recommended.
Take care that the glowplug clip or
battery leads do not come into contact
with rotating parts. Also check that the
linkage to the throttle arm is secure.
For their safety, keep all onlookers
(especially small children) well back
(at least 20 feet or 6 meters) when
preparing your model for running.
NOTES
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4
NOTES
To stop the engine, fully retard the
throttle stick and trim lever on the
trans-mitter, or, in an emergency, cut
off the fuel supply by pinching the fuel
delivery line from the tank.
•
Warning! Immediately after a glowplug-
ignition engine has been run and is still
warm, conditions sometimes exist
whereby it is just possible for the engine
to abruptly restart if it is rotated over
compression WITHOUT the glowplug
battery being reconnected.
•
5
BASIC ENGINE PARTS
With this engine, the piston will feel tight at the
top of its stroke when the engine is cold. This is
normal. The piston and cylinder are designed to
achieve a perfect running clearance when they
reach their normal running temperatures.
Heatsink Head
Carburetor
Type 20K
Crankshaft
Crankcase
Mounting Lugs
Exhaust
As delivered, the engine has its carburetor lightly
fit into its intake. Secure it changing its angle
according to the car chassis.
NOTE
Standard accessories
Glow Plug P7 Cylinder-head gasket (0.1mm)
Exhaust Seal Ring Dust Cap 3, 16, 18
The MAX-21VZ-R is high performance 3.5cc
class power unit for one-eighth-scale radio-
controlled 'Track racing' cars. It has been de-
signed to meet the exacting requirements of
the world's most expert drivers. An exhaustive
program of research, development and proto-
type testing has resulted in one of the most
powerful production model racing car engines
currently available.
NOTE
The engine is fitted with one each of 0.1mm and
0.2mm cylinder-head gasket when leaves the
factory. Another 0.1mm head gasket is supplied
with the engine. You may addit at initial running-
in, when a glow plug tends to burn out due to high
temperature and / or high humidity or when you
prefer fuel economy to power.
Cover Plate
6
ENGINE INSTALLATION
Make sure that the vehicle's engine mounting
surfaces are level and in the same plane. Poor
installation may cause distortion of the
crankcase, bearings, etc., resulting in erratic
running and loss of performance.
The recommended screws for securing the
engine are 3mm or 4-40 steel Allen hexagon
socket type.
If existing holes in the engine mount do not align
perfectly with engine mounting lugs, enlarge
themslightlywithaneedle-filesothatscrewsare
in alignment with the mounting holes.
Chassis
Chamfer inside edges of bearers.
INSTALLATION OF THE CARBURETOR
Asdelivered,theenginehasitscarburetorlightly
install into its intake boss. Secure it as follows.
Loosen the retainer screw, rotate the
carburetor to its correct position and make
sure that it is pressed well down into the
intake boss, compressing the rubber gasket,
before retightening screw.
1.
2. Rotate the
retainer nut
gently until
it stops.
Tighten a
further
120-180˚
Rotate the retainer
screw gently until it
stops, then tighten
a further 120-180˚.
Do not overtighten
the screw as this
will damage the
carburetor body.
1.
2. Install the exhaust seal ring supplied.
Insert carefully into heatsink head, making
sure that it is not cross-threaded before
tightening firmly.
Do not allow bottom
of crankcase to
touch chassis.
7
Since the compatibility of glowplug and fuel may have
a marked effect on performance and reliability, it may
be worthwhile to choose the R/C type plug found
most suitable after tests. Recommended O.S. plugs
are P7. Carefully install plug finger-tight, before final
tightening with the correct size plug wrench.
GLOWPLUG
The role of the glowplug
Glowplug life
Particularly in the case of very high performance
engines,
glowplugs must be regarded as expendable
items. However, plug life can be extended and engine
performance maintained by careful use, i.e.:
Install a plug suitable for the engine.
Use fuel containing a moderate percentage of
nitromethane unless more is essential for racing
events.
Do not run the engine too lean and do not leave the
battery connected while adjusting the needle.
With a glowplug engine, ignition is initiated by the
application of a 1.5-volt power source. When the
battery is disconnected, the heat retained within the
combustion chamber remains sufficient to keep the
plug filament glowing, thereby continuing to keep the
engine running. Ignition timing is 'automatic' : under
reduced load, allowing higher rpm, the plug becomes
hotter and, appropriately, fires the fuel/air charge
earlier; conversely, at reduced rpm, the plug become
cooler and ignition is retarded.
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Apart from when actually burned out, a plug may
need to be replaced because it no longer delivers its
best performance, such as when:
When to replace the glowplug
Filament surface has roughened and turned white.
Filament coil has become distorted.
Foreign matter has adhered to filament or plug
body has corroded.
Engine tends to cut out when idling.
Starting qualities deteriorate.
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8
TOOLS, ACCESSORIES, etc.
FUEL
Generally, it is suggested that the user selects a fuel
that is commercially available for model two-stroke
engines and contains 10-30% nitromethane. As a
starting point, we recommend a fuel containing 20%
nitromethane, changing to a fuel containing more nitro if
necessary. When the brand of fuel is changed, or the
nitro content increased, it is advisable to repeat the
running-in procedure referred to in the RUNNING-IN
paragraphs.
The following items are necessary for operating the
engine.
REMINDER!
Model engine fuel is poisonous. Do not
allow it to come into contact with the eyes
or mouth. Always store it in a clearly
marked container and out of the reach of
children.
Model engine fuel is also highly
flammable. Keep it away from open flame,
excessive heat, sources of sparks, or
anything else which might ignite it. Do not
smoke or allow anyone else to smoke,
near to it.
Please note that with high-nitro fuels, although power
may be increased for competition purposes, glowplug
elements do not last so long and engine life will be
shortened.
BATTERY INTEGRATED GLOWPLUG HEATER
Commercialy available handy
glowplug heater in which the
glowplug battery and battery
leads are integrated.
FUEL PUMP
For filling the fuel tank, a simple,
polyethylene "squeeze" bottle,
with a suitable spout, is required.
STARTER BOX
For starting the engine.
9
LONG SOCKET WRENCH
Recommendedfor easyremoval
and replacement of the angled
and recessed glowplug, the
O.S.Long Socket Wrench
incorporates a special grip.
SILICONE FUEL LINE
Heatproof silicone tubing of
approx. 5mm o.d. and 2mm i.d.
is required for the connection
between the fuel tank and
engine.
CARBURETOR CONTROLS
The Needle-Valve:
•
The Mixture Control Screw:
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The Throttle Stop Screw:
For setting the minimum idling speed:
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Four adjustable controls are provided on this
carburettor.
For adjusting the mixture strength when the throttle
is fully open.
For adjusting the mixture strength at part-throttle
and idling speeds, to obtain steady idling and
smooth acceleration to mid speeds.
Needle Valve
Mixture Control Valve
Assembly Screw
Throttle Stop Screw
NOTE: Readjustment may be necessary,
occasionally to allow for changes in fuel formula
gear ratio or clutch engagement point.
The Metering Needle:
•
Metering Needle
For changing the feeling at mid speads and
acceleration. (Do not rotate the screw more chan
one turn.)
10
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