MAX-21VZ-B V-Spec OWNER'S INSTRUCTION MANUAL 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.
CONTENTS SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S.
SAFETY INSTRUCTIONS AND WARNINGS ABOUT YOUR O.S. ENGINE Remember that your engine is not a "toy", but a highly efficient internalcombustion 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.
WARNINGS Never operate your engine in an enclosed space. Model engines, like automobile engines, exhaust deadly carbon-monoxide. Run your engine only in an open area. 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 engines generate considerable heat. Do not touch any part of your engine until it has cooled.
NOTES This engine is intended for model cars. Do not attempt to use it for any other purpose. The wearing of safety glasses is also strongly recommended. Mount the engine in your model securely, following the manufacturers' recommendations, using appropriate screws and locknuts. 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. Install an effective silencer (muffler).
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 glowplugignition 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.
Around TDC ENGINE CONSTRUCTION With this engine, the piston will feel tight at the top of its stroke Piston (TDC) when the engine is cold. Cylinder Liner This is normal. The cylinder bore is a little tapered. The piston and cylinder are designed to achieve a perfect running Crankshaft clearance A little tapered when they reach their running temperatures. When the engine is cold. When the engine is hot.
NOTES WHEN APPLYING AN ELECTRIC STARTER Do not over-prime. This could cause hydraulic lock and damage the engine on application of the electric starter. If over-primed, remove glowplug, close needle-valve and apply starter to pump out surplus fuel. Cover the head with waste to prevent pumped out fuel coming into your eyes. NOTE As delivered, the engine has its carburetor lightly fit into its intake. Secure it changing its angle according to the car chassis.
Standard accessories ABOUT THE ENGINE Glow Plug P3 T-type head (Turbo head) 1piece The MAX-21 VZ-B V-Spec is a high performance 3.5cc class power unit for oneeight-scale radio-controlled 'off-road' or 'buggy' cars. It has been expressly designed for racing competitions. T-type plug (turbo plug) design improves the power, fuel consumption and durabili- (Hot Type) Cylinder-head gasket (0.1mm) 1 sheet Exhaust Seal Ring 1 piece ty. The new 21 C carburetor is supplied with 8mm and 9mm dia.
BEFORE STARTING Tools, accessories, etc.The following items are necessary for operating the engine. Optional Extras T-2050 TUNED SILENCER ASSEMBLY This is designed specifically for 3.5cc 'off-road' model car engines. GLOW PLUG T-Type (Turbo Plug) P3 is supplied with the engine. As replacement, suggested O.S. plugs are P3 and P6. SUPER AIR CLEANER 203 ASSEMBLY This is a heavy-duty wet type air cleaner designed specifically tor 3.5cc 'off-road' model car engines.
LONG SOCKET WRENCH WITH PLUG GRIP Recommended for easy removal and replacement of the angled and recessed glowplug, the O.S.Long Socket Wrench incorporates a special grip. 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.
STARTER BOX For starting the engine. BASIC ENGINE PARTS Heatsink Head 7.2V BATTERIES FOR STARTER BOX Batteries for starter box. Select according to the starter box used. Be sure to full charge before using. Carburetor Type 21 C FUEL PUMP For filling the fuel tank, a simple, polyethylene "squeeze" bottle, with a suitable spout, is required. Exhaust 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 Four adjustable controls are provided on this carburetor. The Needle-Valve: For adjusting the mixture strength when the throttle is fully open. Carburetor Reducer Needle Valve Mixture Control Valve Assembly Screw The Mixture Control Screw: For changing the mixture strength at mid speed and acceleration. (Do not rotate the screw more than one turn.
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. 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 P3 and P6.
INSTALLATION OF THE STANDARD ACCESSORIES Fitting the carburetor reducer Replace the reduce according to the course conditions. Fitting the glow plug. Insert P3 plug supplied into heatsink-head carefully, making sure that it is not cross-threaded before tightening firmly. (All the O.S. T-Type plugs including the P3 are not supplied with a washer.) 9mm (Blue) Fitted with the carburetor when leaves the factory. Suitable for high speed (wide) and flat course which requires power.
INSTALLATION OF THE CARBURETOR ENGINE INSTALLATION As delivered, the engine has its carburetor lightly installed in the intake boss. Secure it as follows. 1. 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. Make sure that the vehicle's engine mounting surfaces are level and in the same plane.
STARTING THE ENGINE & RUNNING-IN ("Breaking-in") For long life and high performance, every engine needs to be 'run-in' or 'broken-in'. With care, running-in of the MAX-21VZ-B V-Spec can be carried out with the engine installed in the vehicle. Be sure to install the air-cleaner on the carburetor and use a muffler-pressurized fuel system. The following procedure is suitable for these engines when the O.S. T-2050 tuned silencer and a fuel containing up to 30% nitromethane are used.
Turn the needle-valve clockwise slowly until it stops. This is the fully closed position. Do not force to turn further. Turn the engine with starter box to draw the fuel into the engine. Open the Needle-Valve 3 turns from the fully closed position. Switch on the transmitter and receiver and set the throttle very slightly open from the idling position. Needle Valve Starter Box Throttle opening at idling approx 0.3-0.5mm Open Close Deliver fuel into the carburetor.
Now connect glowplug battery lead to heat the plug filament and start the engine. Glow Plug Igniter Air Cleaner When the engine starts, first allow it to operate in short runs at the very rich starting settings, with the glowplug battery still connected and the driving wheels clear of the ground. The rich mixture will, under these conditions, provide adequate lubrication and cooling, indicated by profuse smoke from the exhaust.
again. In the event of any major working parts (e.g. piston/cylinder liner assembly) being replaced or the fuel being changed, especially to high nitro fuel, the complete running-in should be repeated. To stop the engine, close the throttle to idling speed, then shut it off completely with the trim lever on the transmitter. To cut off the fuel supply, pinch the fuel delivery tube to the carburetor.
FINAL ADJUSTMENT Final adjustment should be carried out only after the running-in has been completed. Needle Valve Continue with further runs, gradually reducing the Needle-Valve setting and aiming to achieve the highest straight-line speed. Remember, however, that, if the Needle-Valve is shut down too far, the engine will overheat and, accompanied by visibly diminished exhaust smoke, the model will lose speed. At this point, throttle down immediately, stop the vehicle and reopen the Needle-Valve 45-90° .
Warning! Mixture adjustments (whether via the Metering Needle, or the Needle-Valve) cannot be made accurately under 'no-load' conditions, which, in any case, are not advised, since such operation carries the risk of seriously damaging the engine through over-revving and overheating. With the engine running, close the throttle and allow it to idle for about five seconds, then reopen the throttle fully.
Finally, beyond the nominal break-in period, a slight readjustment toward a leaner needle setting may be required to maintain maximum performance. Carburetor Body CARBURETOR CLEANLINESS Ball Link Rotate the Metering Needle until its slotted head is flush with the ball link body. This is the standard position. Metering Needle Slide Valve The correct functioning of the carburetor depends on its small fuel orifices remaining clear.
CARE AND MAINTENANCE 1.The minute particles of foreign matter, that are present in any fuel may, by accumulating and partially obstructing fuel flow, cause engine performance to become erratic and unreliable. O.S. 'Super-Filters' (large and small) are available, as optional extras, to deal with this problem. One of these filters installed to the pickup tube inside your refueling container, will prevent the entry of foreign material into the fuel tank.
CHECKING THE ENGINE Engine will not develop normal performance after long time running due to wearing of parts. It is suggested to replace necessary parts when the following symptoms are detected. Engine sound changes and easily overheats. Power has dropped extremely. Idling is unstable and/or engine tends to stop at idling. Fitting Dust Caps When storing the engine, fit it to exhaust port, carburetor, etc. to prevent dust entering inside the engine.
GUARANTEE This engine is constructed from the very best materials available and to the very highest engineering standards, using the most advanced precision machinery. However, the extremely high stresses imposed by car racing operation under very severe conditions, as well as stresses which are exacerbated by the use of powerful fuels containing very high concentrations of nitromethane, constitute hazards which are beyond a manufacturer's control.
TROUBLE SHOOTING Engine fails to fire. Fuel tank is empty. Fuel not reaching the engine. Fill the tank with fuel and repeat Priming procedure. Glowplug element is burnt out. Glowplug battery discharged Clogged fuel filter Air cleaner and silencer inside is dirty. Replace glowplug. Recharge or replace the battery. Clean or replace fuel filter. Replace cleaner element and clean inside silencer. Over priming Remove glowplug and pump excess fuel. Fuel tubing is disconnected.
Engine fires intermittently but does not run. Insufficient fuel in the tank. Fill the tank with fuel. Deteriorated glowplug Replace glowplug. Clogged fuel filter Air cleaner and silencer inside is dirty. Clean or replace fuel filter. Replace cleaner element and clean inside silencer. Engine overheated Wait until engine is cooled. Incorrect clutch release Adjust the tension of clutch spring. Too immediately disconnecting plug battery Do not disconnect plug battery and wait until r.p.m.
Unstable idling Unsuitable glowplug Use suggested glowplug in the instructions. Unsuitable fuel Do not use extremely high nitro or low oil fuel. Extremely light flywheel Add suitable load. Silencer is disconnected or has play Install silencer securely. Not reaching expected peak r.p.m. Insufficient warming up or running-in. Set the needle only after warming up. Complete running-in. Silencer or manifold is not securely connected or disconnected. Replace seal ring.
Poor response Deteriorated glowplug Replace glowplug. Incorrect carburetor settings Readjust low r.p.m. range with metering needle and mixture control valve. Incorrect setting of transmitter Exponential function. Check the transmitter setting. Poor r.p.m. drop Too much throttle opening at idling. Close metering needle to adequate position to lower idling r.p.m. Incorrect carburetor fitting Fit carburetor securely.
ENGINE EXPLODED VIEW CM3X18 1 17 2 3 4 5 8 C.M2.6X7 6 7 6 16 9 15 C.M2.
ENGINE PARTS LIST No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Code No. Description 22105000 22105100 123764010 22103010 23906000 23817000 23755000 23818050 23715000 23981700 23731000 23751010 23730010 22102000 23764020 23757000 23763010 71641300 22826140 71533000 22884250 Outer Head Inner Head Head Gasket (2pcs.) Cylinder & Piston Assembly Piston Pin Piston Pin Retainer (2pcs.
CARBURETOR EXPLODED VIEW * Type of screw C. Cap Screw M Oval Fillister-Head Screw F.FIat Head Screw N . Round Head Screw S.
CARBURETOR PARTS LIST No. Code No. Description 1 23781600 Mixture Control Valve Assembly "0" Ring (L) (2pcs.) 1-1 46066319 "0" Ring (S) (2pcs.) 1-2 22781800 2 23618190 Needle Valve Assembly Needle Assembly 2-1 23618197 "0" Ring (2pcs.) 2-2 46066319 Needle Holder Assembly 2-3 23618194 2-4 23818176 Fuel Inlet (No.9) 3 71533010 Carburetor Reducer 9mm (BLUE) w/ "0" Ring (2pcs.
O.S. GENUINE PARTS & ACCESSORIES T-2050 EXHAUST HEADER PIPE ASSEMBLY GLOWPLUG P3 P6 (71641300) (71641600) (72106150) Exhaust Header Pipe (72106155) Header Pipe Spring (2pcs.) (72101272) Exhaust Seal Ring (2pcs.) (22826140) T-2050 TUNED SILENCER COMPLETE SET T-2050 TUNED SILENCER ASSEMBLY (72106060) T-2050 Tuned Silencer Body (72106070) (72106061) T-2050 Tuned Silencer Assembly Pressure Nipple (72106041) Exhaust Seal Ring (2pcs.) (72106060) (22826140) Joint Spring (3pcs.
O.S. GENUINE PARTS & ACCESSORIES T-2030 TUNED SILENCER SUPER AIR CLEANER 203 EXHAUST SEAL RING (72106030) (72413000) (22826140) 21 RZ EXHAUST HEADER PIPE (2pcs.) 203 Filter Element (4pcs.) (72413200) (72101270) CAP SCREW SET SUPER JOINT TUBE 21 M2.6x7(10pcs.) (72106300) DUST CAP SET 3mm (5pcs.) (73300305) 8mm (3pcs.) (73300812) 16mm (3pcs.) (73301512) 18mm (3pcs.
THREE VIEW DRAWING SPECIFICATIONS Displacement Bore Stroke Practical R.P.M. Power output Weight 3.46cc(0.211cu.in.) 16.6mm (0.654in.) 16.0mm (0.630in.) 3,000-40.000 r.p.m. 2.48ps / 33.000 r.p.m. 360g (12.7oz.
6-15 3-Chome Imagawa Higashisumiyoshi-ku Osaka 546-0003, Japan TEL. (06) 6702-0225 FAX. (06) 6704-2722 URL: http://www.os-engines.co.jp (C) Copyright 2004 by O.S.Engines Mfg. Co.. Ltd. All rights reserved. Printed in Japan.
