The M-4R is a 4 port engine with tuned crankshaft and represents the most powerful and speedy 1/8 off-road engine of the Ultimate Engines line, with great and linear power at both low and high R.P.M. It boasts the most advanced technology and a top level human capital that team up to further improve fuel mileage, overall performance and reliability.
The M-4R has all what an engine needs to compete against other market leading engines, but at an affordable and very competitive price for a top quality race engine.
Ceramic bearings have many advantages over standard steel bearings, such as decreased weight, higher RPM capabilities, increased corrosion and wear resistance, as well as reduced friction and vibration.
Talking about engines and engine bearings is very important to make sure that the fuel we are using is appropriate to ensure that bearing races and balls are protected with a film of oil which will reduce wear and friction. It is for this reason that we always recommend using Nitrolux - The Ultimate Fuel Generation.
It stands out the exclusive oversized cooling head 100% also used on the M-5 and M-8 engines to keep the engine cooler and improve performance at high temperatures. It’s been drilled and milled out to make it lighter and keep the overall center of gravity of the engine low. Besides this, the diameter of the central hole of the head where the glow plug fits has been reduced to better measure the temperature for those who use a temp gun .The reason to do this is to avoid that the temp gun touches the glow plug when measuring the temperature and have a more accurate temp reading.
The carburetor chosen for the M-4R engine is the plastic one from Novarossi. It is a "reverse" type with a sliding throttle valve. It provides high idle stability, more precise tuning and higher mid/top range power.
The exclusive 13mm turbo crankshaft has also been designed by the team and hand tuned and lightened to reduce rotation weight and is surprisingly strong and reliable thanks to our special steel and heat treatment.
The shape of the rear cover helps to optimize the crankcase filling and reduces dead space. The steel plate helps to reduce conrod-backplate friction and increases the life of the conrod and improves engine efficiency and performance.
This 4 transfer ports sleeve is the best option to provide high linear power at each RPM and low fuel consumption.
PISTON & CONROD
The R7 conrod is machined from a super light aluminum that has been checked ultrasonically. The unique shape of the R7 rod creates less turbulence inside the engine.
The material of the piston has been chosen for its excellent strength to weight properties. The flat shape of the top of the piston improves the efficiency of the engine.
Each piston is coupled with the sleeve to get the best compression and longevity. This operation is made by hand, one by one and checked by a specific precise measurement tool.
TURBO PLUG UNDERHEAD BUTTON
The combustion chamber has a special shape to increase the performance during combustion. The sealing o-ring avoids vibrations and also protects the assembled sleeve/crankase from external dust. This head button is for Turbo plugs, not Standard plugs. It’s been market with an arrow to make sure you always assemble it correctly.
The Front Engine Bearing is a rubber sealed Ceramic “Super Speed Series” or “3S” from Ultimate Racing. This bearing is designed to fit the Ultimate M-4R, M-5 and M-8 engines, and will also fit any other .21 competition buggy engine that uses the same bearing dimensions, such as some Novarossi, O.S, RB, etc (in fact most .21 or higher engines use this front bearing). The bearing dimensions are 7mm inner, 19mm outer and 6mm thick. This bearing is sealed to stop fuel leaking out the front of the engine during use and to avoid dirt getting into the engine.
The Rear Engine Bearing is a Ceramic “Super Speed Series” or “3S” from Ultimate Racing. This bearing is designed to fit the Ultimate M-4R engines, and will also fit any other .21 competition buggy engine that uses the same bearing dimensions like the O.S. MAX RZ-V01b, RZ-V99b, RB Concepts S7/WS7/WS7II, Novarossi N21BF and OPS Engines. The bearing dimensions are 13mm inner, 25mm outer and 6mm thick.
Our Ultimate Ceramic Engine Bearings are a hybrid type, featuring Stainless Steel inner and outer races, with Si3N4 silicone nitride ceramic balls. Ceramic bearings have many advantages over standard steel bearings, such as decreased weight, higher RPM capabilities, increased corrosion and wear resistance, as well as reduced friction and vibration.
The bearings are calibrated and assembled by hand and its tolerance is twice checked by a specific measurement machine.
We recommend using the new Ultimate EFRA 2123 Off-Road Super Strong Pipe Set with Manifold. This high quality aluminium pipe has been developed for competition racing, to provide great throttle control, increase power and high top speeds. With its hard chrome-plated finish, this pipe features precise throttle response in the lower rpm range, combined with smooth and linear performance up to the high rpm range to produce great power characteristics and efficient fuel consumption. The Ultimate EFRA 2123 is a great choice for all current 1/8 off-road engines, and has been IFMAR, EFRA, ROAR, DMC and BRCA approved (EFRA# 2123).
RECOMMENDED GLOW PLUGS
C5TGC: For ambient temperature - 32°F/50°F (0°C/10°C)
C6TGC: For ambient temperature - 50°F/77°F (10°C/25°C)
C7TGC: For ambient temperature - 77°F/104°F (25°C/40°C)
Displacement: 3,49 cc
R.P.M. (max power): 34.500
Practical Range: 7.000-36.500
Bore x Stroke: 16,42x16,42
Sleeve: 4 ports
Rear Ball Bearing: ceramic 13mm inner, 25mm outer and 6mm thick.
Front Ball Bearing: ceramic 7mm inner, 19mm outer and 6mm thick.
Crankshaft: 13 mm - turbo - tuned
Carburetor: plastic - 9 mm - reverse
Glowplug: Turbo (C6TGC)
Exhaust Position: rear
Fuel type: 25% nitro