Part Number: 20007783 Applications: Mitsubishi 4B11 EVO X (2.2L) Disclaimer and Warranty A vehicle modified with Cosworth competition and or racing performance products will not meet the legal requirements for operation on public roads and highways. It is the purchaser s responsibility to check and comply with all local, state and federal laws prior to operating vehicle. Installation and use of performance products may also affect and void warranty and insurance policies. In general, Cosworth Performance Parts carry no warranty. Cosworth, LLC and Cosworth Ltd. shall not be liable for direct, indirect, incidental or consequential damage or injury to persons or property that might be claimed as a result from the installation, improper installation, and failure of part including claims for delay, loss of profits or labor. There are no warranties expressed or implied. 1. This Page Index 2. General Installation 3. Before Starting, Block machining, Critical Clearances and Engine Break-in 4. Warranty and General Maintenance 5. Product Disclaimer, Warranty and Bore Notching 6. Squirt Jet Clearancing Parts List 1 20019849 Mitsubishi EVO 4B11T 94mm Billet Crankshaft 1 20007184 Mitsubishi EVO 4B11T Stroker Rod Set 1 20005856 Mitsubishi EVO 4B11T 86mm 9.0:1 Piston Set 1 Mitsubishi EVO 4B11T Rod Bearing Set 1 Mitsubishi EVO 4B11T Main Bearing Set 1 20007178 Mitsubishi EVO 4B11T Thrust Bearing Set 1 20002246 86mm Piston Ring Set
General Installation Congratulations, you are the owner of a Cosworth Mitsubishi 4B11 Stroker Kit. Your stroker kit includes all new crankshaft, connecting rods, pins, piston rings, bearings, etc. All of these parts are painstakingly designed and manufactured by the same engineers and technicians that manufacture Cosworth F1, Champ Car, Formula Atlantic, ALMS, and other professional motorsports engine components. They feature Cosworth forged, lightweight, aluminum pistons, billet 4340 connecting rods, and heavy duty tri-metal bearings to handle the stresses of high horsepower. It is strongly recommended that this stroker kit is installed by an experienced engine builder, tuning shop or mechanic. Your Cosworth stroker kit is intended for light duty motorsports such as club racing, time trials, and track days. If you require a racing engine program and have a significant racing budget, please contact Cosworth for further details on an engine program. The components within your new stroker kit are designed to be used with each other. They have been designed to be used in a factory Mitsubishi 4B11 EVO block casting and cannot be used with other manufacturer s components. Also, your new stroker kit is designed for use with the EVO cylinder block and has not been tested with other variations of the 4B11 engine. Should the components fit into any other 4B11 casting, it is purely coincidental. Cosworth does NOT provide technical support for any other configuration other than the 4B11T EVO cylinder block and head. To ensure optimum cylinder head sealing in high boost applications, Cosworth H-11 head studs are also recommended. Finally, a Cosworth head gasket will also keep the cylinders sealed with increased cylinder pressures of high boost situations. An air to oil cooler using -10AN hoses is strongly recommended to keep oil temperatures below 110 degrees Celcius. Engine bearing life will be shortened with sustained use above this temperature. For high horsepower applications, the factory water to oil cooler is next to useless. For maximum power and reliability, a Cosworth CNC ported cylinder head and camshafts are also suggested. Please take a few minutes to inspect the components for any sign of damage from shipping. Pay special attention to all machined surfaces. If any damage is found, contact your dealer of purchase for any claims. If any damage appears to be caused by shipping damage, file a claim with your shipping carrier.
Before Starting For general disassembly and assembly, refer to factory Mitsubishi service manual for procedures, warnings, and torque specifications. The Cosworth connecting rod bolt stretch is.050-.0065 (.127-.165mm) not to exceed 40lbf-ft (54.2 Nm). We recommend using a light application of assembly lube and/or plenty of 20W-50 mineral engine oil on all machined surfaces during assembly. Block Machining The cylinders must be honed for a final piston to cylinder wall clearance of.003-.0045 (.076-.1143mm) with no more than.0005 (.0127mm) ovality and no more than.0005 (.0127mm) taper on the vertical axis. The gauge point of the piston is at 8.25mm from the bottom of the skirt. The bore should be finish honed using a 325 or 400 grit stone with a 42-45 crosshatch pattern. Critical Clearances All critical clearances between the Cosworth stroker kit components have already been set. However any competent engine builder should always double check these clearances. Wristpin to pin bore clearance:.0002-.0006 (.0050-.0153mm) Rod side clearance:.008-.010 (.2032-.2540mm) Wristpin to pin bush clearance:.001-.0013 (.0254-.0330mm) Rod bearing clearances:.0020-.0026 (.0508-.0661mm) Main bearing clearances:.0020-.0028 (.0508-.0661mm) Compression (top) ring gap:.012-.020 (.3048-.5080mm) 2 nd ring gap:.018-.027 (.4572-.6858mm) Oil ring gap:.008-.028 (.2032-.7112mm) Connecting rod beam to bore/block clearances should be no less than.050 (1.27mm). This is a procedure that your builder will need to execute either by using a hand grinder or a mill. See page 6 for a picture of a finished bore notch. See page 7 for piston to oil squirt jet clearancing. Engine Break-in It is critical that the engine is not started with an excessively rich fuel mixture. An excessively rich mixture will wash away the oil in the cylinders and the rings can potentially never break-in causing excessive oil consumption, crankcase blow-by and lower power output. This damage is permanent. If the engine will be broken in by driving the car, we recommend you keep the engine speed below 4000 rpm. Drive the vehicle at various loads, speeds, and throttle positions while keeping engine speeds below 4000 rpm for approximately 1000 miles (1660 km). The longer the engine is broken in, the better. If breaking your engine in on an engine dynamometer, we recommend the procedure detailed below. This guideline can be used on a chassis dynamometer also, but load readings will differ. Be sure to keep water temperatures below 203 F (95 C) and oil temperatures below 230 F (110 C).
Run at 2000rpm @ 50-60 lbf-ft. (6.9-8.3 kgf-m) load for 20 minutes Run at 3500rpm @ 90-100 lbf-ft. (12.5-13.8 kgf-m) load for 20 minutes Run at 4250rpm @ 100-110 lbf-ft. (13.8-15.2 kgf-m) load for 10 minutes Run at 4250rpm @ 125-135 lbf-ft. (17.3-18.7 kgf-m) load for 5 minutes Run at 5500rpm @ 125-135 lbf-ft. (17.3-18.7 kgf-m) load for 5 minutes Run at 5700 rpm @ WOT for 2 minutes (not to exceed 300 lbf-ft./41.5 kgf-m) During the final break-in stage, the boost should be limited so as not to exceed 300 lbf-ft. (41.5 kgf-m) of torque. Some initial ECU calibration may be required to complete break-in. The engine should be calibrated to achieve an air fuel ratio rich enough for the type of fuel you are using. Consult with a professional tuner for air fuel ratio requirements. Warranty In general, Cosworth competition and/or performance parts carry no warranty. Cosworth LLC and Cosworth Limited shall not be liable for direct, indirect, incidental or consequential damage or injury to persons or property that might be claimed as result from the installation or improper installation and failure of part, including claims for delay, loss of profits or labor. There are no warranties expressed or implied. Disclaimer and Warranty A vehicle modified with Cosworth competition and or racing performance products will not meet the legal requirements for operation on public roads and highways. It is the purchaser s responsibility to check and comply with all local, state and federal laws prior to operating vehicle. Installation and use of performance products may also affect and void warranty and insurance policies. In general, Cosworth Performance Parts carry no warranty. Cosworth, LLC and Cosworth Ltd. shall not be liable for direct, indirect, incidental or consequential damage or injury to persons or property that might be claimed as a result from the installation, improper installation, and failure of part including claims for delay, loss of profits or labor. There are no warranties expressed or implied. General Maintenance Your new engine should be maintained more often than a factory engine. Obviously, it is dependent upon how the engine is used, but the harder you use the engine, the more maintenance is required. Follow the guidelines below: Immediately after break-in, refill with a high quality 100% synthetic 15W-50 engine oil We recommend using a genuine MItsubishi oil filter. We recommend use NGK Racing Iridium spark plugs, heat range 8 or colder. Use a Cosworth low temp thermostat and lower the fan actuation temperatures in the ECU to match. Do NOT remove thermostat from cooling system. A racing radiator may be required in hotter climates.
Product Disclaimer Your new engine will be substantially stronger than a factory Mitsubishi engine if built properly. However, pre-ignition and detonation will destroy the strongest of engines. During the engine calibration procedure pay attention to knock levels very carefully. Always use the fuel recommended by your tuner and consult your tuner before making any changes to your engine configuration. A vehicle modified with Cosworth competition and/or racing performance products will not meet the legal requirement for operation on public roads and highways. It is the purchaser s responsibility to check and comply with all local, state, and federal laws prior to operation vehicle. Installation and use of performance products may also affect and/or void vehicle warranty and insurance policy. Warranty In general, Cosworth competition and/or performance parts carry no warranty. Cosworth LLC and Cosworth Limited shall not be liable for direct, indirect, incidental or consequential damage or injury to persons or property that might be claimed as result from the installation or improper installation and failure of part, including claims for delay, loss of profits or labor. There are no warranties expressed or implied. Bore Notching The image belows shows how the bottom of the bores must be notched for rod clearance. This can be performed by hand using a die grinder and carbide bit or using a mill.
DUE TO THE DESIGN REQUIREMENTS OF THE 4B11T COSWORTH FORGED PISTON, THE PISTON COOLER JET REQUIRES MODIFICATION BY A PROFESSIONAL ENGINE BUILDER. IF OIL JET IS NOT MODIFIED, IT WILL INTERFERE WITH THE STRUT ON THE PISTON AND CAUSE DAMAGE!!!! THE ARROW ILLUSTRATES WHERE THE PISTON COOLER JET WILL INTERFERE. THE ARROW POINTS TO THE DOWEL. THERE ARE MULTIPLE METHODS FOR MODIFYING THE OIL JET: 1. Remove dowel from jet base then rotate and/or bend jet ensuring that there is at least.040" clearance from all other components through the entire 360 of crankshaft rotation. 2. Bend jet carefully ensuring that there is at least.040" clearance from all other components through the entire 360 of crankshaft rotation. 3. Cut and/or bend jet ensuring that there is at least.040" clearance from all other components through the entire 360 of crankshaft rotation. EH 05/12/11 v2.0d