CUMMINS ONAN B43G B48G Series Engine Workshop Manual

Service Manual -.. _-- .- - 6 I 45 965-0757 WE (Spec A-D) WG (SF A-D) B48G (Spec A-G) 6-88 Prmlsd in USA

Safety Precautions It is recommended that you read your engine manual and become thoroughly acquainted with your equipment before you start the engine. This symbol if used warns of imme- diate hazards which will result in severe personal injury or death. This symbol refers to 8 hazard or [AWARNING! unsafe practice which can result in severe personal injury or death. This symbol refers to a hazard or unsafe practice which can result in ' personal injury or product or properiy damage. Fuels, electrical equipment, batteries, exhaust gases and moving parts present potential hazards that can result in serious, personal injury. Take care in following these recommended procedures. All local,state and federal codes should be consulted and complied with. This engine Is not designed or in- @@ ! @ tended for use in any type of aircraft. Use of this engine in aircraft can result in engine failure and causes serious personal injury or death. General 0 Provideappropriate fire extinguishers and install them in convenient locations. Use an extinguisher rated ABC by NFPA. 0 Make sure that all fasteners on theenginearesecureand accurately torqued. Keep guards in position over fans, driving belts, etc. 0 If it is necessary to make adjustments while the engine is running,use extreme cautionwhen close to hotexhausts, moving parts, etc. ProtectAgainst Moving Parts 0 Do not wear loose clothing in the vicinity of moving parts, such as Pi0 shafts, flywheels, blowers, couplings, fans, belts, etc. 0 Keep your hands away from moving parts. Batteries Before starting work on the engine, disconnect batteries to prevent inadvertent starting of the engine. DO NOT SMOKE while servicing batteries. Lead acid batteries give off a highly explosive hydrogen gas which can be ignited by flame, electrical arcing or by smoking. Verify battery polarity before connecting battery cables. Connect negative cable last Fuel System b DO NOT fill fuel tanks while engine is running. DO NOT smoke or use an open flame in the vicinity of the engine or fuel tank. Internalcombustion engine fuels are highly flammable. Fuel lines must be of steel piping, adequately secured, and free from leaks. Piping at the engine should be approved flexible line. Do not use copper piping for flexible lines as copper will work harden and become brittle enough to break. Be sure all fuel supplies have a positive shutoff valve. ' Exhaust System 0 Exhaust products of any internal combustion engine are toxic and can cause injury, or death if inhaled. All engine applications, especially those within a confined area, should be equipped with an exhaust system to discharge gases to the outside atmosphere. 0 Do not use exhaust gases to heat a compartment. 0 Make sure that your exhaust system is free of leaks. Ensure that exhaust manifolds are secure and are not warped by bolts unevenly torqued. Exhaust Gas is Deadly! Exhaust gases contain carbon monoxide, a poisonous gas that can cause unconsciousnessand death. It is an odorless and colorless gas formed during combustion of hydrocarbon fuels. Symptoms of carbon monoxide poisoning are: 0 Dizziness 0 Vomiting 0 Headache 0 Muscular Twitching 0 Weakness .and Sleepiness 0 Throbbing in Temples If you experienceany of these symptoms, get out into fresh air immediately, shut down the unit and do not use until it has been inspected. The best protection against carbon monoxide inhalation is proper installation and regular, frequent inspections of the complete exhaust system. If you noticea change in the sound or appearance of exhaust system, shut the unit down immediately and have it inspected and repaired at once by a competent mechanic. Cooling System a 0 Coolantsunder pressure havea higher boilingpoint than water. DO NOT open a radiator pressure cap when coolant temperature is above 212OF (lOO°C) or while engine is running. Keep the Unit and Surrounding Area Clean 0 Make sure that oily rags are not lefl on or near the engine 0 Remove all unnecessary grease and oil from the unit. Accumulated grease and oil can cause overheating and subsequent engine damage and present a potential fire hazard. E-6

Table of Contents TITLE PAGE General Information ................................................. 1-1 Specifications ...................................................... 2-1 Dimensions and Clearances .......................................... 3-1 Assembly Torques and Special Tools ................................. 4-1 Engine Troubleshooting ............................................. 5-1 Oil System .......................................................... 6-1 Fuel System ........................................................ 7-1 Ignition and Battery Charging ........................................ 8-1 Starting System ..................................................... 9-1 Engine Disassembly ................................................ 10-1 I AWARNING 1 EXHAUST GAS IS DEADLY! Exhaust gases from all fuels (including diesel, gasoline, liquid prop ne, natural gas) contain carbon monoxide, an odorless and colorless gas. Carbon monoxide is poisonous and can cause unconsciousness and death. Symptoms of carbon monoxide poisoning can include: 0 Dizziness 0 Nausea Muscular Twitching 0 Headache 0 Vomiting Weakness and Sleepiness Throbbing in Temples 0 Inabirity to Think Coherently IF YOU ORANYONE ELSE EXPERIENCEANY OF THESE SYMPTOMS, GET OUT INTO THE FRESH AIR IMMEDIATELY. If symptoms persist, seek medical atfention. Shut down the unit and do not operate untilit has been inspected and repaired. Protection against carbon monoxide inhalation includes proper installation, ventilation and regular, frequent visual and audible inspections of the complete exhaust system. i

General Information INTRODUCTION This manual deals with specific mechanical and electrical information needed by engine mechanics for troubleshooting, servicing, repairing,or overhaulingthe engine. . * Usethe separatePARTS MANUALfor parts identification and for establishingtheir proper locationon assemblies. The PARTS MANUAL contains detailed exploded views of each assembly and the individual piece part numbers and their proper names for ordering replacementparts. The illustrations and procedures presented in each section apply to the engines listed on the cover. The flywheel-blower end of the engine is the front end so right and leftsides are determined by viewing the engine from the front. The No. 1 cylinder is on the left, No. 2 cylinder is on the right. If a major repair or an overhaul is necessary, acompetent mechanic should either do the job or supervise and check the work of the mechanic assigned to the job to ensure that all dimensions, clearances and torque values are within the specified tolerances. Use the table of contents for a quick reference to the separate engine system sections. The troubleshooting guide is provided as a quick reference for locating and correcting engine trouble. The wiring diagram shows how the electrical components are interconnected. The disassembly section contains major overhaul procedures for step by step removal, disassembly, inspection, repair, and assembly of the engine components. Use only Genuine Onan replacement parts to ensure quality and the best possible repair and overhaul results. When ordering parts, always use the complete model and spec number as well as the serial number shown on the nameplate. ENGINE MODEL REFERENCE Identify your model by referring to the model and specification (spec letter) as shown on the unit nameplate. Always use these numbers and the engine serial number when making reference to your engine. How to interpret MODEL and SPEC NO. B 48 G G A 0201 1 D TTTTTT TT 1 2 3 4 5 6 7 8 IAWARNING i 1. Factory code for general identification of basic engine series. 2. Cubic inch displacement. 3. Engine duty cycle. 4. Fuel required (G=gasoline). 5. Cooling system description (A=air-cooling-pressure). 6. BHP rating. 7. Factory code for designated optional equipment, if 8. Specification (spec letter) which advances with any. factory production modifications. INCORRECT SERVICE OR REPLACEMENT OF PARTS CAN RESULT IN SEVERE PERSONAL INJURY AND/OR EQUIPMENT DAMAGE. SERVICE PERSONNEL MUST BE QUALlFlED TO PERFORM ELECTRICAL AND/OR MECHANICAL SERVICE. 1-1

Specifications This manual contains SI metric equivalents that follow immediately in parentheses after the U.S. customary units of measure. UNIT OF SERIES SPECIFICATION MEASURE B43E 8436 B48G Number of Cylinders 2 2 2 Bore in 3.250 3.250 3.250 (mm) (82.55) (82.55) (82.55) Stroke in 2.620 2.620 2.875 (mm) (66.55) (66.55) (73.00) (cm3) (71 0) (71 0) (782) Compression Ratio 6.2 to 1 6.5 to 1 7.0 to 1 Rated Speed (Maximum) RPM 3600 3600 3600 Power at BHP 16 18 20 Rated Speed (kW) (1 1.9) (13.4) (1 4.9) Oil Capacity Qts 1.5 1.5 1.5 Displacement cu in 43.3 43.3 47.7 Without Filter (I i tre) (1.4) (1 -4) (1 -4) Oil Filter Capacity Qts .3 .3 .3 (litre) (-3) (*3) (-3) Crankshaft Rotation Valve Clearance (Cold) (viewed from flywheel) Clockwise Clockwise Clockwise Intake in .005 .005 .005 Exhaust in .013 .013 .013 Spark Plug Gap in .025 .025 .025 (rnm) (.64) (.64) (.64) Breaker Point Gap - Static (Full Separation and Engine Cold) in .016 .016 .020 (mm) (.41) (-41 ) (-53) (mm) (-1 3) (-1 3) (.13) (mm) (.33) (.33) (.33) Spec A & B Begin Spec C in .016 Ignition Timing Spec A & B Begin Spec C BTC 16" 16" 20" BTC 16" Cylinder Compression psi 75 to 115 75 to 115 75 to 115 (kPa) 517 to 793 517 to 793 517 to 793 2-1

Dimensions and Clearances All clearancesgiven at roomtemperature of 70°F. (21 "C). All dimensions in inches(approximate millimetredimensions in parentheses) unless otherwise specified. a DESCRIPTION . MINIMUM Inches CYLINDER BLOCK Cylinder Bore Honed Diameter ................................... Maximum Allowable 3.2490 Taper ......................................................... Out-of-Round ................................................. Main Bearing Inside Diameter (Without bearing) ................... Main Bearing Inside Diameter (Installed) .......................... Camshaft Bearing Bore (Bearing installed) ........................ 2.187 2.0015 1.3760 CRANKSHAFT Main Bearing Journal Diameter.. ................................. Main Bearing Clearance.. ........................................ 0.0025 Connecting Rod Journal Diameter.. .............................. Crankshaft End Play.. ........................................... 0.006 1.9992 1.6252 CONNECTING ROD Large Bore Diameter (Rod bolts properly torqued) ................. Bearing to Crankshaft Clearance 1.6280 0.0020 0.6879 Aluminum Rod ................................................ 0.0020 Connecting Rod Side Clearance.. ................................ Piston Pin Bushing Bore (Finished bore) .......................... CAMSHAFT Bearing Journal Diameter.. ...................................... 1.3740 Bearing Clearance.. ............................................. 0.0015 End Play. ....................................................... 0.0030 Camshaft Lift B43G, 8486 ................................................... B43E ......................................................... PISTON Clearance in Cylinder Piston Pin Bore.. ................................................ 0.68774 Ring Groove Width Measure 90" to pin 1.187 inch below top of piston ............... Top 1 Compression Ring.. ..................................... 0.0033 0.080 (mm) (82.53) (55.55) (50.84) (34.95) (50.78) (0.064) (41.28) (0.15) (41.35) (0.051) (17.47) (0.051) (34.90) (0.038) (0.076) 0.300 0.258 (0.084) (1 7.47) (2.032) (2.0321 MAXIMUM Inches 3.2500 0.005 0.003 2.188 2.0040 1.3770 2.0000 0.0038 1.6260 0.012 1.6285 0.0160 0.6882 0.0033 1.3745 0.0030 (7.62) (6.55) 0.0053 0.68814 0.081 0.081 (mm) (82.55) (0.1 3) (0.08) (55.58) (50.90) (34.98) (50.80) (0.097) (41.30) (0.30) (41 -36) (0.406) (1 7.48) (0.084) (34.91 ) (0.076 (0.135) (17.48) (2.057) 12.057) - No. 2 Compression Ring. ...................................... No. 3 Oil Control Ring ......................................... 0.188 i4.775j 0.189 i4.801 j 0.080 3- 1

DESCRIPTION MINIMUM MAXIMUM Inches (mm) Inches (mm) PISTON PIN Clearance in Piston .............................................. Clearance in Connecting Rod Aluminum Rod ................................................ Diameter ........................................................ PISTON RINGS Clearance Ring End Gap in Cylinder ........................................ Top Groove ................................................... INTAKE VALVE Stem Diameter .................................................. Clearance (Stem to Guide) ....................................... Valve Face Angle ................................................ INTAKE VALVE SEAT Seat Bore Diameter ............................................. Seat Outside Diameter ........................................... Valve Seat Width ................................................ Valve Seat Angle ................................................ EXHAUST VALVE Stem Diameter .................................................. Clearance (Stem to Guide) ....................................... Valve Face Angle ................................................ EXHAUST VALVE SEAT Seat Bore Diameter .............................................. Seat Outside Diameter ........................................... Valve Seat Width ................................................ Valve Seat Angle ................................................ VALVE GUIDE Inside Diameter ................................................. TAPPET Body Diameter .................................................. Bore Diameter ................................................... Clearance in Bore ............................................... VALVE SPRINGS INTAKE AND EXHAUST Valve Spring Length Valve Spring Free Length (Approx.) .............................. Valve Open .................................................... Valve Closed .................................................. Spring Load @ I 1.375 inch (Valve Closed) .......................... Spring Load @ 1.125 inch (Valve Open) ........................... GEAR BACKLASH Timing Gear ..................................................... Oil Pump Gear .................................................. GOVERNOR Dashpot to Governor Arm Bracket ................................ 0.00004 (0.001 0) 0.00064 (0.01 62) c 0.0002 (0.005) 0.0007 (0.018) 0.6875 (17.46) 0.6877 (17.47) 0.003 (0.076) 0.008 (0.203) 0.010 (0.254) 0.020 (0.508) 0.3425 (8.70) 0.3430 (8.71) 0.0010 (0.025) 0.0025 (0.064) 44" 1.4395 (36.56) 1.4405 (36.59) 1.443 (36.65) 1.444 (36.67) 0.031 (0.787) 0.047 (1.194) 45" 0.3410 (8.661) 0.3415 (8.674) 0.0025 (0.064) 0.040 (0.102) 44" 1.189 (30.20) 1.190 (30.23) 1.192 (30.28) 1.193 (30.30) 0.031 (0.787) 0.047 (1.194) 45O 0.344 (8.74) 0.346 (8.79) 0.7475 (18.99) 0.7480 (19.00) 0.7505 (1 9.06) 0.751 5 (1 9.09) 0.0015 (0.038) 0.003 (0.076) 1.662 (42.21 ) 1.1 25 (28.58) 1.375 (34.93) 38 Ib . (17 kg) 42 Ib . (19 kg) 71 Ib . (32 kg) 79 Ib . (36 kg) 0.001 (0.025) 0.006 (0.152) 0.002 (0.051) 0.005 (0.127) 0.040 (1.02) 0.060 (1.52) 3-2

CUMMINS ONAN B43G B48G Series Engine Workshop Manual

You're Reading a Preview

Recently Viewed