Important Safety Information Most accidents involving product operation, maintenance and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary train- ing, skills and tools to perform these functions properly.
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TO THE CUSTOMERS This operation and maintenance manual is designed to serve as a reference for DHI's customers and distributors who wish to gain basic product knowledge on DHI's DB33 Diesel engine. To maintain the engine in optimum condition and retain maximum performance for a long time, CORRECT OPERATION and PROPER MAINTENANCE are essential.
CONTENTS CONTENTS CONTENTS CONTENTS 1. GENERAL INFORMATIONS 1. GENERAL INFORMATIONS 1. GENERAL INFORMATIONS 1. GENERAL INFORMATIONS 1.1. General Repair Instructions 1.1. General Repair Instructions 1.1. General Repair Instructions 1.1. General Repair Instructions 1.4. Major Parts Fixing Bolts 1.4. Major Parts Fixing Bolts 1.4.
1. GENERAL INFORMATION 1.1. General Repair Instructions 1. For safety, park the truck on even ground or work station and fix the wheels using wedges and hand brake during operation. 2. Before performing service operations, disconnect the grounding cable from the battery to reduce the chance of cable damage and burning due to short-circuiting.
1.2. Engine Specifications Engine Model DB 33A Items Engine type Water-cooled, 4 cycle in-line, overhead valve type Combustion chamber type Direct injection type Cylinder liner type Dry type, casting liner Timing gear system Gear drive type No. of piston ring Compression ring 2, oil ring 1 No.
1.3. Torque Specifications Standards bolts ¡ The torque values given in the following table should be applied where a particular torque is not specified. (Unit : kgƒU m) Bolt identification Bolt diameter¡¿ pitch Low carbon steel High carbon steel Alloy steel 0.4-0.8 0.5-1.0 6¡¿...
1.4. Major Parts Fixing Bolts Cylinder head and block ¡ (unit : kgƒU m) 18.0 lb¡⁄ft 15.2 lb¡⁄ft 72.32 lb¡⁄ ft 10.0 11.5 83.17 lb¡⁄ft 38.33 lb¡⁄ft...
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Intake and exhaust manifold ¡ (unit : kgƒU m) 15.2 lb¡⁄ft 15.2 lb¡⁄ft...
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Cylinder block and others ¡ (unit : kgƒU m) 13.7 99.1 lb¡⁄ ft Lubricate with engine oil 15.2 lb¡⁄ft 18.8 lb¡⁄ft 57.0 lb¡⁄ ft 18.8 lb¡⁄ ft Lubricate with engine oil...
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Cylinder block and others ¡ (unit : kgƒU m) 18.8 lb¡⁄ ft 18.8 lb¡⁄ft 38.3 lb¡⁄ ft 18.8 lb¡⁄ft 38.3 lb¡⁄ft...
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Crankshaft and camshaft ¡ (unit : kgƒU m) 44.0 318 lb¡⁄ft 9.75¡ 0.25 70.5 ¡ 1.8 lb¡⁄ft 12¡ 0.25 86.8 ¡ 1.8 lb¡⁄ ft 16.0 115.7 lb¡⁄ft 39.8 lb¡⁄ ft 18.1 lb¡⁄ ft 16.0 115.7 lb¡⁄ ft...
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Thermostat and housing ¡ (unit : kgƒU m) 10.5 lb¡⁄ft 25.1 lb¡⁄ft...
1.5. Engine Repair Kit Part No. 1¡›25 : Engine disassembly components Part No. 1, 3, 21, 22, 25 : Engine top disassembly components 1. Gasket : Cylinder head 14. Gasket : Oil pan and body 2. Gasket : Cylinder head cover and bolt 15.
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1.6. Repair 1.6.1. Cylinder Head Bolt Tighten the cylinder head bolts in sequence as shown in the figure. 11.5 Torque(kgƒU m) ( 83.2 lb¡⁄ft) Front 1.6.2 Valve Clearance Adjust the valve clearance in the following manner using a feeler gauge. Standard(in cold) Intake and exhaust (mm) (.016 in)
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Adjust the clearances of valves marked with an arrow Rocker arm screw lock nut torque (kgƒU m) (18.1 lb¡⁄ft) After adjusting the valve clearances referring to the drawing, turn the crankshaft one full turn in the rotative direction and align the TDC mark with the pointer, then adjust the remaining valve clearances.
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Injection timing adjustment 1. Adjust fuel injection timing with crank pulley notched line and timing pointer. Adjust the timing pointer with the marking on the pulley. Disconnect the inj. pipes (4pieces) from I/P 2. Remove 2 fixing bolts of timing flange and injection pump.
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4. Install the No. 1 injection pipe and tighten to specified torque. 3¡›3.5 Injection pipe nut torque (kgƒU m) (21.7~25.3 lb¡⁄ ft) Do not overtighten the delivery valve holder. It will distort the injection pump body shape and adversery affect control rack operation. 1.6.4.
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Detergent Wash the element in warm water and nonsudsing ¡ household detergent. Rinse the element with clean water ¡ Dry it thoroughly with natural air or electric fan. ¡ Don't use a flame or compressed air for drying. It damages the element. Checking element Insert a light inside the clean and dry element and ¡...
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1.6.8. Fuel System Injection nozzle Correct Incorrect Incorrect Check the spraying condition and injection starting pressure. Injection starting pressure (kg/cm (3.128 psi) Adjustment Adjust the injection starting pressure with the adjusting screw using a nozzle tester. 1.6.9. Fan Belt Fan pulley (mm) Depress here Specified belt deflection...
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2. Engine Assembly 2.1. General Description...
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2.2. Disassembly 2.2.1. External Parts (A) <Disassembly steps> 1. Breather hose 7. Oil pan 2. Exhaust manifold 8. Cylinder head cover 3. Oil guide tube and level gauge 9. Rubber hose 4. Starter 10. Water pump 5. Cooling fan belt 11.
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Important operations Exhaust manifold assembly(2) ¡ Loosen the manifold fixing bolts in sequence of figure's shown. Cylinder head cover(8) ¡ Loosen the head cover bolts in sequence of figure's shown...
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Important operations Engine control cable. ¡ Disassemble the engine control cable. Injection nozzle(2) ¡ Avoid damaging the nozzle tips or other parts during disassembly. Injection pump assembly(7) ¡ When disassembving the injection pump, cap or tape the delivery valve holder to avoid dirt entry.
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2.2.3. Internal Parts Major Components ¡ <Disassembly steps> 1. Rocker arm shaft assembly 12. Crankshaft pulley 2. Push rod 13. Gear case cover 3. Cylinder head assembly 14. Idle gear 4. Cylinder head gasket 15. Camshaft assembly 5. Fly wheel 16.
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Important operations ‹ Rocker arm shaft assembly (1) ¡ ¡ Loosen the rocker arm shaft assembly bolts a little at a time in numerical sequence as shown in the figure. ‹ Cylinder head assembly (3) ¡ ¡ Loosen the cylinder head bolts a little at a time in the numerical sequence as shown in the figure.
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‹ Crankshaft front nut and washer (11) ¡ ¡ Wrench : 41 mm Wrench ‹ Idle gear (14) ¡ ¡ Measure the following points before disassembly. Idle gear end play. (mm) Standard Limit 0.058¡› 0.115 (.002~0.0045 in) (.0078 in) Feeler gauge Backlash (mm) Standard...
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‹ Thrust bearing (18) ¡ ¡ Remove the thrust bearing with steel wire. Wire ‹ Tappet (21) ¡ ¡ Mark the cylinder No Remove the tappets and mark the cylinder number each tappet. (Be careful against the damages) Exhaust Intake 2.2.4.
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Cylinder head assembly ¡ <Disassembly steps> 3. Valve 1. Spring retainer and valve cotter 4. Valve stem oil seal 2. Spring and spring seat Important operations Mark the cylinder No. each component when it disassembles. Valve spring ¡ Valve ¡ Valve seat ¡...
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Piston and connecting-rod assembly ¡ <Disassembly steps> 3. Piston pin and connecting-rod 1. Piston ring 4. Piston 2. Snap ring Important operations Mark the cylinder No. each component when it disassembles. Piston ring ¡ Piston ¡ Piston pin ¡ Connecting-rod ¡...
‹ Piston ring (1) ¡ ¡ Remove the piston rings ‹ Snap ring (2) ¡ ¡ Remove the piston pin snap ring ‹ Piston pin and connecting-rod (3) ¡ ¡ Pull out the piston pin with brass bar 2.3. Inspection and Repair Make the necessary adjustments, repairs and replacements if excessive wear or damage is discovered during inspection.
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Lower face warpage and height (mm) Standard Limit 0.05 or less Warpage (.008 in) (.002 in) Thickness 89.75 89.95¡›90.05 (reference) (3.53 in) (3.54~3.55 in) 2.3.2. Valve, Valve Guide and Valve Seat Insert Valve contact width (mm) Standard Limit (.059 in) (.079 in) Contact width Valve depression...
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2.3.3. Valve Spring Valve Spring Free Length Use a vernier caliper to measure the valve spring free length. If the measured value is less than the specified limit, the valve spring must be replaced. Limit Standard Remark Exhaust and Intake 49.0 mm 47.0 mm Valve Spring Free...
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Diameter (mm) Standard Limit 27.97¡›27.98 (1.10 in) (1.09 in) Micrometer Clearance between the tappet and cylinder body (mm) Dial indicator Standard Limit 0.02¡›0.054 (.0008~.002 in) (.004 in) 2.3.5. Push Rod Run-out 0.03 Limit (mm) (.0012 in) ‹ Use a feeler gauge to measure the push rod run-out ¡...
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Rocker arm bushing (mm) Standard Limit 19.01~19.03 19.05 (.748¡›.749 in) (.75 in) Clearance between rocker arm shaft and bushing (mm) Standard Limit 0.01¡› 0.05 (.0004¡›.0020 in) (.0079 in) 2.3.7. Camshaft Assembly Inspect all disassembled parts for wear, damage and any abnormalities. ‹...
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Run-out (mm) 56.00¡›56.03 Standard Camshaft bearing (2.205~2.206 in) Clearance between camshaft journal and body (mm) Standard Limit 0.03¡›0.09 0.15 (.001~.004 in) (.006 in) Camshaft bearing replacement Remover, installer Remover, installer Align the camshaft oil holes with the cylinder body oil ports.
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Cam gear and thrust plate replacement Camshaft gear Disassembly : Gear puller Install : Use a bench press and a hammer 16.0 Torque (kgƒU m) (115.7 lb¡⁄ ft) Cam lobe height (mm) Standard Limit 47.7 46.5 Cam lobe height (C) (1.88 in) (1.83 in) 56.0...
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2.3.9. Cylinder Block and Liner Cylinder bore measurement Measuring point : Approx. 20mm bellow from upper face(Maximum wear portion) (mm) Standard Limit 105.00¡›105.04 105.10 For steel liner (4.14 in) (4.13~4.14 in) 105.99¡›106.01 106.10 For cast liner (4.17~4.179 in) (4.18 in) Cylinder liner replacement Angle Disassembly : Removeer...
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Cylinder liner inner diameter (mm) Liner Grade Standard 102.021¡›102.040 (4.016~4.017 in) For steel liner 102.041¡›102.060 (4.017~4.018 in) 102.021¡›102.030 (4.016~4.017 in) For cast liner 102.031¡›102.042 (4.017 in) 2.3.10. Piston, Piston Pin and Piston Ring Piston outer diameter (mm) Piston grade Standard 101.955¡›101.975 (4.014~4.015 in) For steel liner...
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Piston pin outside diameter (mm) Standard Limit 35.000¡›35.005 34.95 (1.377~1.378 in) (1.376 in) Piston pin and piston clearance (mm) 0.005 Limit (mm) (.0002 in) 2.3.11. Connecting Rod and Bearing Connecting rod aligmment (parallelism) Alignment (per length of 100mm (3.94 in)) (mm) Standard Limit...
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Bushing replacement Removal : Use a brass bar and a bench press Bench press Installation : Use a brass bar and a bench press. The connecting rod busing oil port must be Brass bar aligned with the connecting rod oil port. After new bushing installation, ream the bushing inside diameter with a pin hole grinder or a reamer to fit the piston pin.
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Crankshaft pin outside diameter ¤Œ ¤Ø ¤ 63.932¡›63.944 Standard (mm) (2.517~2.517 in) ¤Ł ¤Ł Use a micrometer to measure the crankshaft pin ¤Œ ¤Ø ¤ outside diameter across points ¤ and ¤Łat the two points ¤Øand ¤Œ . Connecting rod bearing cap reassembly 12¡...
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Crankshaft journal outside diameter I II 75.913¡›75.925 Standard (mm) (2.989 in.) Use a micrometer to measure the crankshaft journal outside diameter across points £ and £ at the two points ¥ ¥– Journal bearing cap reassembly Torque (kgƒU m) (173.6 lb¡⁄ ft) Refer to Inside diameter "Major components disassembly"...
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Crankshaft gear Inspect the crankshaft gear - Before the gear disassembly, check the crank gear backlash. Refer to - If excessive wear of any damage is found through "Major components disassembly" the inspection, replace the crankshaft gear. - Gear backlash. Crankshaft gear replacement Removal : Remover Remover...
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2.3.13. Flywheel and Housing(Rear Oil Seal) ‹ Flywheel thickness (Friction face) (mm) ¡ ¡ Standard Limit 33.4¡› 33.6 32.5 Friction face (1.315~1.323 in) Crankshaft (1.280 in) assembly face Ring gear replacement Removal : Use a brass bar and hammer - Strike around the edges of the ring gear with a hammer and brass bar to remove it.
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2.3.14. Timing Gear Case Cover Oil seal replacement Installation : Installer Installer 2.4. Engine Reassembly 2.4.1. Minor Components ‹ Piston and connecting-rod assembly ¡ ¡ <Disassembly steps> 3. Snap ring 1. Piston 4. Piston ring 2. Piston pin 5. Connecting rod Important operation Piston heater ‹...
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‹ Piston pin and connecting-rod (2) ¡ ¡ Piston head 1. Install the connecting-rod to the piston with setting the marks as illustrated. Front mark 2. Install the piston pin into the piston and the connecting-rod bushing Cylinder numder marked side ‹...
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‹ Cylinder head assembly ¡ ¡ <Disassembly steps> 3. Spring seat and spring 1. Valve stem oil seal 4. Spring retainer and cotter key 2. Valve Important operation ‹ Valve stem oil seal (1) ¡ ¡ Installer Installer Lubricate the oil seals and valve guides and install the oil seals with an installer.
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‹ Spring seat and spring (3) ¡ ¡ Install the valve springs with their painted end(the close pitched end) facing down. Painted portion ‹ Spring retainer and cotter key (4) ¡ ¡ Installer : Spring compressor - Use a spring compressor to push the valve spring into position.
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2.4.2. Internal Parts ‹ Major components ¡ ¡ <Disassembly steps> 13. Idle gear 1. Tappet 14. Timing gear case cover 2. Crankshaft bearing(upper) 15. Crankshaft pulley 3. Crankshaft 16. Crankshaft front nut and washer 4. Thrust bearing 17. Flywheel housing 5.
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Important operation With oil hole Fit correctly and groove ‹ Crankshaft bearing (upper) (2) ¡ ¡ ‹ Crankshaft bearing (lower) (5) ¡ ¡ Center lower half bearing has no oil groove and oil hole while others all have oil groove and oil hole. No oil groove and hole (center lower) ‹...
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‹ Timing gear case (6) ¡ ¡ Torque (kgƒU m) (18.8 lb¡⁄ ft) ‹ Camshaft (7) ¡ ¡ Tighten the thrust plate bolts through the camshaft gear hole. ‹ Torque (kgƒU m) ¡ ¡ Thrust plate bolt (15.2 lb¡⁄ft) Camshaft gear bolt (115.7 lb¡⁄ft) Camshaft gear ‹...
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‹ Oil pump assembly(9) ¡ ¡ Full up the oil pump with engine oil and install the pump to the cylinder body. Oil pump ‹ Oil pump mounting bolts ¡ ¡ Torque (kgƒU m) (27.5 lb¡⁄ ft) ‹ Oil cooler(11) ¡...
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‹ Idle gear(13) ¡ ¡ Use the thrust collar fixing bolt as a guide to install the idler gear shaft. The oil port must be facing the camshaft. Set the timing marks (A,B,C) as shown in the figure. Injection pump gear "B"...
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‹ Cylinder head gasket (20) ¡ ¡ Front top mark The gasket "TOP" mark must be facing up and "FRONT" mark is towards the front of the engine. Front ‹ Cylinder head assembly (21) ¡ ¡ Carefully place the cylinder head on the cylinder body. Lubricate the head bolts and contact face of the cylinder head.
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2.4.3. External parts (A) <Disassembly steps> 1. Breather hose 7. Oil pan 2. Exhaust manifold 8. Cylinder head cover 3. Oil guide tube and level gauge 9. Rubber hose 4. Starter 10. Water pump 5. Cooling fan belt 11. Thermostat housing assembly 6.
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Important operation ‹ Oil pan (1) ¡ ¡ - Apply liquid gasket to the cylinder block and oil pan. - Install oil pan gasket and oil pan. Bolt torque (kgƒU m) (11.6 lb¡⁄ ft) ‹ Cylinder head cover (2) ¡ ¡ Bolt torque (kgƒU m) (15.2 lb¡⁄...
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‹ Cooling fan belt (13) ¡ ¡ Adjust the cooling fan belt tension. Refer to Maintenance for the fan bolt tension adjustment ‹ Starter motor (9) ¡ ¡ Torque (kgƒU m) (62.2 lb¡⁄ ft) ‹ Exhaust manifold (11) ¡ ¡ Carefully install the gasket with the "TOP"...
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2.4.4. Extermal Parts (B) <Disassembly steps> 1. Oil filter and bracket 5. Injection nozzle 6. Injection pipe 2. Oil pipe 3. Intake manifold 7. Engine control lever 4. Glow plug...
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Important operation ‹ Main oil filter and bracket (1) (kgƒUm) ¡ ¡ 'A' bolt torque (38.3 lb¡⁄ ft) ‹ Intake manifold assembly (3) ¡ ¡ Install the gasket with its protruding part facing up. Protruding Part ‹ Glow plug (4) ¡...
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‹ Fuel injection pipe (6) ¡ ¡ Torque (kgƒU m) (21.7 lb¡⁄ ft) Delivery valve holder must be tightened as specified torque. Excessive torque causes leakage at control rack and pipe. Delivery valve 4.0~4.5 Holder torque (kgƒU m) (28.9~32.5 lb¡⁄ ft)
3. Lubricating System 3.1. General Description O/P : Opening pressure O/P warning Full flow filter lamp Start Battery By-pass Oil filter valve warning lamp By-pass O/P 1kg/cm Oil press S/W valve Cylinder body main oil gallery Paper filter cooler O/P 2kg/cm Crank Timing O/P 8kg/cm...
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Inspection and repair Make the necessary adjustments, repairs and part replacements if excessive wear or damage is found through inspection. Visually inspect the disassembled parts for excessive wear and damage. Oil pump cover and oil pump drive gear clearance. 0.18 Limit (mm) (.007 in) Cover and driven gear clearance...
3.4. Oil Cooler Disassembly <Disassembly steps> 3. Spring 1. Element 2. Bolt 4. By-pass valve Inspection and repair Make the necessary adjustments, repairs and part replacements if excessive wear or damage is found through inspection. Reassembly To reassemble follow the disassembly procedures in reverse order.
4. Cooling System 4.1. General Description 4.2. Water Pump Disassembly <Disassembly steps> 1. Cover 3. Center-Fan 5. Shaft bearing and spacer 2. Impeller 4. Snap ring 6. Seal unit, washer and seal...
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Important operation ‹ Impeller (2) ¡ ¡ Removal : Remover ‹ Pulley center (3) ¡ ¡ Remove the pulley center using a bench press and a Bench press bar. Pully center ‹ Snap ring (4) ¡ ¡ Remove the snap ring using a snap ring plier. ‹...
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Inspection and repair Make the necessary adjustments, repairs and part replacements if excessive wear or damage is found through inspection. Bearing replacement Removal ; Use a bench press Assembly Use a bench press to install two bearings with a marked side outward. Marked side outward Reassembly To assemble, follow the disassembly procedures in...
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‹ Snap ring (4) ¡ ¡ Install the snap ring using a snap ring plier. ‹ Pulley center (5) ¡ ¡ Install the pulley center using a bench press. ‹ Impeller (2) ¡ ¡ ƒUInstall the impeller to the shaft using a bench press. Bench press ƒUUse a feeler gauge to measure the clearance between the impeller and the pump body.
5.2. Fuel Filter Inspection and repair Make the necessary adjustments, repairs and part replacements if excessive wear or damage is found through inspection. Reassembly To assemble, follow the disassembly procedures in reverse order. 5.3. Injection Nozzle Disassembly <Disassembly steps> 1. Plunger 4.
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Important operation ‹ Injection nozzle (3) ¡ ¡ Remove the nozzle assembly from the nozzle body. Keep the parts separately to maintain the proper needle valve to body combination. Inspection and repair Make the necessary adjustments, repairs and part replacements if excessive wear or damage is found through inspection.
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Important operation ‹ Injection nozzle (3) ¡ ¡ Align the nozzle dowel pin with the dowel hole in the nozzle holder body. ‹ Retaining nut (2) ¡ ¡ Torque (kgƒU m) ( 43.4~57.9 lb¡⁄ ft) ‹ Adjust shim (7) ¡ ¡ The injection nozzle injection starting pressure can be adjusted after the adjusting shim is installed.
6. Special Tool List Figure Tool name Cylinder head bolt wrench Injection pump Compression gauge adapter Valve spring compressor Valve guide remover and installer Camshaft bearing remover and installer Cylinder remover Cylinder liner remover angle Cylinder liner installer...
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Figure Tool name Crankshaft gear remover Crankshaft gear installer Crankshaft pilot bearing remover Crankshaft rear oil seal installer Crankshaft front oil seal installer Valve stem oil seal installer Piston ring compressor Water pump impeller remover...
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