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Mechanical (H4SO): General Description: Specification

Engine Model 2.5 L
Cylinder arrangement Horizontally opposed, liquid cooled, 4-cylinder, 4-stroke gasoline engine
Valve system mechanism Belt driven, single overhead camshaft, 4 valve/cylinder
Bore x Stroke mm (in) 99.5 x 79.0 (3.92 x 3.11)
Displacement cm3 (cu in) 2, 57 (149.94)
Compression ratio 10.0
Compression pressure (at 200 - 300 rpm) kPa (kg/cm2 , psi) Standard 1, 20 - 1, 75 (10.4 - 13.0, 148 - 185)
Number of piston rings Pressure ring: 2, Oil ring: 1
Intake valve timing Constant Open BTDC 0°
Close ABDC 58°
Low speed Open BTDC 0°
Close ABDC -10°
High speed Open BTDC 14°
Close ABDC 62°
Exhaust valve timing Open BBDC30°
Close ATDC14°
Valve clearance mm (in) Intake 0.20±0.04 (0.0079±0.0016)
Exhaust 0.25±0.04 (0.0098±0.0016)
Idle speed (For CVT model, select lever in "P" or "N" range. For MT model, gear shift lever in neutral position.) rpm No load Standard CVT model: 675±100
MT model: 650±100
A/C ON Standard 700 - 850
Ignition order 1 → 3 → 2 → 4
Ignition timing BTDC/rpm Standard CVT model: 15°±10°/675
MT model: 10°±10°/650
Belt tension adjuster Adjuster rod protrusion amount mm (in) 5.2 - 6.2 (0.205 - 0.244)
Valve rocker arm Clearance between arm and shaft mm (in) Standard 0.020 - 0.054 (0.0008 - 0.0021)
Rocker arm inside diameter mm (in) Standard 22.020 - 22.041 (0.8669 - 0.8678)
Rocker shaft diameter mm (in) Standard 21.987 - 22.000 (0.8656 - 0.8661)
Camshaft Bending limit mm (in) 0.025 (0.00098)
Cam lobe height mm (in) Intake Constant Standard 40.075 - 40.175 (1.5778 - 1.5817)
Low speed Standard 35.496 - 35.596 (1.3975 - 1.4014)
High speed Standard 40.315 - 40.415 (1.5872 - 1.5911)
Exhaust Standard 39.289 - 39.389 (1.5468 - 1.5507)
Cam base circle diameter mm (in) Standard 34.00 (1.3386)
Base circle step of adjacent intake cams (low speed and high speed) mm (in) Standard 0.03 (0.001) or less
Oil clearance mm (in) Standard 0.055 - 0.090 (0.0022 - 0.0035)
Journal O.D. mm (in) Standard 31.928 - 31.945 (1.2570 - 1.2577)
Cylinder head journal I.D. mm (in) Standard 32.000 - 32.018 (1.2598 - 1.2605)
Thrust clearance mm (in) Standard 0.030 - 0.090 (0.0012 - 0.0035)
Cylinder head Warping limit (mating surface with cylinder block) mm (in) 0.035 (0.0014)
Grinding limit mm (in) 0.1 (0.004)
Standard height mm (in) 97.5 (3.84)
Valve seat Seating angle between valve and valve seat 90°
Contacting width between valve and valve seat mm (in) Intake Standard 0.8 - 1.4 (0.03 - 0.055)
Exhaust Standard 1.2 - 1.8 (0.047 - 0.071)
Valve guide Clearance between the valve guide and valve stem mm (in) Intake Standard 0.035 - 0.062 (0.0014 - 0.0024)
Exhaust Standard 0.040 - 0.067 (0.0016 - 0.0026)
Inside diameter mm (in) 6.000 - 6.012 (0.2362 - 0.2367)
Valve stem outer diameters mm (in) Intake 5.950 - 5.965 (0.2343 - 0.2348)
Exhaust 5.945 - 5.960 (0.2341 - 0.2346)
Valve guide protrusion amount mm (in) Intake 20.3 - 20.7 (0.799 - 0.815)
Exhaust 16.8 - 17.2 (0.661 - 0.677)
Valve Head edge thickness mm (in) Intake Standard 0.8 - 1.2 (0.03 - 0.047)
Exhaust Standard 1.0 - 1.4 (0.039 - 0.055)
Overall length mm (in) Intake 120.6 (4.75)
Exhaust 121.7 (4.79)
Valve spring Free length mm (in) 55.2 (2.173)
Tension/spring height N (kgf, lb)/mm (in) Set 235.3 - 270.7 (24 - 27.6, 52.9 - 60.8)/45.0 (1.772)
Lift 578.9 - 639.9 (59.1 - 65.3, 130.3 - 143.9)/34.7 (1.366)
Squareness 2.5°, 2.4 mm (0.094 in) or less
Cylinder block Warping limit (mating surface with cylinder head) mm (in) 0.025 (0.00098)
Grinding limit mm (in) 0.1 (0.004)
Standard height mm (in) 201.0 (7.91)
Cylindricality mm (in) Standard 0.015 (0.0006)
Out-of-roundness mm (in) Standard 0.010 (0.0004)
Clearance between cylinder and piston at 20°C (68°F) mm (in) Standard -0.015 - 0.005 (-0.00059 - 0.00020)
Cylinder inner diameter boring limit (diameter) mm (in) To 100.005 (3.9372)
Piston Piston grade point mm (in) 38.2 (1.504)
Outer diameter mm (in) Standard A 99.510 - 99.520 (3.9177 - 3.9181)
B 99.500 - 99.510 (3.9173 - 3.9177)
0.25 (0.0098) OS 99.750 - 99.770 (3.9272 - 3.9280)
0.50 (0.0197) OS 100.000 - 100.020 (3.9370 - 3.9378)
Piston pin Degree of fit Piston pin must be fitted into position with thumb at 20°C (68°F).
Clearance between piston pin hole and piston pin mm (in) Standard 0.004 - 0.008 (0.0002 - 0.0003)
Piston ring Piston ring gap mm (in) Top ring Standard 0.20 - 0.35 (0.0079 - 0.0138)
Second ring Standard 0.37 - 0.52 (0.0146 - 0.0205)
Oil ring Standard 0.20 - 0.50 (0.0079 - 0.0197)
Clearance between piston ring and piston ring groove mm (in) Top ring Standard 0.040 - 0.080 (0.0016 - 0.0031)
Second ring Standard 0.030 - 0.070 (0.0012 - 0.0028)
Connecting rod and connecting rod bearing Bend or twist per 100 mm (3.94 in) in length mm (in) Limit 0.10 (0.0039)
Thrust clearance mm (in) Standard 0.070 - 0.330 (0.0028 - 0.0130)
Oil clearance mm (in) Standard 0.016 - 0.044 (0.0006 - 0.0017)
Bearing size (Thickness at center) mm (in) Standard 1.492 - 1.501 (0.0587 - 0.0591)
0.03 (0.0012) US 1.510 - 1.513 (0.0594 - 0.0596)
0.05 (0.0020) US 1.520 - 1.523 (0.0598 - 0.0600)
0.25 (0.0098) US 1.620 - 1.623 (0.0638 - 0.0639)
Bushing of small end Clearance between piston pin and bushing mm (in) Standard 0 - 0.022 (0 - 0.0009)
Crankshaft and crankshaft bearing Bending limit mm (in) 0.035 (0.0014)
Crank pin Out-of-roundness mm (in) Standard 0.003 (0.0001)
Cylindricality mm (in) Standard 0.004 (0.0002)
Grinding limit (dia.) mm (in) To 51.750 (2.0374)
Crank journal Out-of-roundness mm (in) Standard 0.005 (0.0002)
Cylindricality mm (in) Standard 0.006 (0.0002)
Grinding limit (dia.) mm (in) To 59.758 (2.3527)
Crank pin outer diameter mm (in) Standard 51.984 - 52.000 (2.0466 - 2.0472)
0.03 (0.0012) US 51.954 - 51.970 (2.0454 - 2.0461)
0.05 (0.0020) US 51.934 - 51.950 (2.0446 - 2.0453)
0.25 (0.0098) US 51.734 - 51.750 (2.0368 - 2.0374)
Crank journal outer diameter mm (in) Standard 59.992 - 60.008 (2.3619 - 2.3625)
0.03 (0.0012) US 59.962 - 59.978 (2.3607 - 2.3613)
0.05 (0.0020) US 59.942 - 59.958 (2.3599 - 2.3605)
0.25 (0.0098) US 59.742 - 59.758 (2.3520 - 2.3527)
Bearing size (Thickness at center) mm (in) #1, #3 Standard 1.998 - 2.011 (0.0787 - 0.0792)
0.03 (0.0012) US 2.017 - 2.020 (0.0794 - 0.0795)
0.05 (0.0020) US 2.027 - 2.030 (0.0798 - 0.0799)
0.25 (0.0098) US 2.127 - 2.130 (0.0837 - 0.0839)
#2, #4, #5 Standard 2.000 - 2.013 (0.0787 - 0.0793)
0.03 (0.0012) US 2.019 - 2.022 (0.0795 - 0.0796)
0.05 (0.0020) US 2.029 - 2.032 (0.0799 - 0.0800)
0.25 (0.0098) US 2.129 - 2.132 (0.0838 - 0.0839)
Thrust clearance mm (in) Standard 0.030 - 0.115 (0.0012 - 0.0045)
Oil clearance mm (in) Standard 0.010 - 0.030 (0.0004 - 0.0012)
NOTE: US: Undersize OS: Oversize