Mazda MX-5 1990 Workshop Manual page 788

TO
TECHNICAL OAT A
A. MEASUREMENTS
Item Measurements
Overall length
mm (in)
3,948 (155.4)
Overall width mm (in) 1,676 (65.9)
Overall height
mm (in) 1,224 (48.2)
Wheelbase mm (in) 2,266 (89.2)
Tread
l
Front
mm (in) 1,410 (55.5)
I
Rear
mm (in) 1,428 (56.2)
B. ENGINE
Item
Engine
86 DOHC
Type
Gasoline, 4-cycle
Cylinder arrangement and number In-line, 4-cylinders
Combustion chamber
Pentroof
Valve system DOHC, belt-driven 16 valves
Bore x Stroke
mm (in) 78.0 x 83.6 (3.07 x 3.29)
Total piston displacement cc (cu in) 1,597 (97.42)
Compression ratio
9.4
Standard 1,324 (13.5, 192)-300
Compression pressure
Minimum
932 (9.5, 135)-300
kPa (kg/cm
2
,
pSi)-rpm
Maximum difference between
196 (2.0, 28)
each cylinder
IN
Open BTDC
5°
Valve timing
Close ABDC
51°
Open BBDC 53°
EX
Close ATDC
15°
Valve clearance
mm (in)
IN
0: Maintenance-free
EX
0: Maintenance-free
Cylinder head
Height mm (in)
133.8-134.0 (5.268-5.276)
Distortion
mm (in) 0.15 (0.006) max.
Grinding mm (in)
0.20 (0.008) max.
Cylinder head-to-HLA clearance
mm (in)
Standard
0.025-0.066 (0.0010-0.0026)
Maximum
0.18 (0.0071)
Valve and valve guide
Valve head diameter
mm (in)
IN
30.9-31.1 (1.217-1.224)
EX
26.1-26.3 (1.028-1.035)
Valve head margin thickness mm (in)
IN 1.0 (0.039)
EX
1.0 (0.039)
Valve face angle
IN
45°
EX
45°
IN
Standard 105.29 (4.1452)
Valve length mm (in)
Minimum 104.79 (4.1256)
Standard 105.39 (4.1492)
EX
Minimum 104.89 (4.1295)
Valve stem diameter mm (in)
IN 5.970-5.985 (0.2350-0.2356)
EX
5.965-5.980 (0.2348-0.2354)
Guide inner diameter mm (in)
6.01-6.03 (0.2366-0.2374)
IN 0.025-0.060 (0.0010-0.0024)
Valve stem-to-guide clearance mm (in)
EX
0.030-0.065 (0.0012-0.0026)
Maximum 0.20 (0.008)
Guide projection (Height "A") mm (in)
IN 16.8-17.4 (0.661-0.685)
EX
16.8-17.4 (0.661-0.685)
Valve seat
Seat angle
IN 45°
EX
45°
TO-2