Updated specs are available.
Crankshaft standard journal diameters and out-of-round (NA6)
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Not yet checked against the factory manual for your car's year. It's verified in the 1990 Mazda MX-5 Miata Workshop Manual; later manuals may differ.
Main journal Diameter: 1.9661–1.9668 in (49.938–49.956 mm) Out-of-round: 0.0020 in (0.05 mm) max. Crankpin journal Diameter: 1.7693–1.7699 in (44.940–44.956 mm) Out-of-round: 0.0020 in (0.05 mm) max.Main journal Diameter: 49.938–49.956 mm (1.9661–1.9668 in) Out-of-round: 0.05 mm (0.0020 in) max. Crankpin journal Diameter: 44.940–44.956 mm (1.7693–1.7699 in) Out-of-round: 0.05 mm (0.0020 in) max.
Factory manualTaken from a Mazda factory workshop manual, with page citation.
Procedure
Measure each journal in X/Y directions at two points. These standard diameters do not specify the crank nose, pulley, keyway or crank-center-bolt torque. Preserve the fillet roll area when grinding.
Applies to
- NA 1990–1993 (B6) — Other years inferred from 1990 factory evidence.
- Verified in: 1990 Mazda MX-5 Miata Workshop Manual
Sources (1)
View 1 source citations
Page B–58 (PDF p. 85) · Printed value & notes
Part no. 1193-10-89CPage B–58 (PDF p. 85)Printed: “Main journal Diameter: 49.938—49.956mm (1.9661—1.9668 in) Out-of-round: 0.05mm (0.0020 in) max. Crankpin journal Diameter: 44.940—44.956mm (1.7693—1.7699 in) Out-of-round: 0.05mm (0.0020 in) max.”
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