# Crankshaft main journal diameter (NA8)

Canonical URL: https://miatatorque.com/spec/crankshaft-main-journal-diameter-na8/

Applicability: NA 1994–1997 (BP) — Other years inferred from 1994 factory evidence.

Confidence: fsm

Main journal
Diameter: 49.938—49.956mm {1.9661—1.9667 in}

Always confirm against your factory manual. Match every restriction and follow all stages and procedure notes. Disputed claims must not be automatically resolved. The complete record below preserves every printed unit, source claim and procedure.

```json
{
  "id": "crankshaft-main-journal-diameter-na8",
  "name": "Crankshaft main journal diameter (NA8)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NA",
      "years": [
        1994,
        1997
      ],
      "engines": [
        "BP"
      ],
      "note": "Other years inferred from 1994 factory evidence."
    }
  ],
  "kind": "non-torque",
  "value_text": "Main journal\nDiameter: 49.938—49.956mm {1.9661—1.9667 in}",
  "procedure": {
    "notes": "Standard diameter; measure X and Y directions at two axial points. Regrind below minimum only to factory undersize-bearing requirements."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1994",
      "page": "B–57 (PDF p. 94)",
      "as_printed": "Main journal\nDiameter: 49.938—49.956mm {1.9661—1.9667 in}",
      "verified_years": [
        1994,
        1994
      ],
      "document": {
        "id": "fsm-1994",
        "tier": 1,
        "title": "1994 Mazda MX-5 Miata Workshop Manual",
        "covers": [
          {
            "gen": "NA",
            "years": [
              1994,
              1997
            ],
            "engines": [
              "BP"
            ]
          }
        ],
        "note": "Mazda's base manual for 1994–97; later model years got supplements, which we haven't checked yet."
      }
    }
  ],
  "jobs": [],
  "system": "engine",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/crankshaft-main-journal-diameter-na8/"
}
```