# Valve guide inner diameter (NA6)

Canonical URL: https://miatatorque.com/spec/valve-guide-inner-diameter-na6/

Applicability: NA 1990–1993 (B6) — Other years inferred from 1990 factory evidence.

Confidence: fsm

Inner diameter
IN: 6.01–6.03 mm (0.2366–0.2374 in)
EX: 6.01–6.03 mm (0.2366–0.2374 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": "valve-guide-inner-diameter-na6",
  "name": "Valve guide inner diameter (NA6)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NA",
      "years": [
        1990,
        1993
      ],
      "engines": [
        "B6"
      ],
      "note": "Other years inferred from 1990 factory evidence."
    }
  ],
  "kind": "non-torque",
  "value_text": "Inner diameter\nIN: 6.01–6.03 mm (0.2366–0.2374 in)\nEX: 6.01–6.03 mm (0.2366–0.2374 in)",
  "procedure": {
    "notes": "Measure the inner diameter of each valve guide at the factory-indicated points."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1990",
      "page": "B–49 (PDF p. 76)",
      "as_printed": "Inner diameter\nIN: 6.01—6.03mm (0.2366—0.2374 in)\nEX: 6.01—6.03mm (0.2366—0.2374 in)",
      "verified_years": [
        1990,
        1990
      ],
      "document": {
        "id": "fsm-1990",
        "tier": 1,
        "title": "1990 Mazda MX-5 Miata Workshop Manual",
        "part_number": "1193-10-89C",
        "covers": [
          {
            "gen": "NA",
            "years": [
              1990,
              1990
            ],
            "engines": [
              "B6"
            ]
          }
        ],
        "url": "https://archive.org/details/1990-mazda-mx-5-miata-workshop-manual_202411"
      }
    }
  ],
  "jobs": [],
  "system": "engine",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/valve-guide-inner-diameter-na6/"
}
```