# Exhaust valve clearance — cold (NB1)

Canonical URL: https://miatatorque.com/spec/exhaust-valve-clearance-cold-nb1/

Applicability: NB 1999–2000 (BP-4W) — Other years inferred from 1999 factory evidence.

Confidence: fsm

0.28–0.34 mm

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": "exhaust-valve-clearance-cold-nb1",
  "name": "Exhaust valve clearance — cold (NB1)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NB",
      "years": [
        1999,
        2000
      ],
      "engines": [
        "BP-4W"
      ],
      "note": "Other years inferred from 1999 factory evidence."
    }
  ],
  "kind": "non-torque",
  "value_text": "0.28–0.34 mm",
  "procedure": {
    "notes": "Cold engine only. Use the factory No.1/No.4 compression-TDC inspection positions with clockwise crankshaft rotation; correct clearance using the appropriate adjustment shim. Printed inch range is inconsistent with metric; preserve exact quotation and use printed metric under metric-first policy. Repeated in technical data 01–50–1 (PDF312)."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1999",
      "page": "01–10–3 (PDF p. 198)",
      "as_printed": "Standard [Engine cold]\nEX: 0.28—0.34 mm {0.012—0.013 in}\n(0.31 ± 0.03 mm {0.012 ± 0.0012 in})",
      "verified_years": [
        1999,
        1999
      ],
      "document": {
        "id": "fsm-1999",
        "tier": 1,
        "title": "1999 Mazda MX-5 Miata Workshop Manual",
        "covers": [
          {
            "gen": "NB",
            "years": [
              1999,
              2000
            ],
            "engines": [
              "BP-4W"
            ]
          }
        ],
        "url": "https://www.mellens.net/mazda/Mazda-Miata-1999-2001.pdf"
      }
    }
  ],
  "jobs": [],
  "system": "engine",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/exhaust-valve-clearance-cold-nb1/"
}
```