# Valve stem diameter (Mazdaspeed)

Canonical URL: https://miatatorque.com/spec/valve-stem-diameter-msm/

Applicability: NB 2004–2005 (BP-Z3-TURBO) — 2004 factory turbo-engine evidence; 2005 inferred within MSM family.

Confidence: fsm

Standard diameter
IN: 5.970—5.985 mm {0.2351—0.2356 in}
EX: 5.965—5.980 mm {0.2349—0.2354 in}
Minimum diameter
IN: 5.920 mm {0.2331 in}
EX: 5.915 mm {0.2329 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-stem-diameter-msm",
  "name": "Valve stem diameter (Mazdaspeed)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NB",
      "years": [
        2004,
        2005
      ],
      "engines": [
        "BP-Z3-TURBO"
      ],
      "note": "2004 factory turbo-engine evidence; 2005 inferred within MSM family."
    }
  ],
  "kind": "non-torque",
  "value_text": "Standard diameter\nIN: 5.970—5.985 mm {0.2351—0.2356 in}\nEX: 5.965—5.980 mm {0.2349—0.2354 in}\nMinimum diameter\nIN: 5.920 mm {0.2331 in}\nEX: 5.915 mm {0.2329 in}",
  "procedure": {
    "notes": "Measure X and Y at three axial points on each stem."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "workshop-bp-turbo-2004",
      "page": "01–10–19 (PDF p. 31)",
      "as_printed": "Standard diameter\nIN: 5.970—5.985 mm {0.2351—0.2356 in}\nEX: 5.965—5.980 mm {0.2349—0.2354 in}\nMinimum diameter\nIN: 5.920 mm {0.2331 in}\nEX: 5.915 mm {0.2329 in}",
      "verified_years": [
        2004,
        2004
      ],
      "document": {
        "id": "workshop-bp-turbo-2004",
        "tier": 1,
        "title": "2004 Mazda Engine Workshop Manual BP (1.8L), normally aspirated and turbo",
        "part_number": "9999-95-EWBP-04",
        "covers": [
          {
            "gen": "NB",
            "years": [
              2004,
              2004
            ],
            "engines": [
              "BP-Z3-TURBO"
            ],
            "trans": [
              "6MT"
            ]
          }
        ]
      }
    }
  ],
  "jobs": [],
  "system": "engine",
  "component": "inventory-pass-2026-10",
  "componentName": "Service measurements and fasteners",
  "sequence_diagrams": [],
  "url": "https://miatatorque.com/spec/valve-stem-diameter-msm/"
}
```