# Piston ring end gap — standard and maximum (NA6)

Canonical URL: https://miatatorque.com/spec/piston-ring-end-gap-na6/

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

Confidence: fsm

End gap
Top: 0.15–0.30 mm (0.006–0.012 in)
Second: 0.15–0.30 mm (0.006–0.012 in)
Oil rail: 0.20–0.70 mm (0.008–0.028 in)
Maximum: 1.0 mm (0.039 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": "piston-ring-end-gap-na6",
  "name": "Piston ring end gap — standard and maximum (NA6)",
  "aliases": [],
  "applies_to": [
    {
      "gen": "NA",
      "years": [
        1990,
        1993
      ],
      "engines": [
        "B6"
      ],
      "note": "Other years inferred from 1990 factory evidence."
    }
  ],
  "kind": "non-torque",
  "value_text": "End gap\nTop: 0.15–0.30 mm (0.006–0.012 in)\nSecond: 0.15–0.30 mm (0.006–0.012 in)\nOil rail: 0.20–0.70 mm (0.008–0.028 in)\nMaximum: 1.0 mm (0.039 in)",
  "procedure": {
    "notes": "Insert the ring in the cylinder and square it with a piston at the bottom of ring travel as directed on B–56, then measure end gap with a feeler gauge."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1990",
      "page": "B–57 (PDF p. 84)",
      "as_printed": "End gap\nTop: 0.15—0.30mm (0.006—0.012 in)\nSecond: 0.15—0.30mm (0.006—0.012 in)\nOil rail: 0.20—0.70mm (0.008—0.028 in)\nMaximum: 1.0mm (0.039 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/piston-ring-end-gap-na6/"
}
```