# Valve spring out-of-square — maximum (NA6)

Canonical URL: https://miatatorque.com/spec/valve-spring-out-of-square-na6/

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

Confidence: fsm

Out-of-square
IN: 1.68 mm (0.0661 in) max.
EX: 1.69 mm (0.0665 in) max.

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-spring-out-of-square-na6",
  "name": "Valve spring out-of-square — 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": "Out-of-square\nIN: 1.68 mm (0.0661 in) max.\nEX: 1.69 mm (0.0665 in) max.",
  "procedure": {
    "notes": "Check spring squareness on a flat surface; replace if out of specification."
  },
  "confidence": "fsm",
  "sources": [
    {
      "source": "fsm-1990",
      "page": "B–52 (PDF p. 79)",
      "as_printed": "Out-of-square\nIN: 1.68mm (0.0661 in) max.\nEX: 1.69mm (0.0665 in) max.",
      "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-spring-out-of-square-na6/"
}
```