Overview
ISO 17447-1:2022 - Road Vehicles - Glow plugs with conical seating and their cylinder head housing - Part 1: Basic characteristics and dimensions for metal‑sheath‑type glow plugs - defines the main properties, dimensional requirements and mechanical interfaces for metal‑sheath glow plugs used in diesel (compression‑ignition) engines. The standard focuses on thread forms, hexagon sizes, heating‑element geometries, electrical terminals and the matching cylinder head housing dimensions to ensure interchangeability and correct installation.
Key topics and technical requirements
- Scope: Applies to metal‑sheath‑type glow plugs and their cylinder head housings for diesel engines.
- Thread standards and tolerances: Requires compliance with ISO screw‑thread norms (ISO 68‑1, ISO 261, ISO 965‑1, ISO 965‑3). Glow‑plug threads use tolerance class 6g (6e allowed for existing designs); tapped holes use 6H.
- Supported sizes: Detailed dimensions for M14, M12, M10, M9 and M8 glow plugs, including hexagon and body dimensions. (Note: Type M14 is not recommended for new applications.)
- Heating element and tip forms: Defines sheath and tip geometries (cone end, reduced tip, etc.) and overall length ranges to align heating performance and fitment.
- Electrical connections: Pin and blade terminals (types P1–P5) with pin terminal dimensions referenced in Annex A; blade/tab interfaces per ISO 8092 series.
- Cylinder head housing: Matching tapped‑hole and housing dimensions to ensure correct conical seating and sealing.
- Installation torque: Specified tightening torques for unused plugs (with guidance to reduce torque by ~1/3 if threads are lubricated) to prevent overstress and ensure sealing.
- Normative and informative annexes: Annex A (normative) for pin terminals; Annex B (informative) for specific M8 × 1 variants with 10 mm hex.
Practical applications and users
This standard is essential for:
- Glow‑plug manufacturers and tooling engineers - to design parts that meet global dimensional and thread tolerances for interchangeability.
- Engine/OEM designers - to specify correct cylinder head housings and seating to ensure sealing, thermal contact and mechanical reliability.
- Aftermarket and replacement‑parts suppliers - to confirm fitment and compatibility across vehicle platforms.
- Quality assurance and production teams - for inspection criteria and tolerance verification.
- Maintenance and service organizations - to follow recommended torque and connector types during installation and replacement.
Practical benefits include improved parts interchangeability, reduced risk of thread seizure, consistent electrical connection interfaces and clearer supplier‑OEM communication.
Related standards
Keywords: ISO 17447-1, glow plugs, metal‑sheath‑type, diesel engines, cylinder head housing, dimensions, tolerances, threads, installation torque, M10 M12 M14 M9 M8.