Overview
ISO 17447-2:2015 specifies the basic characteristics and dimensions for ceramic‑sheath‑type glow‑plugs and their cylinder head housings for diesel (compression‑ignition) engines. It is part of the ISO 17447 series covering glow‑plugs with conical seating and provides a single, consolidated reference for design, interchangeability and installation of ceramic‑sheath glow‑plugs.
Key topics and requirements
- Scope: Main properties, design requirements and dimensional data for ceramic‑sheath glow‑plugs, terminals and corresponding cylinder head housings.
- Threads and tolerances:
- Glow‑plug threads: nominal sizes include M10 × 1.25, M10 × 1 and M8 × 1.
- New designs: thread tolerance class 6g; tapped holes in cylinder heads: 6H. Existing designs with 6e are permitted.
- Dimension limits and fundamental deviations for pitch/minor diameters are given in tabulated form.
- Glow‑plug geometry:
- Detailed body, heating‑element (types H1, H2) and terminal geometry referenced in figures and tables.
- Pin terminals P1 and P2 defined (detailed dimensions in Annex A).
- Cylinder head housing: Housing dimensions and tolerances for M10 and M8 types are specified to ensure correct seating and sealing.
- Installation torque:
- Recommended tightening torques are provided (e.g., M10: 10–20 Nm; M8: 9–12 Nm; M4 terminal thread: 0.8–1.5 Nm), with guidance to reduce torque by ~1/3 when threads are lubricated.
- Normative references: Applies ISO screw‑thread standards (ISO 68‑1, ISO 261, ISO 965‑1/3) and geometrical tolerancing (ISO 1101).
Applications and practical value
- Ensures interchangeability of ceramic‑sheath glow‑plugs across manufacturers and engine designs.
- Guides design engineers on correct thread classes, seating and housing dimensions to prevent leakage, seizure and installation damage.
- Supports manufacturers and suppliers in producing components that meet international dimensional tolerances.
- Aids service and maintenance technicians with correct installation torque and terminal compatibility.
- Useful for quality control, procurement specifications and component validation in diesel engine development and aftermarket parts.
Who should use this standard
- Glow‑plug manufacturers and materials engineers
- Internal combustion engine designers and OEMs
- Cylinder head and engine component suppliers
- Automotive test labs, quality assurance and aftermarket service organizations
Related standards
Keywords: ISO 17447-2, glow-plugs, ceramic-sheath, diesel engines, cylinder head housing, M10, M8, thread tolerances, installation torque.