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

This document specifies the main properties and dimensions of metal-sheath-type glow plugs, including the terminals, and the dimensions of their cylinder head housings, for use with diesel (compression ignition) engines.

Véhicules routiers — Bougies de préchauffage à fourreau et à siège conique et leur logement dans la culasse — Partie 1: Caractéristiques de base et dimensions des bougies de préchauffage à fourreau de type métallique

General Information

• Status: Published
• Publication Date: 24-Apr-2022
• ICS: 43.060.50 - Electrical and electronic equipment. Control systems
• Technical Committee: ISO/TC 22/SC 32 - Electrical and electronic components and general system aspects
• Drafting Committee: ISO/TC 22/SC 32/WG 1 - Ignition Equipment
• Current Stage: 6060 - International Standard published
• Start Date: 25-Apr-2022
• Completion Date: 25-Apr-2022

Relations

• Revises: ISO 17447-1:2015 - Road Vehicles - Glow-plugs with conical seating and their cylinder head housing - Part 1: Basic characteristics and dimensions for metal-sheath-type glow-plugs
• Effective Date: 23-Jun-2018

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

• ISO 17447 series: Part 2 (ceramic‑sheath‑type), Part 3 (tests and requirements)
• ISO 68‑1, ISO 261, ISO 965‑1, ISO 965‑3 (thread standards)
• ISO 1101, ISO 286‑1 (geometrical/tolerance standards)
• ISO 8092‑1 / ISO 8092‑4 (terminal/tab interfaces)

Keywords: ISO 17447-1, glow plugs, metal‑sheath‑type, diesel engines, cylinder head housing, dimensions, tolerances, threads, installation torque, M10 M12 M14 M9 M8.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 17447-1
Second edition
2022-04
Road Vehicles — Glow plugs with
conical seating and their cylinder
head housing —
Part 1:
Basic characteristics and dimensions
for metal-sheath-type glow plugs
Véhicules routiers — Bougies de préchauffage à fourreau et à siège
conique et leur logement dans la culasse —
Partie 1: Caractéristiques de base et dimensions des bougies de
préchauffage à fourreau de type métallique
Reference number
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions and tolerances .1
4.1 Threads – dimension limits and tolerances. 1
4.2 Glow plugs . 3
4.2.1 General . 3
4.2.2 Heating elements . 4
4.2.3 Electrical connection . 4
4.2.4 Dimensions for M14, M12, M10, M9 and M8 glow plugs . 5
4.3 Cylinder head housing. 7
5 Installation tightening torque .8
Annex A (normative) Pin terminal dimensions .10
Annex B (informative) M8 × 1 glow plugs with 10 mm hexagon and their cylinder head
housing .12
Bibliography .13
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 32,
Electrical and electronic components and general system aspects.
This second edition cancels and replaces the first edition (ISO 17447-1:2015), which has been technically
revised.
The main changes are as follows:
— Tables 1, 2, 4, 6, 7 include now M9x1;
— Figure A.1 includes now M9.
A list of all parts in the ISO 17447 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
The purpose of this document is to provide a compact and concise specification on glow plugs and their
cylinder head housings, which shall replace the existing single standards on each type of glow plugs.
It is intended to specify the main properties, the design requirements and the dimensions of most of the
existing types of glow plugs and their cylinder head housings. This should enable the user to work with
one comprehensive document valid for most types of glow plugs instead of a number of standards each
of them specified for one type only.
This document covers basic characteristics and dimensions for metal-sheath-type glow plugs.
ISO 17447-2 covers basic characteristics and dimensions for ceramic-sheath-type glow plugs. Tests and
requirements are defined in ISO 17447-3.
v
INTERNATIONAL STANDARD ISO 17447-1:2022(E)
Road Vehicles — Glow plugs with conical seating and their
cylinder head housing —
Part 1:
Basic characteristics and dimensions for metal-sheath-
type glow plugs
1 Scope
This document specifies the main properties and dimensions of metal-sheath-type glow plugs, including
the terminals, and the dimensions of their cylinder head housings, for use with diesel (compression
ignition) engines.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 68-1, ISO general purpose screw threads — Basic profile — Part 1: Metric screw threads
ISO 261, ISO general purpose metric screw threads — General plan
ISO 286-1, Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes —
Part 1: Basis of tolerances, deviations and fits
ISO 965-1:2013, ISO general purpose metric screw threads — Tolerances — Part 1: Principles and basic
data
ISO 965-3, ISO general purpose metric screw threads — Tolerances — Part 3: Limit deviations for screw
threads
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Dimensions and tolerances
4.1 Threads – dimension limits and tolerances
The threads of glow plugs and the corresponding tapped holes in cylinder heads shall be in accordance
with ISO 68-1, ISO 261, ISO 965-1 and ISO 965-3.
The tolerance class 6g shall be used for glow-plug threads. For existing designs, tolerance class 6e is
also permitted. New designs shall be to tolerance class 6g.
The thread in the corresponding tapped holes in the cylinder heads shall have tolerance class 6H.
The threads, dimension limits and tolerances of glow plugs and the corresponding tapped holes in the
cylinder head are given in Tables 1 and 2.
Table 1 — Dimension limits
Dimensions in millimetres
Thread size Tolerance Dimension Major diameter Pitch diameter Minor diameter
class
max. min. max. min. max. min.
Plug thread
a
6e (on finished 13,937 13,725 13,125 12,993 12,404 12,181
plug)
M14 × 1,25
Tapped hole
not speci-
6H in the cylin- 14,000 13,368 13,188 12,912 12,647
fied
der head
Plug thread
a
6e (on finished 11,937 11,725 11,125 10,993 10,404 10,181
plug)
M12 × 1,25
Tapped hole
not speci-
6H in the cylin- 12,000 11,368 11,188 10,912 10,647
fied
der head
Plug thread
a
6g (on finished 9,972 9,760 9,160 9,042 8,439 8,251
plug)
M10 × 1,
...