Spark Plug - Gap Modified to Increase Performance
Category 5Applicable Model/s 1986 RX-7
Subject SEMI-SURFACE DISCHARGE (SSD) TYPE SPARK PLUG
Bulletin No. 008/86
Issued 4/29/86
Revised
SSD Type Spark Plug:
Electrode Gap Type Spark Plug:
DESCRIPTION
Increasing the intensity of spark is an important factor for improving fuel economy, performance and emissions. In case of the normal electrode gap type spark plug, the sparking intensity will be increased by widening the electrode gap. However, at the same time the durability of the electrode will be decreased. In order to satisfy both durability and spark, the SSD type spark plugs which have a circular type lateral electrode and a 2 mm electrode gap have been installed in 1986 RX-7. Because of these reasons, use of the electrode gap type spark plug in 1986 RX-7 may cause some of the problems mentioned later in this bulletin. So DO NOT use the electrode gap type in 1986 RX-7. It is also requested that you advise customers about this and recommend the following plugs for use.
Recommended Spark Plug:
NGK SD 10A
Nippon Denso S-29A
Possible problems when Electrode Gap Type is used in 1986 RX-7:
1. Idling stability, driveability and emissions deteriorate.
2. If the spark plug for the old RX-7 EGI (BR9EQ14, W27EDR14) is used in the new RX-7, the temperature of the plug becomes higher, which may result in pre-ignition or breakage of the insulator nose.