Installation Guide: DENSO Iridium

DENSO Global | SITE MAP | DOWNLOADS | HELP

Home
IR Technology
Find My Part
Where To Buy
Installation & Gapping
FAQ
About
Site Map
Contact
Headlines
Downloads
Legal
Privacy
Help

IRIDIUM POWER™ GAPPING TIPS

Before attempting to gap any DENSO Iridium Power spark plug, please review the specification chart in the front of this catalog to verify the factory-preset gap. In most cases your Iridium Power plugs do not need to be gapped. Even with small variations in the factory set gap the ultra-efficient firing power design will compensate for those small variations.

Should you decide to re-gap your Iridium Power plug, use extreme caution as improper gapping may damage or destroy the Iridium center electrode or porcelain center.

To increase the gap size:

Step 1: Use needle nose pliers or spark plug gapping tool to bend the ground strap up to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN.

Step 2: Re-check the gap with a calibrated gapping tool.

To decrease the gap size:

Step 1:Use the same method as above, however bend the ground strap down to the desired height. DO NOT LET THE PLIERS OR GAPPING TOOL TOUCH THE IRIDIUM CENTER ELECTRODE OR PORCELAIN.

Step 2: Re-check the gap with a calibrated gapping tool. WARNING: Failure to follow these directions may permanently damage the spark plug. Note: Never use a round gapping tool to check the gap or to increase or decrease the gap setting.

WARNING: Failure to follow these directions may permanently damage the spark plug. Note: Never use a round gapping tool to check the gap or to increase or decrease the gap setting.

Installation Key Points

The threaded area of the cylinder head must be clean.
Using your fingers, screw the spark plug into the cylinder head, and tighten about 1/4-1/2 turn with a plug wrench. (Taper seat plug: about 1/16 turn)
Tightening too much may cause distortion of the plug housing, and in extreme cases could cause engine damage. Therefore, proper installation of the spark plug is important for life and performance of the spark plug.

Plug Size	Cast Iron Heads		Aluminum Heads
Plug Size	N*m	lb-ft	N*m	lb-ft
10mm Flat Seat	10-15	7-11	10-15	7-11
12mm Flat Seat	15-25	11-18	15-25	11-18
14mm Flat Seat	35-40	26-30	20-30	15-22
14mm Taper Seat	9-20	7-15	9-20	7-15
18mm Flat Seat	43-52	32-38	38-46	28-34
18mm Taper Seat	20-27	15-20	20-27	15-20

Note: The installation torque values shown above apply to new spark plugs without lubricating the threads. If threads are lubricated, the torque value should be reduced by approximately 1/2 to avoid over-tightening.
* 1N*m = 0.1020 kgf*m

Installation Procedure

Whenever possible it is recommended that the spark plug should be installed by using a torque wrench. If a torque wrench is not available, tighten in the following manner.

FLAT SEAT PLUGS

TAPER SEAT PLUGS