TIMESERT® HOW TO MEASURE SPARK PLUG SIZE AND REACH FOR THREAD REPAIR KITS
To measure correctly for the length of insert you need for your application. Measure from under the spark plug (Washer) or (middle of taper for tapered seat) to the last thread. (Not to the end of the electrode). This will give you the correct length. TIME-SERT inserts cannot be shortened. Below is an example how Time-Sert would measure for length.
If you would like to try to look up your spark plug SIZE and length yourself use www.Sparkplugs.com when you find the size Click on “Specs” Size and Reach. Sparkplugs.com measures reach different from Time-Sert. Sparkplugs.com measures Thread Reach from above the washer to the END of the spark plug. TIME-SERT measures Thread Reach from under the washer to the LAST thread. EXAMPLE IF YOU GET YOUR SPARK PLUG LENGTH FROM SPARKPLUGS.COM and your plug reach is 19mm subtract 2.5mm for the washer which is 16.5mm The insert closest to this length is 16.8mm in the M14x1.25 which is p/n 44111 M14x1.25×16.8mm is commonly used on many Toyota, Honda, Acura, BMW and Mercedes vehicles. Please check your spark plug size to verify correct length.
Measuring reach for insert length in TIME-SERT® stripped spark plug thread repair kits and inserts.