So I have done a bunch of research on spark plugs for the HE v12 and 6.0 V12 and have some questions for my 94 6.0 v12.

My original XJS motor is the 5.3 which is rated for a NGK BR7EF (V style), NGK BR7EFS (standard plug) both gapped for .025" gap as per Kirby's Recommendations.

My 94 xj12 6.0 is rated for two spark plugs both V style at .025" gap just different temperature rating. BR7EF (colder) for first half of 94 and BR6EF (hotter) from late 94 to end of production.

I am currently leaning toward putting in the later (hotter) BR6EF NGK spark plug in my 6.0 as that is what Jag did and that is what it had before. Does anyone have any suggestions or recommendations for a colder vs hotter plug?

Thanks!

 

Below are some great reading on the spark plug debate: Believe it or not I am not the first to have problems deciding on which spark plug. I am going to go with the BR7EF plug as I already have them, if i have any issues I can always switch.


JagFORUM Logon
JagFORUM Logon
JagFORUM Logon
JagFORUM Logon
JagFORUM Logon

 

I have used the "6" heat range in all mine for as long as I can remember.

I dont use the "R" spec either. That might change as the non R's are getting hard to find now.