Dears:

I'm sure this topic has been exploited, but my question is specific. For 99/00 XJRs, NGK suggests using PFR6G-13E. Is it advisable to (upgrade) to the Iridium BKR6EIX-11P, or would you advise against it? I am very much hoping to gain actual experience here..
And say if you do use the latter, do you have to manually change the gap?

Other suggestions welcomed, but I usually stay away from the recent Bosch.

Appreciate it!

 

I've used Bosch for years in all my cars and never had a problem with them. I've just fitted a brand new set of Bosch Super 4's in my XJ and she's running better than ever.

 

I run the NGK Iridiums in my R. Runs great.

RE: The gap.

They are "supposed" to be properly set at the factory but should be carefully checked before installation.

The reason for the factory setting and the need to be cautious when checking them is that the tiny center electrode can be easily damaged/broken if you go gorilla on them when checking or re-setting the gap.

Mine were perfectly gapped out of the box.

Also, they are said to have a factory anti-seize coating on the threads, so they say there is no need to use any when installing them. I used a tiny bit of anti-seize anyway because of the nightmare of a stuck plug so deep in the aluminum head. Torque to specs.
Vector

 

+1

I've found all R's I've used are happy with the NGK IFR5N10 - the '10' at the end is 1mm gap. These engines run hotter than NA units.

 

I'm pretty sure that they have been superseded to iridium now, for all the S/C engines back to 308. You shouldn't have to gap them, should be pre-gapped.

 

For the Aj26 S/C the gap is ~.050, check here if your vin fits in the TSB range. The Aj27 engines which were in 00+ the gap was shortened, to about .040 range. See post 17 here https://www.jaguarforums.com/forum/x...00-rpm-174847/

Apparently my engine is a AJ26.5s since it's a 99 MY but I'm above the AJ26 vin cutoff, just realizing that now

 

Running those too. Runs great.

 

Hi Guys!

Some very interesting and very helpful insights you offered. Thank you! I have decided to try out BKR6EIX-11P, to replace my current IFR5N10 in my 99/00 R. Will give you a report!

 

Sorry bad post