I am running the cheap Champion Copper Plugs. They have about 1k on them.

What is everyone else using? I ask because I failed smog with what seems to be a secondary ignition issue.

 

ALL my Jags have ALWAYS run NGK standard spec, and non resistor type, up until the X300 which is resistor spec only.

NO fancy wa wa wa, in any of them.

The S Types both run NGK Iridium, as specified.

 

Many years ago I tried Champions but they always seemed to foul very quickly.

I then tried Autolite's or NGK's. Never had fouling problems with any of them. I usually use Autolite's on my domestic cars and NGK's on the foreign ones. Been working great for me for many years.

Mark

 

I use Bosch super plus.
I once hear from a crazy Jag fellow who has owned nearly 100 XJSs that Champion makes the engine smoother than NGK, he seems to think it is because the Champion's electrode stick out more than NGK's (I have no idea if this is right though, it seems reasonable)
But Champion's quality isn't good these days... The Bosch plugs have similar shape and stable quality, so he recommends them to me and I have been using them.

I have used NGK(resistor), Autolite, Champion and Bosch and actually I like Bosch the best.
As Grant says, non resistor NGK might be better than the resistor one.

From the view of quality, either NGK and Bosch would be the best choice I think.

 

For the NGKs, is that the BKR6E or the BKR5E?

Most sites recommend the 6E, but that seems to match the heat range of the original RC9YCC specified spark plug. The 5E matches the heat range of the updated specified RC12YCC.

 

Based on my experience with 2 smoke, um, 2 stroke motorcycles, the Iridium plugs eliminated fouling and extended life at least 4 or 5 times. But its also not recommended to try and gap the Iridium plugs due to the fine electrode. So, that may be a problem with the V12 gap. Has anybody successfully used an Iridium plug with the HE V12?

l need some plug wires as well , what is special about this NGK set that its $115 compared Vo the Bosch set for $40 ?NGK/Wireset 54303 at AutoZone.com

 

I've been running NGK iridium in my V-12 XJS fir 6 years as well as my TR-6 and X-300. The gap adjust just like any other plug. Ran them in my Midget and Lincoln LS as well. Never a problem or a foul.

 

I have found some good buys and bad buys from AutoZone, just look around for a decent price, I am about to change my spark plug wires an bought a set of the Bosches, but I think I got mine off EBay,(Love that sight LOL). Like said, Auto Zone can have some outrageous pricing on some of the Jag items, look what they want for the ICM, last I saw over 900.00!!! crazy, got one at way less on EBAY.

 

I use the NGK BP6EF on the 5.3 HE. Always have, and no issues.

Gapped to 0.025" is mandatory.

Dont have a 6ltr so no idea.

PreHE is different again, and I use BP5EY in mine.

 

NGK iridium in my V-12 XJS ? BPR5EIX 6597

 

The AJ16 is a strange bird. Because of the TSB, I have noticed that the auto selections made on wesbites such as RockAuto and Advanced Auto does identify the Champion RC12YC spark plug as the correct fit, but it seems to select the wrong NGK spark plugs.

The NGK spark plugs are always selected with the "6" in the model number, whereas it appears that it should carry a "5", according to spark plug interchange websites.

The "6" model seems to be the proper replacement for the orginally specified Champion RC9YCC spark plugs.

I wonder if this is why everyone says to stick with Champion plugs. The others are mis-specified!

 

this looks like spam to me

 

It did to me too. sparkguru is no longer with us.

Graham

 

I use in my AJ16 engines of the XJS and X300 NGK iridium 'BKR6EIX'

 

In my 89 and 90 XJS V12's I am running NGK BR7EF and stayed well away from the Iridium type on advice from 'The Wizard' and as a result She runs perfect!

 

 

The engines running better after this change. But I always fill the tank with high octane gasoline, 98 RON. On the X300 is a revised crank sensor bracket which 5degrees the ignition early. But both engines running fine. Also on the XJS I'm going to place this bracket.