The OEM plug for the 3.0L is the NGK 93476 SILZKAR7E8S Laser Iridium Plug.

Can anyone help me find a one step colder plug that has a non-protruded tip. I have called around and can;t seem to find anything. I am hoping someone here in the F Type side can help out since there are lots of people tuning the 3.0 and 5.0 engines on this side. I am about to begin install of another power-adder in addition to the tune/lower crank pulley so that will need to run a one step colder plug, but MUST NOT have the protruded tip.

The kit is almost here and after initial flow testing, I will begin climbing the ladder, but can't go far without addressing the protruded tip on the iridium plugs. I know I will likely not find an iridium plug and that is not a problem.

I can go with a shorter plug life since I will be checking them often anyways.

The NGK SILKAR8AI-9 is the next colder step in the Iridium range, but the tips are longer than the leggy blonde's nipples on a cold day.

 

The stock plug is already heat range 8, which is a pretty "cold" plug already.
The stock V8 plugs are heat range 7.
I have a feeling that the stock plug will be OK unless you are going for a mad increase in boost and power.
I have already bought a set of new SILZKAR7E8S plugs ready for the three year service in 2.5 months' time, the plugs on the V6S are due to be changed after 3 years but the plugs on all other F-Types aren't due for 4 years, which tells me that the S is a little harder on the plugs so maybe you could benefit by going to heat range 9.
Shortly after I get the service done and the plugs renewed I will be adding the lower pulley and tune and I will probably get it dyno'ed, which may or may not show up any problems with having too "hot" a plug.

 

Where did you see that? The 2014 maintenance guide says 6 years/96,000 miles for all F-types.

And I believe VelocityAP sells colder plugs, but I'm not positive.

 

I got it slightly mixed up, the copy I have of the 2014 MY service schedule says every 3 years for the S and every 6 years (not 4) for the others, copy attached.

 

Regardless.... stepping down in heat is secondary to finding a plug that does not protrude as much as the iridium plugs do. That is where I am concerned. That tip will become a glow point!!!

 

As of April, Chris at VAP had not yet found a colder plug for the V6. They do offer the colder plug for the V8.

 

The AJ126S has a 7, the AJ133S has a 6, as stock plugs.

There are/were two different plugs for the AJ126S, have a look here https://www.jaguarforums.com/forum/j...2/#post1662011

AJ812988, up to K05405 in the F-Type, up to U04717 in the X250 XF
C2Z28434 from K05406 in the F-Type, from U04718 in the X250 XF

AJ812988 is the SILZKAR7C10S

C2Z28434 is SILZKAR7E8S according to what's under the label of the OEM box.



So it would appear that the C2Z28434 is actually a 0.8mm gapped plug?

And JLR changed the spec of the plug not too long after introducing the engine... there must be a reason why...

But there are some part numbers to cross check for a heat range 8 plug...
EDIT, here this looks about right https://www.ngk.com/product.aspx?zpid=9718

Those 8's are OEM fitment for the Nissan GTR, and you can bet a tuned GTR motor get's more of a hammering than the Jag motors.

 

The difference between the earlier and later plugs appears to be gapping only (0.8 vs 1.0mm) and both in the 7 heat range.


Here is a colder plug that may work, but I don't know enough to know definitively:
ILKAR8C10. Would have to measure out the two and confirm the seat/gasket is identical.

 

First I've seen that. My 'Passport to Service', is the same as this, which someone else posted. Guess I'd go with the more conservative one, which is what you posted.
https://www.dropbox.com/s/nxh35s5yx3...edule.pdf?dl=0

 

Cambo...the Iridium plugs are not going to work for my application. The tips are protruded. I need NON-protruded plugs that have the same thread pitch, reach, and seat and these. Is there anywhere I can go to cross reference this plug? I like that it is a colder range, but I won;t feel comfortable putting the iridium plugs in with the power-adder application I am installing because of the the higher potential for pre-ignition due to the protruded tips.

 

You planning on running higher compression (hemi pistons, shaved heads, etc.)?

 

I thought I read that he may be doing a fairly heavy Nitrous shot.

 

I honestly don;t know how to answer that. I have looked high and low for internal mods like cams, valves, etc. with no luck. I also want to keep a long flat torque curve thoughout the RPM range...I want it to be FAT AND TALL!!! so I don;t want to begin making mods that will give me an unusable skinny band of power. My choice of power-adder is based on the likelihood of achieving relatively good results without tearing into the block. But I want to make sure the mod is as safe as can be. Right now, it looks like I will have to roll the dice with the iridium plugs that Cambo recommended (NGK 93026 DILKAR8A8) because it's not looking like there are 12 mm thread non-projected plugs. Everything I am finding is a 14 mm thread.

 

correct. Planning to climb up to a 150hp shot. Along the way, I will be installing the upgraded intercooler from EuroToys and I am currently in touch with a guy in the UK about having a Quaife Diff. modded to fit the XF.

 

I certainly would love to swap out the OEM LSD for a Quaife. The OEM Diff appears to be a weak link, and the geared mechanism of the Quaife is far more durable than the clutch stacked ZF LSD.

 

If it can be done, it's definitely something to put on the Xmas list !!

 

Hey guys, my v6s is about to reach 3 years so I wanna change the spark plugs.

Based on what I read, I should get one step colder (8) and gap it at 1.0mm?

I have the VAP tune and pulley, intake, decat


Thanks

 

Check with VAP. They may even have the right plugs for you.

 

Thanks, I did write Stuart an email before asking. Let you guys know what he suggests

 

here is what Chris at VAP told me:

The parts number from NGK is 6706 and plug code is LKAR8AI-9. These plugs come gapped at 0.035”, if same charged pressure is used then gap at 0.032”, if charged pressure is increased they will need to be gapped at 0.028”. The gapping is important to prevent a misfire. Now, the bad news..being this plug is not the same metal type to meet iridium mileage advertised guidelines, it will need to be replaced ever 2 years and/or 20-30k mls. (Ignore advised mentions of 5yrs/60k mls). If you’re ok with that, then all is good and just make sure to gap the plugs as needed.