looking for colder spark plugs on the 3.0Liter
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From: Metrowest Boston
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.
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.
In looking through my service records, it’s been 6 years/45K miles since I changed plugs, well past what’s recommended for the V6S.
I’ve been getting a bit of pinging at lower revs and medium load, though i might not hear it at higher revs with engine/exhaust noise. I see that in 2019, the dealer installed C2Z28434, which is for the later VINs, and is SILZKAR7E8S and what the NGK site recommends. My S/N is 2622, which according to Cambo’s notes would be a SILZKAR7C10S.
Any clue which one I should suggest to my Indy mechanic? The pinging is fairly recent. Thanks.
Edit: looks like the SILZKAR7C10S is obsolete, so I guess I use the SILZKAR7E8S. With standard gap?
Last edited by DJS; Jun 6, 2025 at 12:23 PM.
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