Folks,

I've just ordered spark plugs for my other car and realized I've not changed them on the 2003 XJ8.

What are the recommended spark plugs for the 4.2 V8? I looked at the NGK website and was thinking of using BKR5EIX-11 Iridium plugs

Your thoughts?

Tony

 

As you refer to a 4.2 Litre engine I suppose you are on the wrong sub-forum.

 

Apologies, my bad. It is, of course, the 4.0L engine.

Tony

 

That's what I put in mine. Amazon sells em cheap too.

 

I'm looking at replacing the SP's on my 2002. Should it be Jaguar AJ84575 (now C2A1535) or NGK PFR5G-11E? The NGK seem to be hard to find unless you're in the UK.

 

In April this year, I replaced them on our 2001 XJ8. Our Jaguar mechanic (20 plus years experience) recommended NGK Iridum BXR6EIX-11. Although this spark plug is specified for 1998 - 2003 XJR, we have had no performance problems using them in our XJ8.

I bought the NGK Iridum BXR6EIX-11 Spark Plugs (part number 3764) at Advanced Auto Parts. http://shop.advanceautoparts.com/web...R%7CGRPTUNEAMS____

Ordered online with local pickup at store. all 8 spark plugs for a total of $36 (used discount code A123 - 40% discount). Price was $6.99 each, now is $7.09. Discount code A123 (40% off - $20 off of $50) is still ongoing. Total is now $56 less $20 discount.

Jim Lombardi

 

go with the NGK, I got them at advance auto also

 

Hello Jim....according to my info your model should be using
NGK - PFR5G-11E with gap set at 1.1mm
The Iridium equivelant for these is
NGK - BKR5EIX-11

The XJR should be using
NGK - PFR5G-11E with gap set at 1.2mm

The NGK number you have quoted BXR6EIX-11....should be BKR6EIX-11
Which is still wrong even for the 97-99 XJ8
This should be fitted with NGK - BKR5EVXA-13 with gap set at 1.3mm
The Iridium equivelant should be NGK BKR5EIX-11 with plug gap set at 1.2mm

Cheerws,
Maximus

 

Hi
I had to go the NKG UK website and use their Partfinder to get these spark plug part numbers:

2003 XJ8 model year:

A27 03/00 thru 2003 4.0 Recommended - PFR5G-11E stock number 3000
Upgrade - BKR5EIX-11 stock number 5464

2003 XJR
A27 03/00 –> 2003 4.0 Recommended - IFR5N10 stock number 7866
Upgrade - BKR6EIX-11 stock number 3764

Earlier XJ8
A26 09/97 –> 09/98 Recommended - BKR5EVXA-13 stock number 1188
Upgrade BKR5EIX-11 stock number 5464

A26 09/98–>03/00 Recommended - PFR5G-11E stock number 3000
Upgrade BKR5EIX-11 stock number 5464

Earlier XJR
A26 09/97 –> 02/00 Recommended - PFR6G-13E stock number 2341
Upgrade BKR6EIX-11 stock number 3764

A27 03/00 –> 03/02 Recommended - PFR5G-11E stock number 3000
Upgrade BKR6EIX-11 stock number 3764

Note Amazon.com sell NGK PFR5G-11E 5464 but its comment is: This product does not fit your 2003 Jaguar XJ8

Some Ebay sellers also have NGK PFR5G-11E 5464 for around $28 for a package of 4 spark plugs.
Jim Lombardi

 

Hello

I have been trying to find out what is the difference between the BKR5E-11 and BKR6E-11 NGK spark plugs.

I found the following information on the Subaru Forum thread with:

The first post - "I looked for differences between BKR5E-11 and BKR6E-11. I found something but nothing relevant."

"If you do a lot of short trips then a hotter plug might be better."

In one of another post shows a NGK spark table that gives the part number breakdown:

BK = 14mm/ 5/8" (16.0mm) ISO type - Thread Size/Hex Size
R = Resistor Type Construction
5 or 6 = (range 2 Hot -> 12 Cold) Heat Rating Number
E = 19mm (3/4") Thread Reach
11 = 1.1mm (0.44") Wide Gap

I also found the spark plug Part Number breakdown table in this PDF on NGK UK website and saved it is this PDF file:

NGK Spark Plug Part Number Key Table.pdf

I am not sure if the statement about the hotter plug use for a lot of short trips is true.

Jim Lombardi

 

Years ago it was common for owners of older cars to instill a hotter running plug under the theory that with an older engine you are going to have more oil blow by and possibly less precise fuel delivery. The hotter plug would burn off the contaminants.

This has also been suggested to those starting to have running issues with the earlier V8's.

I believe my manual lists the same plug regardless of the SC or not -- the second listed plug was for use in areas without unleaded gasoline. I don't have my manual handy so my memory could be wrong.

The thing I remember not being able to figure out was the final "E" -- I was going to ask my Jaguar parts guy what the dealers are installing.

Considering the minimal cost I normally go with the same OE plug when i change them out - I believe I found them for around $11.00.

 

I was looking on ebay last night and managed to find a seller based in TX that had 4 PFR5G-11E's. Turns out they had another 4 not listed, so they went ahead and listed the second set of 4 and I was able to get all 8 for $57 inc shipping.

 

Hi
Here is the follow up on Spark Plug choice I made for our 2001 XJ8.

The recommended upgrade Spark Plug for the 2001 XJ8 is the NGK BXR5EIX-11 (NGK UK Chart). I noticed that Advance Auto Parts has the NGK BXR6EIX-11 (upgrade for 2001 XJR). I sent this email to NGK USA tech support:

"Can I use NGK BXR6EIX-11 spark plugs in our 2001 XJ8 without any problems? It appears to be for XJR models. I could not find any NGK Iridum plugs listed for XJ8 on the NGK USA website.

Looks like the NGK BXR6EIX-11 is almost the same spark plug as the BXR5EIX-11. Just 1 more higher in heating rating number (means it is just a little colder spark plug).

We changed the original factory spark plug (first time ever since car was put in service) 3 months ago at 100,000 miles. We had our mechanic put in the NGK BXR6EIX-11 and we have not noticed any difference in fuel consumption or performance.

Will the colder heat range plug present any future problems in our XJ8?"

Here is NGK USA Tech Support email reply:
"The 1 step colder heat range won't hinder performance."

I guess this means that the gas mileage, engine performance, and any related engine issues will be same if I use either of these 2 spark plugs.

We paid $36 for the 8 spark plugs online - Advanced Auto Parts with local pickup option and the discount code A123.

Jim Lombardi

 

Since these engines were developed under Ford, shouldn't we be using Autolites?

 

I use Bosch or Champion plugs in all my engines. I would not and will not use NGK products on my vehicles. The Bosch plugs I use in the Jag have 4 electrodes at the bottom which produce a better spark. Bosch Automotive Aftermarket - Spark plugs - Bosch Super 4
In my Triumph I use the specified Champion plugs which work very well, but may try these Bosch ones to see if they make any difference.