Colder sparkplug for s/c AJ-V8 ? - Page 4 - Jaguar Forums - Jaguar Enthusiasts Forum

Notices
Jaguar Engines & transmissions Discuss performance / modifications / upgrades etc here..

Colder sparkplug for s/c AJ-V8 ?

 
  #61  
Old 03-20-2018, 11:25 AM
8bit's Avatar
Senior Member
Join Date: Oct 2013
Location: Scotland
Posts: 475
Thanked 125 Times in 85 Posts
Default

OK thanks, stock it is then.
 
  #62  
Old 07-08-2018, 03:01 AM
Junior Member
Join Date: Feb 2018
Posts: 20
Thanked 1 Time in 1 Post
Default

Originally Posted by seantoole5 View Post
I worked at Jag as a engine management cal engineer when these engines were being developed (still do infact).

The reason for the "5" heat range plug was to meet sign off for plug foul in extreme cold temperatures. The decision to keep NA and SC engine the same was to prevent NA plugs going into a SC engine by mistake at the factory.

Hot plugs do not cause detonation, they cause pre ignition. Which is very hard to detect, and very destructive. The standard tune on 4.2 SC's (and the NA's for that matter) is tuned to not get the spark plugs to hot. There is an area of the ignition map that is deliberately retarded for this, it is set by using instrumented spark plugs. And in this area the plugs will get hot enough to cause engine failure levels of pre ignition way before any spark induced detonation occurs.
Obviously, anybody trying to tune one of these engines in the after market will not be able to measure this. So fitting colder plugs is absolutely the right way to go. And as others have said, the Aston 4.3 plug is a direct fit.

Cheers
Hello, I've have 15psi boost...I'm experiencing blowouts at high rpms, this Aston 4.3 plug will solve my issue, being that it is a cooler plug?
 

Last edited by Cambo; 07-08-2018 at 04:00 AM.
  #63  
Old 07-08-2018, 03:39 AM
Junior Member
Join Date: Feb 2018
Posts: 20
Thanked 1 Time in 1 Post
Default

Originally Posted by Cambo View Post
And this all got me thinking about the 5.0L engines, what's the story with the plugs on them?

And I found something interesting!

If we look at the X150 XKR with the 5.0L, there were different plugs specified for the regular 5.0L XKR, and the XKR-S.

XKR from B32753 to B45394 = AJ812146 = NGK ILKAR6C-10
XKR from B45395 onward = C2P23089 = ILKR6C-10

XKR-S from B32753 onward = C2P23089 = ILKR6C-10

The C2P23089 is the same plug used in the F-Type V8.

What i see from the various technical manuals is that the 5.0L plug ILKR6C-10 gap is defined as 1mm, no range given. This ILKR6C-10 is shown in the XKR manual, also the F-Type manual. Safe to assume that the gap range is going to be 0.9mm to 1.0mm, and they are probably 0.9mm straight out of the box.

Funny enough the 3.0L AJ126S is spec'd as SILZKAR7C-10S, gap 0.9-1.0 mm

So yeah! The AJ126S runs a colder plug (7) than the AJ133S (6).

It was mentioned in a thread here on the forum about someone putting a tune in an F-Type, and the tuner recommended going to a colder plug. I suppose that's going from a 6 to a 7. Hope they got the gap right!

Here is a 7 plug that looks to be the right one for the 5.0L https://www.ngk.com/product.aspx?zpid=9824
And apparently there is an 8 version which was used on the AMG SLS as an OEM part...
I have a 16' f type r, tuned w/ mods...15psi, do you think thin plug you're recommending will solve my blowout issues
 
  #64  
Old 07-08-2018, 04:05 AM
Cambo's Avatar
Thread Starter
Join Date: Jan 2011
Location: Sydney, Australia
Posts: 8,235
Thanked 3,597 Times in 2,149 Posts
Default

Originally Posted by tu2side View Post
Hello, I've have 15psi boost...I'm experiencing blowouts at high rpms, this Aston 4.3 plug will solve my issue, being that it is a cooler plug?
The sparkplugs used in the Aston 4.3 are totally different to the ones in the 5.0L Jag motor

Originally Posted by tu2side View Post
I have a 16' f type r, tuned w/ mods...15psi, do you think thin plug you're recommending will solve my blowout issues
I'm not recommending anything! This thread was only to investigate and inform of possibilities, there are no recommendations here.

 
 

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread
Advertising
Featured Sponsors
Vendor Directory

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: