hi guys
what sort of sarkplugs do you use
i see KLG Have two types of plug they recommend

Which do you use or do you use some other plug

 

Hi Knares

I use NGK BR7EF



NGK BR7EF Spark Plugs

 

One of the reasons I ask I was talking to a mechanic who told me he will only use bosch spark plugs because they are the only ones he has never had seize in a head

 

I use NGK in my V12s.

Everyone, including mechanics, has their favorites for various reasons....some better than others.

This is the first I've heard of a particular *brand* being more or less likely to seize in the head. Standard practice is to use a tiny smear of anti-seize on the threads to prevent this from happening. If this step is skipped then yes, there might be a difference. And, the threads on some plugs (not sure about Bosch) are plated to (in theory, at least) obviate the need for anti-seize.

Cheers
DD

 

I use NGK BR7EFS for my ‘89 HE V12.
If we are talking V12 please make sure your mechanic uses the correct tightening torque as well as anti seize. The plugs has conical seat and torque shall be 11Nm, a surprisingly low value which most people will exceed if they just tighten without measuring torque.

 

Any tips on procedure how to fit new plugs on a HE, I cant even see some of mine

 

Unbolting the cruise control bellows so it can be moved aside (not hard) and removing throttle pedestal (not hard) helps a lot. For the front two plugs remove the compressor mounting bolts (4) so the compressor can be tilted upward a couple inches at the rear.

Cheers
DD

 

Thanks all; I'm about to replace the plugs in my new 90 V12. Owners manual says use NGK7EFS. It was non-running due to a burned rotor and bad CPS (crank position sensor). I was going to cut the stub on the distributor to prevent burn-through but Orange Blossom advised they burn due to old plugs and HT leads. I am going to replace the bonnet struts and was wondering; is there a maintenance position to tilt the bonnet forward? I.E. since I'll be unbolting the struts anyway, it may give better engine access with the bonnet tilted forward. However; will the grill bind on the bumper, or will the hinges limit forward tilt?

 

I replaced my struts and was thinking of replacing them with longer struts
I found that if I lifted the bonnet up any further in hit the bumper valance, so I had to stay with the original length
The length of my struts are 500mm extended

 

Hi knares

Changing the Spark Plugs on an XJS V12 is almost considered to be a 'rite of passage' and I for one have to admit that even the thought of doing this really freaked me out

As what you find when you have a look beneath that Bonnet/Hood, can be so intimidating that all you really want to do is to close it up again and get back in the Car and go for a drive

But when you think about it, that is really all part of the Fun of having an XJS in as much as eventually you can learn how to do things that might phase some so called professional mechanics

Who may never have ever worked on a V12 either and when it comes to Changing the plugs you could be looking at a Bill from a 'Shop' for $500

So if that doesn't inspire you to have a go yourself then what else will, apart from having the immense satisfaction of doing what appears to be one of the most difficult jobs to do on this Car

But how hard is it really, how hard can it be?

Well I'm not gonna lie, it isn't exactly like having a 'Walk in the Park' especially if you have never done it before

So this was also going to be the very first time for me too and because I was taking my time it took me 3 Days!

As along the way I encountered a number of problems, like Spark Plugs seized in their sockets that didn't want to come out

Namely because the previous owner or the 'Shop' he used, didn't use Anti Seize compound and had also screwed them in far too tight

Which is very easy to do, because it doesn't seem natural to try and do it any other way, except to say those Spark Plugs only need a tweak after they've been put in finger tight with some Anti Seize

But in any event this is a job for which you need to set aside a Weekend, where the secret if there is one, is to take your time and work very slowly and methodically

Labeling every wire you take off and taking lots of Photos, so you don't get lost when you start to put it all back together

Neither of which I did myself and Yes! I did get into a bit of a muddle, which could have been avoided if I had followed my own advice

Where Thankfully 'Greg and Grant' came to the rescue, as when it was all over and She wouldn't Start!

The problem was that I had got the Top and Bottom Coils connected to the wrong bank of Cylinders!

Though once I'd got that sorted out, She Started on the Button and then ran like a 'bird'

One of the problems you're going to find, is that the Bonnet/Hood is right in the way but since my Car 'Cherry Blossom' was under a Car Port

I took off the Bonnet/Hood Struts and tied it 'almost' vertically right up in the Air, while being very careful not to break the Grill 'So you do need to watch what you're doing and as such not lift it too high'

The Hardest Spark Plugs to get to, are under the Air Con Motor, where I found that these looked like as if they had never been changed in the life of the Car

Where its this lack of maintenance, that seems to contribute to those Marelli 'Fires' we keep hearing about and so it is really essential, not to try and cut corners and Change all 12 Plugs

But once its 'done and dusted' you'll then be good to go for around 10,000 Miles before they'll need changing again

And in case I forget to mention it, you can also claim that 'Rite of Passage'

You can see how I Changed my Spark Plugs, on Page: 8 of my 'Cherry Blossom' restoration thread and here is a direct Link to that page: https://www.jaguarforums.com/forum/x...-122634/page8/

 

Your in OZ, we be different.

I use NGK BP6EF in ALL the HE engines. Gapped o 0.025" exactly.

NGK stopped making the Non Resistor version about 12 months ago, so, now I use BPR6EF, and Loctite Anti Seize smeared on the threads.

As for doing the job, Doug has it sorted, BUT, clean each plug area BEFORE removing that plug, and I mean CLEAN. Anything you miss will drop inside that cylinder, and ruin your day.

Remove the distributor cap, #3 on each side, and #4 on B side will have the tool actually in contact with the cap, and you will crack that cap in less than a heartbeat, and then utter odd words of satisfaction.

Alex (aka OB) also has sound advice.

A Sanden compact A/C compressor sorts the #1 plug issue 100%, coz then you can even "see" the plugs.

First time doing them, about 6 hours and 12 stubbies.

I do them now in less than an hour, BUT, my engine V is CLEAN.



Have fun.

 

I have spent a few hours today reading your posts, very informative, thanks for spending the time writing them up.
My car has similar problems, engine won’t run properly, so I was thinking the only thing to do is the plugs, which you have covered
The injectors which you have covered, the injector harness which I saw someone has covered but I can’t remember where I saw that
My rear brakes are stuck on, which you covered and I seem to have an oil leak, I am pretty sure from the gear box
That’s for starters anyway
I didn’t understand when you turned the capstan to get the pulse to the injectors or how you managed to get a photo of the voltage at the injectors as I thought the voltage was there for only a split second
Also to reverse flush the injector, do you need to supply power to the injector
thanks

 

thanks Grant
I certainly won’t be going in to it blind

 

Thanks guys for your guidance
I have changed the plugs and plug leads,
much easier once I read your posts
It now runs like a clock

 

Well done.

Like I say constantly, SIMPLE cars, only made DIFFICULT by over thinking.




by overthinking.