Spark Plugs?
 

It's almost time for a new set of spark plugs. Anyone change theirs yet? With what? I suppose I'll go with what the manual says (don't have it with me). Any thoughts that indexing may help MPG? I indexed my plugs on my V12, and it actually was noticable.
Just wondering how easy/hard it was on the HCH I. Wires too?

Thanks for any input.

Re: Spark Plugs?
 

I've heard the plugs are numbered according to how the hole in the head was threaded...to allow the gap to face a certain direction.
If this is true remember you can't put the plug from Cyl 2 into Cyl 4 etc. (Unless those two cylinders had the same number stamped onto them)

Re: Spark Plugs?
 

Which car do you own that has a V12? (waits with curiousity)

VRRRRROOOOOOMMM!!!! hehe, how do you keep tires on it? ok, I am done, Kudos to you though!

Re: Spark Plugs?
 

'94 Jaguar XJ12, 6.0 L V12. Gets considerably less MPG than the HCH ; )
I checked prices on the OEM spark plugs (NKG IFR5G-11K, and Denso SK16PR-L11).
They are VERY pricey! I wasn't expecting to pay ~$13 per plug!!! Wow.

Re: Spark Plugs?
 

I replaced my plugs not long ago. 2003 HCH that I got used. Didn’t do anything special, just replaced them. Got AC Delco equivalent to the recommended plugs from NAPA. They were a little pricy (about $8 each) but not $13! They looked the same (tapered center electrode, etc.) Didn’t loose any performance . . . may even have gained some FE, but I don’t know how old the other plugs were (I assume they were pretty old, car had close to 100,000 at the time) and how much that affected things.

kernk

Re: Spark Plugs?
 

No one mentioned there's EIGHT spark plugs on this engine (dual-plug heads).
Anyone know how to remove the 'snorkel' thingie that covers the front 4 plugs?

Re: Spark Plugs?
 

The "snorkel thingies" (and I believe that is the proper technical term) cover the back four plugs as well . . . the non-technical term for “snorkel thingie” is ignition coil (I think – or something like that, I am guessing). Anyway, just undo the nut on the snorkel thingie, detach the wires that are clipped on to it and pull it off.

You will need a very long extension for your socket wrench (I put two extensions together to make a long enough one), because the plugs are WAY down in there! If you don’t have a rubber gripper in your plug socket you will never get the things out . . .

Re: Spark Plugs?
 

Not the coil 'thingies', but the air intake thingie.

Re: Spark Plugs?
 

Anyone have any pics so that I can see what you are talking about?

Re: Spark Plugs?
 

The plastic cover that says IMA (as I think you know) just pulls off. The forward plastic cover had two bolts (which were under the first plastic cover) and then you just pull real hard and it comes off too. it is held down by two "pins" that fit through rubber rings at the bottom - pulling pretty much straight up works fine. I just removed the hose/tube from the air cleaner where it attached to the front cover (again just pull it out) . . . I didn't remove it from the air cleaner housing. That was all I removed to get to the plugs.

I hope I am being of some help . . .

Re: Spark Plugs?
 

Yep, pretty straight-forward task. I gapped and installed all 8 in probably 10-15 minutes.
I found it easier to remove the coil 'plug' before removing the coil/cap itself.

Re: Spark Plugs?
 

I still can't seem to "find " my plugs. Are they under the black caps with the two screws on top? I thought that was the fuel injection. I can take off the two "covers" that you mention but still can't locate the plugs. I feel like a real Da, as I have changed the plugs on my cars for the past 30 years myself. Can anyone post a pic on this?
Thanks for your help.

Re: Spark Plugs?
 

Under the plastic covers there are eight rectangular things with shiny black tops (at least mine are shiny), four in the front of the engine and four in the back. Each is held on with one bolt and connected to some wires with a plastic connecter that has a thumb clip.

Hay, I found a diagram and downloaded it in the Share ares (here: https://www.greenhybrid.com/share/image1885.html ) . . . the things labeled 1 & 2 are the coils, remove them and you will find the plugs, way down in there.

Re: Spark Plugs?
 

Thanks Kernk, that clears it up. I was on the right track. I just wasn't sure if those were the plugs or thefuel injection.

Re: Spark Plugs?
 

I swapped out the iridium Densos at 108k miles (looked like they had another 20+k miles to go on them really), with Platinum tipped Densos to save money ($2.99 each). Don't bother replacing these plugs unless you notice a misfire.
You will need a 5/8ths in spark plug socket, with a rubber gripper inside, and a 10mm socket, for everything else.