Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: omega2018 on 07 June 2017, 22:53:41

Title: yellow spark plug
Post by: omega2018 on 07 June 2017, 22:53:41
follows on from my 'v6 just dies' http://www.omegaowners.com/forum/index.php?topic=139765.0 (http://www.omegaowners.com/forum/index.php?topic=139765.0) topic this is a bit odd so posting here as a new topic.  plug number 4 is yellow unlike all the others:
(https://image.ibb.co/nF9o5v/spark_plugs_june_2017s.jpg)
any ideas why?

mileage on these plugs 29K
Title: Re: yellow spark plug
Post by: Kevin Wood on 07 June 2017, 23:01:58
Was it loose in the head when you removed it?

Just wondering if that's carbon I can see on the threads, and maybe a little oil that's been working its' way past the washer. That might have caused it to run a bit cool due to poor combustion in that pot, and hence it's got a little glazed?
Title: Re: yellow spark plug
Post by: omega2018 on 07 June 2017, 23:19:37
yes i was wondering if it was loose.  that would be my preferred explanation.  didn't notice it when removing it and i am always careful to torque them up when fitting. however i do recall having issues with the rubber bung in the socket attaching to the plugs and having to remove one or two plugs after fitting to get it off again (thus crushing the crush washer twice).  i have since glued the rubber to the inside of the socket.

threads look very similar to number 3, no carbon just oil from unscrewing though a small amount of it. 
Title: Re: yellow spark plug
Post by: Kevin Wood on 07 June 2017, 23:51:31
They do tend to work loose in time.

When fitting, I always torque them up, then go and have a brew before returning and checking them again. Often they need a little more as the washer has compressed a little.

Even still, I had a misfire yesterday that I believe was down to a plug having worked loose.
Title: Re: yellow spark plug
Post by: omega2018 on 08 June 2017, 00:00:36
i admit to copper greasing these plugs when fitted.   

i should add for what it's worth there have been no relevant error codes for the life of these plugs except, recently, misfire cylinder 5 (not 4) during the 'V6 just dies ' problem. crank sensor failed 17K miles into their lives but threw no codes. 
Title: Re: yellow spark plug
Post by: Doctor Gollum on 08 June 2017, 02:02:18
iadmit to copper greasing these plugs when fitted.

i should add for what it's worth there have been no relevant error codes for the life of these plugs except, recently, misfire cylinder 5 (not 4) during the 'V6 just dies ' problem. crank sensor failed 17K miles into their lives but threw no codes.
That will really help the cats. Not :o
Title: Re: yellow spark plug
Post by: omega2018 on 08 June 2017, 12:31:02
iadmit to copper greasing these plugs when fitted.

i should add for what it's worth there have been no relevant error codes for the life of these plugs except, recently, misfire cylinder 5 (not 4) during the 'V6 just dies ' problem. crank sensor failed 17K miles into their lives but threw no codes.
That will really help the cats. Not :o
not even the dollop i put on each electrode? ::) 

of course i didn't put the grease anywhere near where it could get into the cylinder so there is no chance of it getting to the cats,  what a pointless post ???.

 i mentioned the grease because it 'might' have assisted the plug in working loose (though i very much doubt it, it would have helped the plug get more screwed in for the same given torque). for steel plugs sitting in a alu head for up to 80K miles it is fairly common to copper grease the threads.  not to mention to help avoid cross threading them.  this time when i put the plugs in i did it dry because they went in easily by hand on the end of a rubber tube.
Title: Re: yellow spark plug
Post by: Doctor Gollum on 08 June 2017, 13:35:18
Have personally experienced plugs working loose in less than 20k. Without grease.

If you honestly believe that no copper slip made its way to the cylinder then you're mistaken. And before you say minute, rember that the cats work on a molecular level...
Title: Re: yellow spark plug
Post by: omega2018 on 08 June 2017, 14:15:29
Have personally experienced plugs working loose in less than 20k. Without grease.

If you honestly believe that no copper slip made its way to the cylinder then you're mistaken. And before you say minute, rember that the cats work on a molecular level...

this is just stupid.  copper is already in cats.  copper is used in fuel lines. copper is already in petrol. i've never seen anywhere that copper grease should not be used for spark plugs because of the cats.  then there is the issue of how does it physically get into the cylinder, assuming it is applied to the plug thread and not the cylinder thread (which it was).   "minute" amounts? given any miniscule amount will go on the first piston fire in 80,000 miles of motoring i don't think the word 'minute cover it'.  "cats work on a molecular level.." ok sherlock so in an urban area at street level how many molecules of copper are already in the air that gets sucked into the cylinders, over 80,000 miles of motoring? bit more than a few molecules left on a spark plug thread i think. ;D
Title: Re: yellow spark plug
Post by: TheBoy on 08 June 2017, 17:21:29
Plugs do tend to work loose around 30k, hence I've never seen the point in the quad electrode plugs, and always fit twins to mine...   ...and secretly hope it helps with the difficult to ignite LPG burn.
Title: Re: yellow spark plug
Post by: Kevin Wood on 08 June 2017, 17:35:41
Just to be different.. mine are currently triple electrodes. :D
Title: Re: yellow spark plug
Post by: Nick W on 08 June 2017, 18:04:36
iadmit to copper greasing these plugs when fitted.

That will really help the cats. Not :o


If you've ever had to deal with a seized/broken plug, or a stripped thread you would ALWAYS use a smear of copperslip on plugs. Those were bad enough on OHV engines, where the plugs tended to be accessible. But a modern 4 valve per cylinder where they're buried deep in the head makes for a difficult and/or costly repair.


As for the OP's original problem, it still sounds like a faulty MAF to me.
Title: Re: yellow spark plug
Post by: omega2018 on 08 June 2017, 19:32:04
i admit to copper greasing these plugs when fitted.

i should add for what it's worth there have been no relevant error codes for the life of these plugs except, recently, misfire cylinder 5 (not 4) during the 'V6 just dies ' problem. crank sensor failed 17K miles into their lives but threw no codes.
That will really help the cats. Not :o

oh dear, lots of dead cats then...

"Almost all spark plugs use a copper cored Center Electrode to conduct the electricity, jump the gap, and promote heat dissipation. " www.ngk.com
(https://carsales.li.csnstatic.com/partsales/parts/general/pg5750072766802110774.jpg)
(http://www.corvette-web-central.com/images/spark_plug.jpg)


etc.. etc...
Title: Re: yellow spark plug
Post by: Doctor Gollum on 08 June 2017, 21:01:43
I would probably spend more effort trying to solve the problem instead of picking holes...

Then again, it's not my car... So crack on ;D
Title: Re: yellow spark plug
Post by: Webby the Bear on 08 June 2017, 21:54:43
I don't lubricate plugs but I would put a drop of oil on the threads if I thought there was going to be an issue getting them out.
Title: Re: yellow spark plug
Post by: Nick W on 09 June 2017, 00:26:05
I don't lubricate plugs but I would put a drop of oil on the threads if I thought there was going to be an issue getting them out.


whoever fitted the plugs on this week's Yak 18t didn't use copperslip. 3 of them loosened properly; the other 15 needed a long ratchet, fluent anglo-saxon and some prayer. I never fit plugs without lubricant.
Title: Re: yellow spark plug
Post by: Marks DTM Calib on 09 June 2017, 15:09:13
I don't lubricate plugs but I would put a drop of oil on the threads if I thought there was going to be an issue getting them out.


whoever fitted the plugs on this week's Yak 18t didn't use copperslip. 3 of them loosened properly; the other 15 needed a long ratchet, fluent anglo-saxon and some prayer. I never fit plugs without lubricant.

On the old tapered seat plugs I would agree (ala the horrific abortion that was the Ford pushrod where the plugs were mounted at the front in the wet and spray with a tapered plug seat) then yes I would agree.

The modern plug its not an issue IF its fitted correctly  :y
Title: Re: yellow spark plug
Post by: Kevin Wood on 09 June 2017, 15:25:25
whoever fitted the plugs on this week's Yak 18t didn't use copperslip. 3 of them loosened properly; the other 15 needed a long ratchet, fluent anglo-saxon and some prayer. I never fit plugs without lubricant.

Correct response is, of course, to "take it for an Italian tune-up" to see if the heat loosens them. (http://www.the-wood-family.com/Smilies/crazy_pilot.gif)

 ;)
Title: Re: yellow spark plug
Post by: omega2018 on 09 June 2017, 17:46:01
I don't lubricate plugs but I would put a drop of oil on the threads if I thought there was going to be an issue getting them out.
forgot to mention,  engine oil contains copper molecules....
Title: Re: yellow spark plug
Post by: Doctor Gollum on 09 June 2017, 18:18:11
You've made your point >:(