120 replies to this topic

[BayouTiger]

Jay.... Have a bud plug both tails with some old rags when the engine is idling. Listen to the manifolds....if there is a leak...you will hear it while the tailpipes are plugged.

 

Stevo

 

[Speedy]

Well, I FINALLY got time to pull the plugs tonight.  Something seems funky with CYL 6, which is also where I hear the sound with the mechanic's stethoscope.  All the plugs looked perfect except for these from CYL 6 which were green?? 

 

I'll pull the valve cover when I get time.  My suspicion is that the lifter has crapped out and the intake valve isn't opening or isn't opening all the way and this cylinder isn't getting proper fueling, thus the green color.

 

 

 

[srt5939]

Go out and pull the head now, were waiting for pics 

[Speedy]

I'm getting old and tired

[BayouTiger]

Lifter sounds like a possibility. I wonder if you swapped them with another cylinder and checked them after awhile. Of course you might not want to be beating on it at this point. 

 

From this article:

 

http://grounds-mag.c...ng_spark_plugs/

 

One sign of heat used by some professionals is electrode color. Many--but not all--spark-plug electrodes have an alloy composition that will oxidize green when subjected to high temperatures (see Photo 2, again). This nickel oxide on the center wire and sidewire would show up first at the tip of the electrode--the hottest part--and progress from there, depending on temperature. Excessive green oxide may signal it's time to change to a colder plug. Several causes of high spark-plug temperature are described in the boxed information at left. The main thing to keep in mind here is that not all electrodes oxidize (turn green) at the same rate, if at all. Therefore, your best bet is to turn to a technician with experience reading plugs.

[lakersfan7272]

What plugs do you run Jay?

[TA340]

Boy I sure hope that it is a low cost repair. Those plugs look strange. Never saw that color on a plug before.

[Speedy]

Those are one step colder NGK Iridiums that have been in the car since CF3 and weren't ever green.

Good info Chuck...either heat or oxidization is my theory.

[lakersfan7272]

You haven't changed your plugs in over a year?!

[Speedy]

You haven't changed your plugs in over a year?!

Haven't had a need. Less than 5K on these.

[dodgetime]

a component of iridium (trichloride) emits green, could be part of it on that anode

[345_CHLNGR]

104+ Octane Booster can cause spark plugs to turn green.

[Speedy]

I hear ya but only on one cylinder where there is mechanical noise is a concern.

[srt5939]

Sell them plugs to Frank, they match his car.
Jay do a compression check on 6 that should show leak down if the seats bad.

[TA340]

I have also read that oxidation can turn the electrode green which can also be a result of high temperatures or a lean condition. So you may be on the right track if in fact the intake valve is not opening all the way. Hopefully it is as simple as a collapsed lifter.

[chukarboy]

Speedy,

 

Just for fun take the temp (IR gun) at that exhaust port outlet or around it and compare to the others. It would be interesting to see if there's much of a difference.

 

I trouble shoot industrial machines all the time using this method and will generally catch what bank has a bad valve. These are on

VW 16 cly machines and minimize the tear down.

[toofart]

Just for fun take the temp (IR gun) at that exhaust port outlet or around it and compare to the others. It would be interesting to see if there's much of a difference.

 

 

Damn... sometimes we all get wrapped into the datalogging computer stuff we forget about the old school.  Good tip.

[1FST4DR]

Excellent tip!   Easy to spot a dead cylinder especially if running headers.. The factory manifolds "May" not work so well.  But worth a shot..

[Speedy]

That's a good idea.

[sharkcohen]

Damn good idea.