How do these spark plugs look?

[JHZR2]

Hi,

My 91 BMW 318i used dual-electrode NGK plugs as OE. I replace them every 30k or so, as PM... I kind of think that I don't need to...

Here are all four:

From the back of the engine (nearest the firewall, not sure of cylinder number):

This bottom one is the frontmost cyllinder.

Two look dry, two look wet. The threads on three of them look wet. I know for certain, since I took them out, that all four came out of the engine dry and clean. There was a bit of oil in the spark plug holes (time for a new valve cover and spark plug gaskets, I guess) that coated the electrode betwen when I took them out and when I took pictures.

Overall they look good to me. They were all consistently colored, and there were only minimal deposits on the outside of the electrodes, none on the center electrode.

All came out very easy, no issues.

Any thoughts? I suppose I could have gone much farther, right???

THanks!

JMH

 

[buster]

I think you could have gone further but I personally would just replace them. You might pick up a mpg or two. But you are right they don't look bad. Nice pics!

 

[JHZR2]

thanks for the compliment... maybe Mori will chime in on this thread and state how I could do them better, but I was just quick shooting with my 105mm nikkor 2.8 macro lens and the camera in macro mode. I wush I could really highlight how they look... there is a learning curve for sure!

JMH

 

[mechtech2]

I had a 320i, but are your plugs getting any oil from an outside source? Like a leaking valve cover gasket?
They are a bit too wet for me. The threads on all of them, and the insulator on one of them.
Maybe a slight ring or valve guide problem.
German cars used to spec a heavier oil than most, and after 2,000 miles on fresh oil, mine would start burning it a bit.
Do you notice no oil use, then after a while it starts to use a bit?

 

[moribundman]

Originally Posted By: JHZR2
thanks for the compliment... maybe Mori will chime in on this thread and state how I could do them better


Next time, take the pictures with a less direct light source. The images are little dark and quite a bit too contrasty. Adjust "Curves" in Photoshop for more shadow detail and for adjusting tonal range in general.

 

[JHZR2]

Originally Posted By: mechtech2
I had a 320i, but are your plugs getting any oil from an outside source? Like a leaking valve cover gasket?
They are a bit too wet for me. The threads on all of them, and the insulator on one of them.
Maybe a slight ring or valve guide problem.
German cars used to spec a heavier oil than most, and after 2,000 miles on fresh oil, mine would start burning it a bit.
Do you notice no oil use, then after a while it starts to use a bit?


No, there is oil leakage into the holes in which the plugs sit. They are sealed from the top by a valve cover gasket that is leaky.

The plugs came out perfectly dry, but the socket and top of the plug were covered in oil. As I pulled it out and gravity did its thing, oil slopped down the threads and onto the electrode.

They definitely a ll came out bone dry.

JMH