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Spark Plugs Erosion

Vlad

Well Known Member
Just an observation. Plugs are checked visually, cleaned and rotated every oil change. Carburetor, conventional magnetos.


Electrodes at 40 hours.


40.jpg



The same plug at 400 hours.


400.jpg
 
That looks about normal to me for 400 - 600 hours - I was always taught that when the ellipse is 2:1, the sparkplug has done its duty and should be retired....and I figure 500 hours as a nominal life.
 
Every EI manufacturer should use these in their marketing material :) as a reminder what you won't see if you use Iridium auto plugs...

On a more serious note .. all looks normal there.. even if not exactly desired :)
 
v, have you been regapping them?
img0756h.jpg


my iridiums have over 1,000 hrs and plan on going beyond TBO. expensive to purchase but pay for themselves in YOU fly a lot. were you going next?
img0757x.jpg


lookn forward to seeing your plane in paint some day. :D
 
calling all experts....

....so where did I read that you should Move the plugs (rotate to another cylinder) so that they are fired by the 'other' mag for 1/2 their life, thus the anode wears, then the cathode? coulda swore it was in the official documentation for Champion plugs or something.
If true, it wouldn't double the life, but just even out the wear a bit?
 
Try gapping and rotating every 50 hours. 16-18 though.

Check resistance at the same time and replace any over 5000 ohms. Or buy Tempest.

Irridium is great, just do not drop them even once! :eek:
 
....so where did I read that you should Move the plugs (rotate to another cylinder) so that they are fired by the 'other' mag for 1/2 their life, thus the anode wears, then the cathode? coulda swore it was in the official documentation for Champion plugs or something.
If true, it wouldn't double the life, but just even out the wear a bit?

Page 7 of the Champion link above... and here....

http://www.championaerospace.com/assets/AV6-R-Nov2004.pdf
 
Interesting note from that document on the page Gil cited:

"Four cylinder engines equipped with single drive dual magneto fire with constant polarity, therefore, it is not necessary to rotate plugs to maintain even electrode wear. You may wish to rotate top to bottom to minimize deposit build up."
 
Erosion Gauge

Pick up a Spark Plug Erosion Gauge to check when the electrodes are worn out. I have gone well over 1,300 hours on one set of Champion plugs and could have gone longer. The 5,000 ohm resistance is another thing to watch that someone else posted about. For me, erosion wear has been the limiting factor on spark plugs IF I do not drop them.

12-00791.jpg

Aircraft Spruce advertises here and they sell the above gauge. The image above is from the Aircraft Spruce web site.

Stop by the Champion booth at AirVenture Oshkosh when you are there. They were giving away the Erosion Gauges one year. I think it was Tempest that purchased Autolight plugs. They should also have an Erosion Gauge.
 
misleading info abounds.....!

Hey Gil, here's one place I read about the 'need' to rotate plugs! Why is there so much conflicting info out there? Either the polarity changes, or it doesn't! They haven't changed how magnetos work in the last few years have they?

http://www.aviationpros.com/article/10381828/aviation-spark-plugs

"Spark plugs should be rotated periodically to even out the electrode wear," Hansen notes. "Magnetos fire the spark plugs with negative and positive charges. The negative charge will wear the center electrode and a positive charge will wear the ground electrode. Just like rotating your car's tires, rotating your spark plugs will make them last longer by using up both electrodes."

and these are the...'aviation PROS' no less! :)
 
Special case

Hey Gil, here's one place I read about the 'need' to rotate plugs! Why is there so much conflicting info out there? Either the polarity changes, or it doesn't! They haven't changed how magnetos work in the last few years have they?

http://www.aviationpros.com/article/10381828/aviation-spark-plugs

"Spark plugs should be rotated periodically to even out the electrode wear," Hansen notes. "Magnetos fire the spark plugs with negative and positive charges. The negative charge will wear the center electrode and a positive charge will wear the ground electrode. Just like rotating your car's tires, rotating your spark plugs will make them last longer by using up both electrodes."

and these are the...'aviation PROS' no less! :)

Rotate them! Post #11 above -

"Four cylinder engines equipped with single drive dual magneto fire with constant polarity, therefore, it is not necessary to rotate plugs to maintain even electrode wear. You may wish to rotate top to bottom to minimize deposit build up."

- gives the special case of a single drive dual magneto, not the usual magnetos on our O-360 and O-320 engines.

The O-320-H models would fall into this special case.

The earlier Champion document says to rotate them and give a picture of one rotation sequence. That covers 99% of our RV engines.
 
Gil is right. I posted Reply 11 as I have an O-360-A1F6D with the single drive, dual magneto. So, that special case applies to me. Until this thread I didn't know that the plugs did not need to be rotated, so I posted that for the information of others. I apologize for not being more specific and therefore confusing the issue somewhat...
 
I have 2 sets of plugs for my plane and rotate them every 50 hours at oil change. Easy to do and takes the worry out of having fresh plugs. So far over 500 hours on the two sets (250 hours each) and still going strong. After cleaning and gapping the set taken out of the aircraft, I spray liberally with WD40 and store in a sealed sandwich bag in air conditioning.
 
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