Rate my Spark Plugs

[RudiGreyling]

Morning Aviators and Mechanics,

OK so I did my first 100 HOUR engine service on my RV this weekend.

Tacho time = 100 Hours, Hobbs = 125Hours.
(Why the difference?? Because the Dynons normalize engine operating time to Cruise RPM of 2500RPM, so if you taxi and idle the engine time goes by slower, Nice hey!) It basically mean you are really getting slightly more time between services, becuase the engine is not doing a lot of work idling and taxing. In my specific case it meant I got 25 Hours extra in the first 100 hours.

I am still learning my way through the Lycoming engine specifics, So to the experts, this is what I found, I think it is pretty good???
I rechecked the timing, for the first time since new (125 operating hours) and it was out by 2 degrees.

I was really impressed by my spark plugs condition after (125 operating hours). Now remember I started running LOP at 25 Hours, after the new engine settled, and only during the cruise phase (so these plugs has 25h ROP and 100 LOP on them) and also remember that I am running MOGAS (unleaded 95 octane) during the cruise phases of the flight. (Avgas is for critical portions of flight, take-off, landings, Aeros, and bad terrain). My engine is a fuel injected 180HP XP-IO-360, standar Mags, with CHT and EGT probes on Each cylinder, and a Dynon that allows easy LOP operation!

I took these picture with my cell phone at very close proximity and I think the plugs are very good!
The first picture is straight out the engine, you can only see some very small deposits on the plugs.


The deposits are very loose, and with the wipe of a clean rag it came off, looking almost good as new in the 2nd picture.


Needless to say the plugs went back into the engine ready for another 50 hours of service.

Now remember I am still a 'lycoming' newbie, but it looks like my LOP and Unleaded Mogas is doing the trick looking at spark plug health.
What do you think and how does it compare to your plugs after 100 (125 hours)?

Regards
Rudi
PS: I will check the blow by's in 2 months time when it is time for the annual, I still need to buy my own intrument or borrow one.

[pierre smith]

....the coloration looks good. In our NASCAR race car series, they shut the engine off while near full power and coast into the pits for a spark plug/mixture check. The reason for using this method is so there is no idle time, during which the mixture is richer, darkening the plugs. If you can possibly avoid any long idle/taxiing, your check would be even more accurate.

Regards,

[osxuser]

Keep doing whatever you are doing. A+++ for engine health from this mech. Any deposits down deeper inside? Usually lead builds up at the bottom first. Either way, LOP and Mogas will prevent most lead buildup.

[Bubblehead]

Rudi - what spark plug heat are you running?