SonexBuilders.net

Fellow Jabiru owners,

I've started collecting oil analysis results for my engine and any other owners that I can find online (there's not much posted out there). I'm hoping to promote discussion and share results. Here's what I've got so far.



Jeff

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(Here's the raw data, but it doesn't display correctly without tables...)

Aircraft,604CM,604CM,Unk,Peter,Peter,Peter
Hrs TT,170,195,100,300,499,600
Metal,PPM,PPM,PPM,PPM,PPM,PPM
Aluminum (Al),23,16,25.1,17.9,19.9,19
Iron (Fe),63.6,54.24,186.1,143,66,71
Copper (Cu),17.31,19.21,11.9,10.3,7.9,10
Nickel (Ni),2,2,1.6,2.1,1.1,2
Chromium (Cr),4,4,8.9,14.6,4.6,5
Silver (Ag),<1,<1,0.1,0,0,0
Silicon (Si) ,18,23,10.6,-,-,-
Magnesium (Mg),-,-,1.7,0.2,1.1,0
Lead (Pb),-,-,4396,6173,2882,829

Here's mine.

I have no idea what happened to my last one. I got it in an email and now I can't find it. Just changed my oil last weekend and I have a new sample I need to send out. I'll post the results when I get it back.

Here are averages from my last three checks at 25 hour intervals...

Iron 37.2
Copper 4.3
Nickel 0.83
Chromium 3.6
Silver <0.1
Magnesium 0.2
Aluminum 10.3
Lead 3241
Silicon 8.1
Tin and Molybendum were less than 0.1

Finally remembered to chase down my last oil sample. Ended up in my junk folder.

3300A
Hours 279 TT Maybe 40 since OH?

Al : 41
Fe : 199 (crap!)
Cu : 6
Ni : 4
Cr : 13
Ag : 0
Si : 13

I'm a little concerned but I'm not going to panic until I see some sort of trend.

After 20 years of oil analysis on a Cont. O-200 every 25 hours, I wouldn't be too concerned with a high iron content at this point. If this is a 25 hour sample, your engine was still breaking in during the beginning of the sample. It's most likely showing the piston ring, cylinder bore wear during break in.. A compression test 80/? will confirm it. The trend is the important thing to watch. If a spike in one of the components happens after a long run of steady readings, then you should be concerned. I once had a stuck valve repaired and all the readings went high on the next sample, and it took another hundred hours for all the "dirt" to work it's way out and get back to normal.

I'm not freaking out yet. Im going to run another 15 hours and pull another sample.

Glen, As you stated, not time to freak out yet.

However, with all the emphasis on not running too lean and getting high EGTs, it is not good to run too rich either as that washes oil from cylinder walls.

Another thing to consider: In one of my discussions with Ian Bent (CAMit) he stated that he never thought the prescribed break-in procedure for Jabiru was correct, and does favor babying it a bit. Avoid prolonged periods of full power, especially at low air speeds. The cylinder walls are thin and steel does not conduct as well as aluminum, thus easy to quickly get hot spots on cylinder walls where shielded from cooling airflow, and that breaks down the lubricating properties of the oil leading to increased cylinder wear.

Obtaining one of those inexpensive flex head bore scopes (Vividia VA-400 bore scope) Can help spot problems and give piece of mind when none found.

David A. Sonex TD, CAMit 3300 #0004

I consistently get a high EGT on #6 on climb. I honestly believe it's the location of the probe though. The aerocarb dialed in pretty well. Engine has plenty of power. Everything looked good when I adjusted the valves and replaced the plugs. I'll be breaking open the filters from the last two oil changes today to take a peek.

vwglenn wrote:I consistently get a high EGT on #6 on climb. I honestly believe it's the location of the probe though. The aerocarb dialed in pretty well. Engine has plenty of power. Everything looked good when I adjusted the valves and replaced the plugs. I'll be breaking open the filters from the last two oil changes today to take a peek.

I too got high egt readings on 6 in climb out with the aerocarb. I think its due to #6 being closest to the carb and the aerocarb not doing a great job at atomizing fuel so it goes lean. My Rotec has a spray bar and seems to do a better job at atomizing. #6 doesn't go nearly as lean on climb for me now.