"Unhappiness" degenerates...

[berger]

Hi Everyone,

After I checked the AeroCarb and added a provisional heat insulation to the gascolator (as per previous discussion on AeroCarb ice), I took to the air twice for over one hour each times, with a perfectly well running engine, despite very humid and mild atmosphere.
As a reminder, the engine has now a little over 350 hours and had a top end overhaul w/. conversion at 125 hours. Runs exclusively on Avgas 100LL.

After the two last flights, I, however noticed that the LHS exhaust pipe was covered with whitish deposit versus tan as normal. The RHS pipe was looking as normal, light tan.

The oil consumption which did not change significantly over the years is around 17 cl/h.

This morning in an attempt to take to the air, I pulled the prop through and noticed the following failures:

Cylinder #1: normal compression; pronounced noise "Ting"
Cylinder #4: good compression
Cylinder #5: good compression
Cylinder #2: NO COMPRESSION. Prop went through from #5 swing
Cylinder #3: good compression
Cylinder #6: normal compression; small noise "Ting"

To me, it could well be one of the #2 valves, but I cannot explain the "Ting" which appear whatever the rotation direction is. If the rings would be the failure, I think that the oil consumption would be increased, unless the piston skirt is broken as it happened to someone else.

Positive point is that it did not let me down while aloft, but on the ground and that my "homework" did catch it early enough.

Next move will be to look inside AGAIN to see what can be seen, before removing heads and perhaps more...

Any thoughts on the above?

Thanks!
Sosthène

Sent from a hard-wired health respectful computer

[cliffrunkle]

Here is a Youtube video of a Jab with the "Ting" Take a look. https://www.youtube.com/watch?v=22z4HvFkfbc And that Video is followed a little more in depth with this https://www.youtube.com/watch?v=9CkSQR2HTek And the series concludes with this video.
https://www.youtube.com/watch?v=9CkSQR2HTek Hope this helps.

[berger]

Hi Cliffrunkle,

Thank you for the links to the videos I saw back then but could not retrieve.

The last link with kind of an explanation is here:
https://www.youtube.com/watch?v=-ZC0wtjme9Y

I hope my Ting is less serious than that. Will investigate further within the next days

Thanks
Cheerio,