Borescope inspection of the cylinders and valves have become a regular part of my annual maintenance and engine inspection. In fact, I believe it is a wonderful way to assess the health of the engine. I use it in conjunction with oil analysis and head bolt tension check as indicators that the Jabiru is running well internally and that no problems are developing unseen. I posted the results from the 2018 inspection, and this creates a running log of pictures inside the engine to track changes over time.
I continue to be impressed with the Vividia Ablescope VA-400. This model requires a separate device to serve as the monitor (using a USB cord interface). Many Android phones have USB port capabilities, but the iPhone does not and requires a separate wifi adapter. Since I have an iPhone and didn't want to buy the adapter, I use my laptop to capture pictures. It's not as convenient as the phone, but works fine.
The results of the inspection showed (again) all cylinders and valves were in good condition. The engine has 360 hrs of use, running a mix of premium car gas and 100LL. The piston tops show a bit of crusty white deposits that appear to be a few thousands of an inch thick. These deposits were soft and easily scraped away. In places you can see scratches in the deposits from the probe I inserted to ensure the piston was all the way down. The probe easily scratched the crusty surface deposits, and the pictures make it look like damage to the pistons, but it isn't.
I've been running more auto gas, as well as using more Decalin additive with my 100LL to scavenge the lead. You can see a few indications of lead in a few spots (green-ish or silver color), and once again the #5 cylinder shows more lead accumulation on the valve and spark plugs. I attribute this to the overly cool temps present in that cylinder. It was better this year than last year, and I'll continue to monitor over time.
These pictures show the importance of leaning in flight. My engine looks OK, but I might need to lean a bit more at times to help burn off the deposits. My head temps run so cool now that I need to help this out from time to time.
NOTE: photos link to full size image