Boroscope images

Hopefully below you will see some images of the valves on my Lycoming O-360-A1A, bought new through Van's. First flight in August, 2002. Currently at 1392 hours.

The images were taken through the generosity of a Whitman Tailwind builder. This is a SnapOn Bk6500. Very nice!

This is my first attempt using a digital boroscope, so comments are welcome. As best I can tell, the surface of the valves looks okay. No green hot spots and the coloration seems even enough to me. Feel free to disagree.

My main concern is all the buildups around the valve seat edges. I presume this is lead and other fuel additives. Is this a concern?

Compression is in the mid-70's for all cylinders and the engine runs great. I typically run at 60% - 65% power. CHT's are normally 335 - 350F. Since this is a carburated engine, I run rich of peak, usually 50F.

I have not figured out how to post images, so I have included the Google Drive links below. Anyone with the link should be able to see the pictures.

https://drive.google.com/file/d/0Bx-KEMjH0x7mekNDbDktSVk3WXM/edit?usp=sharing

https://drive.google.com/file/d/0Bx-KEMjH0x7meDU3WXFkSHI3ZUk/edit?usp=sharing

https://drive.google.com/file/d/0Bx-KEMjH0x7mLVpOVldEM0kxYlU/edit?usp=sharing
https://drive.google.com/file/d/0Bx-KEMjH0x7mVVNxdVVsdHBoWjA/edit?usp=sharing
https://drive.google.com/file/d/0Bx-KEMjH0x7mY1l4S09kbmdkWU0/edit?usp=sharing
https://drive.google.com/file/d/0Bx-KEMjH0x7mcFdIanFuUmhVS28/edit?usp=sharing
https://drive.google.com/file/d/0Bx-KEMjH0x7md2xQamh4UEl6TFU/edit?usp=sharing
https://drive.google.com/file/d/0Bx-KEMjH0x7meGVwRDY3Z1NUbTA/edit?usp=sharing

Something to consider:

"50°F ROP is almost precisely the*worst*possible mixture setting from the standpoint of engine longevity. The maximum cylinder head temperature (CHT) and peak internal cylinder pressure (ICP) occurs almost precisely at 50°F ROP. So using the "recommended lean mixture" assures that your engine operates at the hottest, most stressful corner of its operating envelope..."


http://www.avweb.com/news/savvyaviator/savvy_aviator_59_egt_cht_and_leaning198162-1.html

Yes, I have seen that. I only run that setting when I am at 60% power or less. The reason for this choice is that is the leanest I can run without any roughness.

At higher power settings I use 70 - 100 degrees ROP.

He isn't doing any harm to the engine at 50 ROP if he is operating at 60-65% power as stated. For all we know he is in a hurry and up at 10K feet or whatever with full throttle, in which case 50 ROP makes sense. Worst case is he is burning a little more fuel than necessary.