if you operate at high power with a flat lifter the corresponding valve will eventually fail, usually about 100hrs afterwards.
If you are lucky you will get a low compression reading before failure. this is a photo of the valve that first gave us a clue as to what was happening at some USA flight schools back in 2002. It turns out a well known representative of a major aircraft manufacture was giving well intentioned, but wrong, information on how to get all the dirty oil out of the engine. 3 in-flight failures resulted.
IF YOUR OIL IS SO DIRTY THAT YOU FEEL YOU HAVE TO REMOVE EVERY LAST DROP THEN JUST CHANGE IT MORE OFTEN!
Im not saying your valve will fail if you do an incorrect oil change, most of the time the lifter pumps up OK by itself. But it does add a risk. Why not just follow the written procedure?
I was very saddened a few weeks ago to hear of another large OEM preaching the very same wrong-oil-change information, at a OEM training session in Europe.
4exhaustvalveinsideview.jpg (You do not have access to download this file.)
