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What you should know about the moisture in your engine that causes corrosion on your tappets and cam lobes

CFItom said:
I can’t seem to find a website for this unit!
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I have one and use it 24-7. In Michigan the humidity requires dry air in the engine in my opinion. After shut down I hook the system up and you can see visual moisture in the clear tube coming from the dipstick. I just pop the inlet to the silica out of the container for about 15 min then put it back in when I am ready to head home. The owner of http://www.rbaviation.com/ is a really nice guy.
 
wirejock said:
Yes. Nice someone keeps track. Yes. I have a roller. I don't see how a dryer could harm my roller tappet engine though.
Someone asked how to build one. No specific person addressed. I answered. I will recuse myself.
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I didn’t know that basically all Lycoming engines new or factory overhauled since 2007 are delivered with roller cams. It’s game changing. It goes from sliding friction to rolling friction which is an improvement of a factor or ten, maybe a hundred. A analogy is tire wear rolling vs skidding. There may be good reasons to dehydrate your crankcase but roller cam/lifter spalling probably isn’t one of them.
 
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Mikeyb said:
I didn’t know that basically all Lycoming engines new or factory overhauled since 2007 are delivered with roller cams. It’s game changing. It goes from sliding friction to rolling friction which is an improvement of a factor or ten, maybe a hundred. A analogy is tire wear rolling vs skidding. There may be good reasons to dehydrate your crankcase but roller cam/lifter spalling probably isn’t one of them.
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Roller tappets stop the usual wear related spalling issues, but a roller cam can go rusty just as easy as a slipper cam. And they do go rusty, too.

Internal corrosion isn’t also just a matter of the cam and tappets, those parts are cheap. At overhaul, corrosion on the rods or crank can cost you many thousands of ((insert currency here)).
 
While I'm on board with having a dehydrator on my engine someday, I did see commentary one time (don't remember the source), that dehydrating the internal moist engine air only condenses the nasty, corrosion-causing acids and chemicals onto surfaces and could accelerate corrosion. The post-flight internal engine air environment must be open-loop purged (quickly) first before a close-looped dehydrator is installed. (??)

🍿
 
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