Problem with the Challenger which I find out after I bought one for my
io-540 is no wrench fits the lug.

Challenger sucks. We bought one and found the same thing -- no wrench in my
tool box fit the lug.

Then -- worst of all -- the thing is made out of a much heavier-gauge metal
than the Champions. While at first this seemed like a good thing, it made
cutting the filter open to inspect the filter damn-near impossible.

In fact, it destroyed the cutting wheel on my filter cutter, requiring that
I buy a new one. The two bucks I saved was more than lost in that expense,
plus the extra time involved.

Since then, it's only Champions on my O-540.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"