SOLUTION #1: Challenger Lifetime Oil Filter - Never buy an oil filter again! $315 to fit the Skymaster
https://www.aircraftspruce.com/catal...clickkey=38453
https://kandpengineering.com/technical-information/
SOLUTION #2: Install automotive filters that fit perfectly (and do the same or better job of filtering) - this comes from Beechtalk.com, where they have the same issue with their IO550's:
The Donaldson P169071 and Lifeguard LF3487 have outstanding filtration properties and utilize top of the line synthetic media for finer filtration than conventional paper media and could be seen to have the same thread size and dimensional equivalent of the CH48109 filter. It is believed that Donaldson and Fleetguard/Lifeguard are made by the same manufacturer.
Donaldson is about $18
https://www.dieselequipmentinc.com/products/p169071
and Fleetguard may be found for even less
https://puredieselpower.com/products...er-lf3487.html
The WIX functional equivalent to the LF3487 is PN: 51515 but may only use conventional paper media (do your research on that), as it is priced at about $6 each
https://www.amazon.com/WIX-Filters-5.../?tag=btalk-20
A case of 12 here for $50
http://www.discountfleetsupply.com/wix51515mp.html
K&N makes one that looks like a Champion - it has the hex nut on top and has safety wire holes. Not sure which model, post if you find out. Maybe this one?
https://www.summitracing.com/parts/knn-hp-2004
SOLUTION #3. Use a Tempest AA48109 (If you can find one). They are now LEGAL for the IO360 and TSIO360: See advisory Letter attached. This filter is taller, so it may not fit???
KEEP 'EM FLYING BOYS! DO WHATEVER YOU HAVE TO DO TO KEEP THAT BIRD IN THE AIR!