We all know the lousy oil filters for the M20 that come from India. For proper oil filtration, I have a cheap fix. Remove the fleece from the strainer; depending on the application, you may need to widen it slightly. Grind off the three tabs on the filter cartridge. Drill an 8.5 mm hole in the bottom of the cartridge. Load the strainer with the drilled cartridge first, then the second cartridge with the rubber facing down. This way, the seal sits on the seal. Now, as usual, put the lid on. These cartridges can also be used for oil tanks with screwed lids without any modifications.
