Actually I was referring to comparing the F4F and the Spitfire but it is quite possible to make unwarranted assumptions on too little data.
Perhaps the British did screw up but the Spitfire used an updraft carb and had it's air intake on the bottom of the nose, not an ideal location for dirty conditions. The P-40 with Allison used down draft carb and air intake on the top of the nose. P-40s in North Africa needed with Allisons needed significantly fewer engine replacements than P-40s with Merlins (Low air intake) flying from the same or nearby air fields.
The Zero used an air intake at the top leading edge of the cowl. Luck or good planning? Or shortest distance to the down draft carb?
A number of Japanese aircraft had overheating problems due to too small openings in the cowl, testing planes in Japan's home climate doesn't prepare them for use in the tropics.
Without knowing actual times between overhaul's or replacement for the planes under consideration and knowing both the "normal" expected life and the life in difficult conditions ( how much dirty conditions shortened life) we can read too much or too little into accounts of shortened engine life or the need for filters.
With replacement engines/parts having to come from England trying to ensure that the engines lasted as long as possible was probably the right decision.
Perhaps somebody does know if the Japanese suffered shorter life for their engines in dirty conditions or perhaps it is better said, just how much shorter was Japanese engine life than "normal" conditions and what they did about it. Internal filters? Dirt trap in the curve leading to the carb? accepting shorter engine life and providing (or trying to) extra engines?
Apparently the Spitfires that went to Australia were predominately fitted with Merlin 46 engines (?) and while this gave better high altitude performance than the Merlin 45 it gave less power at low and medium altitudes and and for a period of time in question was limited to 9lbs of boost?
With tropical equipment and the Merlin 46 engine the Spit V may have been 1 min and 20 seconds slower climbing to 20,000ft than a MK V with a Merlin 45 without tropical equipment.
Perhaps the Zero was better in certain locations ( pilots were more likely to be combat veterans) but saying the Zero was better than "the vaunted Spitfire, which always ranks in the top 1, 2 or 3 in greatest interceptors when they have a poll" when the Spitfire in question was about the worst performing model in 1942 and "polls" often only consider the best models (MK XII with Griffon engine was being tested by the Air Fighting Development Unit at Duxford at about the same time the Australians were trying to remove the Vokes filters from the MK Vs). This also rather shows the disconnect between what the RAF was using at home and what the Squadrons in the far east were using. Mk IX Spitfires leaving the factory in June of 1942 while the Australians were using MK Vs well into 1943.
See this website for more information:
http://www.darwinspitfires.com/index.php?page=articles