I haven’t got my plane yet so not exactly sure how the oil cooler is situated but on my Husky there is a gate valve controlled from the inside that works great. For now I’ll probably do the tape thing. Lots of interesting ideas thanks. Can’t wait to get my plane and join the Maule family

I have a few pictures of my set up. The cooler shutter is on my M6 but works on my MX7-160 the same way only in the top aft position. The cowl flap is on the MX7-160. https://www.dropbox.com/sh/b1q7ruqyu1ln ... CUKha?dl=0 I think you can get both through Aircraft Spruce or directly from https://antisplataero.com

Most, but not all, of the mods that I am familiar with were done on the west coast using the 540 260hp oil cooler drawings from Maule and a well designed and fabricated cable controlled flapper type valve built into the plenum in front of the cooler. Adapting this system to the 540 235hp engines requires an FAA field approval. The fellow who did most of these is a member on this site. He ask me awhile back not to share pictures of his work, which I will of course respect. I spoke to one of the guys at Maule a few months ago about my cooling problems and they acknowledged that they were aware that a number of people have complained of a similar situation. I was told that they were talking to there FAA contacts about adapting the 260 hp oil cooler system to the 235hp engines, but nothing was said to me that would indicate it was right around the corner, as everything FAA related is now harder, slower, and more expensive than in the past.

Hi Montana and Hale,
Montana, thank you for the photos and links, I will show them to my Engineer. I had not heard of Anti Splat Aero before.
Hale, thank you for the information, I will telephone Duane, perhaps another voice calling the Factory might help add impetus.

The AntiSplatAero oil cooler shutter looks interesting. I would have to measure my oil cooler to see if it will fit. I have to wonder if the end result would be more effective than just putting some foil tape over the oil cooler inlet screen. Is it worth all the time and cost of a field approval?

The early O540 J and IO540 W engines came from the Maule factory with a blanking plate across the top third or so of the oil cooler.
Not adjustable of course but strips of silver construction tape were easily applied and removed on the O540 J.

Thank you Andy and Jeremy...
Blanking the oil cooler with silver speed tape is my current method during winter.
However, I rather liked the elegance of the dedicated oil cooling system on the 260hp Maules described by Hale.
If it were a Factory supplied Mod, implementing it here would be easy. As a 'Field Approval' adaptation, I fear my Engineer would have his work cutout.

What are the typical oil temperature on a 260 in summer hot days (say 115F) and winter cold days (say 10F). Do you feel the 20006A radiator is properly sized or ideally would you prefer a slightly more cooling capable unit for summer and flap valve for winter days?

Hi Freedom, best to go with the 'Lycoming eng operators manual' (from Lycoming) re the temperatures.
The 260 does tend to run hotter than the 235. Maule fits a different oil cooler and also a NACA scoop to direct air through the cooler.
Baffling fit is important and be sure the front cylinder baffles are upward.
Sometimes cabin cool air is run from front of bottom cowl to firewall valve and is routed above the intake tubes under the cylinders, this can impede cooling airflow through the cylinder fins.
The 260hp right exhaust is pretty close to the cowling on right side and if its carbon fibre cowl, it can heat stress and crack at the junction of cowling to air egress venturi scoop.
That area should be covered with heat reflective silver tape.

I’ve the Maule naca setup, but I’ve retained the original oil cooler that came with my engine to try and see if it would be seized also on the maule but on the flight test it revealed to be too small.
So will now install a new one with the naca setup. Now I can install the original one, or same size as original but higher efficiency that would cool it down a bit more in summer.
I have anyone installed a flap door on the cooler to control the temperature. So given the possibility, should I go stock or high efficiency?

I don't know of an adjustable door with the naca intake, so don't know which cooler to use except the original 260hp Maule cooler. In very hot days it would be good to get more cooling though.

I am currently getting my 220 Franklin overhauled. I would like to fabricate an adjustable oil cooler vent to keep the oil at optimum temperature. Does anyone have a 337 for a field approval I can use for reference. I am particularly interested in the anti splat oil cooler vent. Any tips or advice would be appreciated.
Thanks.