The International Cessna 170 Association

I finally got sick of constantly clogging bracket foamies
So I installed a Donaldson air filter on my O300.
Wow! I am impressed. I picked up about 30rpm static. By the time I was airborne, I was looking at 2500 rpm where I used to see 2375 to 2400. I could keep 2500 rpm during through a 70kt climb.
In straight and level with wot I was seeing 2600.
Never saw these numbers before but I am very happy. Cheapest performance gain you can buy and I recommend it so far.

Dan B

Can you share info on the part number of the Donaldson air filter and where you can get it? Does it take a STC?

Dstates,
It is P107172
No STC as I am decertified but I wouldn’t imagine this would require an STC either. Seems like changing oil filter brand or nav light brand. Who knows though

Dan

Donaldson’s brochure says they are FAA-PMA for dry filters. No STC required.

Aircraft Spruce has both Donaldson and Tempest air filters, just for comparison

I assumed that the Donaldson filter used a paper medium and therefore needed to comply with AD 84-26-02. But that is not the case; both the Donaldson and Tempest filters use a synthetic medium. That AD does not apply to either of them.

Doesn't really matter since Donaldson recommends replacement after 3 years or 500 hrs.

I’ve never seen a Brackett filter clogged. What do you see?

Brackett filter elements are saturated with a sticky/oil “wettant” to increase it’s effectiveness over plain paper/cellulose/synthetic corrugated filters. The problem many owners experience, especially operating on dusty/dirt/turf runways is a fast build-up of dirt on the element. Sometimes it’s quite visible…and eventually it will result in some degree of air-losses.

Most operator/owners fail to properly install the Brackett element…. as when first received…the element is simply installed as-recieved…. But the foam element should first have the excess wettant removed. An easy way to do this is to place it between several layers of paper-towels and squeeze the extra wettant out…before installation.

(Another thing you should do while the old element is removed….is to use WD40, LPS-1 or something similar and a towel or rag to clean out the framework of the Brackett Assembly of collected dirt. While in there..grab a flashlight and visually inspect the screen-backing…and the entire sheet-metal air-box for loose hardware or other damage …. Before installing the new (properly wrung-out) element. You do NOT want any loose metal objects to get sucked into your engine intakes. This should be done Regardless of which Brand air filter you have.

I like Brackett and will continue to use it, but I squeeze out the excess wettant…and I am not afraid to spend another ten-bucks to keep a spare element on-hand for mid-year replacements. They’re cheap enough to replace them more often than other brands, IMO.

<edit> I have great respect for Donaldson as a filter mfr’r. They make good products.

Anyone know the difference between the Donaldson and the Tempest? Is the tempest just a Donaldson clone? Recommend one or the other?

My K&N might not be up to snuff since I'm seeing low level silicon levels in the oil changes nearest to some desert camping trips.

An issue I discovered with Brackett filters has to do with age. Brackett air filter elements have an expiration date shown on the package. They have a course mesh foam side and a fine mesh foam side. The fine mesh side goes toward the engine, the final filter before the carb.

I bought a bracket filter element in 2017 and kept it sealed in its package in my parts locker until I tried to use it in 2023. The expiration date was 2018, 5 years earlier. When I opened the sealed package, I found the fine mesh side of the filter had disintegrated into small particles of foam which crumbled away when touched. The fine side goes toward the engine so if it crumbles and goes thru the wire mesh, next stop is the engine.

The course mesh side appeared to still be in good shape but obviously, I did not use that element, I installed a new one with a current expiration date. I change the filter element at each annual so from now on, I won't install a new element unless its expiration date is past the next annual date.