Solar-driven engine dehumidifier/dryer

[Mooney-Shiner]

Hey, crew!

I finally got a minute to post my PIREP of home-made dehumidifier/dryer system for my IO360.

 I designed my system to run 15 minutes, shut down for 45 minutes. I found this to be a good work ratio to keep my crankcase dry (25 % relative humidity) here in South Florida. Also I installed the humidity meter probe(green line) in the return moist air line (marked blue line on the sketch). The dry air (orange line) gets pumped thru the oil stick tube, the return moist air (blue line) come back through the engine breather line.

List of materials:

Fuse box https://www.amazon.com/dp/B08XWQHMZJ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
Solar Controller https://www.amazon.com/dp/B075NQQRPD?ref=ppx_yo2ov_dt_b_fed_asin_title
Motor https://www.amazon.com/dp/B0D98KH74P?ref=ppx_yo2ov_dt_b_fed_asin_title
Humidity meter https://www.amazon.com/dp/B09V1P9921?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
Bottles https://www.amazon.com/dp/B09446XH8K?ref=ppx_yo2ov_dt_b_fed_asin_title
LiFePO4 battery 20AH: https://www.amazon.com/dp/B0CKLQVGG1?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_10
Solar mounting rack: https://www.ebay.com/itm/126310204673
Solar panel 100W: https://www.ebay.com/itm/124397245729?var=425269527294  

Desiccant: https://www.amazon.com/dp/B09TX3DNY5?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1

I hope this helps our community to stay away from those expensive SMOH because of the corrosion damage. Sorry for non-doctrinal schematic, I wanted to make something quick. 

Please let me know if you have any suggestions, I'm always looking to improve this system.

At some point I will also wrote my PIREP on the BlackMax saga which didn't work for me that well.

 

 

 

[dkkim73]

1. Diagram is missing the rat on a unicycle (Rube Goldberg joke)

2. How do you access the engine breather line?

Thank you for sharing. 

[Mooney-Shiner]

12 hours ago, dkkim73 said:

1. Diagram is missing the rat on a unicycle (Rube Goldberg joke)

2. How do you access the engine breather line?

Thank you for sharing. 

I used the plug similar to this (I don't remember exact diameter). I drilled the hole in it, and pushed in the tubbing thru it. I plugged the breather tubbing in the lower cowling. I used the earplug to seal the backup hole. I will take the photo next time I visit the plane.

https://www.lowes.com/pd/Hillman-0-8125-in-Black-Neoprene-Hole-Plug/3013260

Edited February 4 by Mooney-Shiner

[Pinecone]

You can buy pre-drilled plugs from scientific supply places.

 

[M Terry]

this is my set up: 12v bait well bubbler blows air through desiccant in an old pretzel jug, out via hospital suction tubing to the oil dipstick tube. air comes out of the motor via the crankcase vent. Runs intermittently, controlled by a electronic timer. powered by a bank of surplus BB600 ni-cad cells, that are charged by a solar panel on the roof of the hangar.

[Mooney-Shiner]

On 2/3/2025 at 8:11 PM, dkkim73 said:

1. Diagram is missing the rat on a unicycle (Rube Goldberg joke)

 

2. How do you access the engine breather line?

 

Thank you for sharing. 

 

Here is how everything plugs to my engine.

 

[Mooney-Shiner]

On 2/5/2025 at 12:37 AM, M Terry said:

this is my set up: 12v bait well bubbler blows air through desiccant in an old pretzel jug, out via hospital suction tubing to the oil dipstick tube. air comes out of the motor via the crankcase vent. Runs intermittently, controlled by a electronic timer. powered by a bank of surplus BB600 ni-cad cells, that are charged by a solar panel on the roof of the hangar.

Great work on the cost saving with using simple/surplus components!

I frankly surprised that more people don't use/build these systems. This kind of threads never get any significant interest.

[Pinecone]

I wonder what the actual air path is inside the engine.

[Mooney-Shiner]

4 minutes ago, Pinecone said:

I wonder what the actual air path is inside the engine.

Hopefully, entire engine is the path. But I'm thinking the dry air enters at the oil level (low) and then eventually exits thru the high point of engine breather. Hopefully, the dry air circulates all of the nukes and crannies (maybe even packing thru piston ring gaps?)

[Pinecone]

I doubt that happens.  Air takes the path of least resistance.

But having dry air in the engine should remove moisture due to diffusion.

[201Steve]

@Mooney-Shiner what’s the 10 second answer on black max? I just started using it curious what issue you had

[Mooney-Shiner]

1 hour ago, 201Steve said:

@Mooney-Shiner what’s the 10 second answer on black max? I just started using it curious what issue you had

I bought the BlackMax before going on deployment in 2023. Installed the the output into the oil drip stick tube, the humidity reader installed in the breather fitting at the top of the engine (Lyc IO-360).
Came back after 7 months to see 60% humidity reading. The device didn't function right due to dead cooling fan. Sent it back to manufacturer in November. The fan had quit and allowed the block to overheat. Manufacturer replaced the thermal element, temp ic and heatsink/fan assy.
Received it back and checked the proper flow level according to the manufacturer. The standard is air bubbles forming a "string of pearls" at the 3" depth of 2L water bottle. I was still getting between 50%-60% humidity.

In December, I sent it back again to Ohio, but it passed the manufacturer test and maintained sub-20% humidity on their test bench. I installed it back, but still was getting 60% RH in the crankcase. I decided that the culprit is my engine. So I pressurized crankcase with the mattress pump and used soapy water to find any significant leak areas on my IO-360, but none were found.

So I figured that the flow was not enough to keep up with humidity inside of my IO-360. I opened the Black Max and increased to max flow on the aquarium pump-looking pump. The RH was finally at 20-30%. A week later I discovered that the pump had quit and no longer pushed the air in my crankcase.

I showed it to manufacturer and received the replacement BlackMax (still in the box).
Overall, the manufacturer was pretty responsive, but I just don't have any confidence in the Black Max technology.

I decided to do an experiment. I took the 27 gal plastic tote. Ran the drying line from BlackMax inside there and installed the probe from the humidity reader. After 24 hours of operation, the humidity was at 60%. In despair, I installed basic make shift desiccant bead dryer (much simpler than one in my original post). To my surprise, within 15 minutes the humidity inside the tote became 15%.

Honestly, best you can do is build your own engine dryer where everything is clear and simple. I'm now getting 10-24% humidity in the crankcase.

How is that for 10 seconds?

[Mooney-Shiner]

I used an old pelican case to protect it from weather