Reducing Sport Cub oil temps

[Pete D]

This is an informational post regarding an option now offered by CubCrafters for reducing oil temps on the O-200 powered Sport Cubs.

All of the S1 and S2 Sport Cubs left the factory with the same 7 vane (row) oil cooler. Up until now there have been two different oil cooler plenums (Gen I and Gen II). With the larger, 9 vane oil cooler the Gen II plenum can be modified to fit or a new Gen III plenum can be purchased.

We generally see a drop of 15 to 20 degrees when the larger 9 vane oil cooler has been installed. We have the oil coolers available for $299 and the Gen III plenums for $98, or $397 for the kit. We can install them here, they take about 3 hours labor. Below are some pics comparing the larger oil cooler and larger plenum.


Gen I installed.jpg
"Standard" installation as seen on most S2 Sport Cubs. 7 vane oil cooler with Gen II plenum.

Gen II installed.jpg
Upgraded to 9 vane oil cooler with Gen III plenum.

1005001039.jpg
Gen II plenum (top) Gen III plenum (bottom)

1005001019.jpg
Standard 7 vane oil cooler on left, Larger 9 vane oil cooler on right

1005001020.jpg
Another comparison picture of the two oil coolers.

Several customers have already installed the larger oil cooler, if you are one of them please feel free to comment on your personal experience with this option.

[Pete D]

I have been reminded that any S-LSA aircraft will need a letter of authorization from the manufacture (Cub Crafters) to do this modification. E-LSA aircraft are good to go. This will be included when you purchase the parts if needed.

Pete D

[reileyr]

Pete, who is supplying pistons and rings? Compression ratio?

[Pete D]

Pete, who is supplying pistons and rings? Compression ratio?

The work is being done by Aerosport Power in Kamloops, BC. The same folks who assemble our CC340s for us. I believe they are supplying the parts.

Compression ratio on a stock O-200 is 7.1:1. The compression is increased by putting a set of (modified) C-90 pistons in. I'm not sure what the final compression ratio will be but its a significant difference.


Pete D.

[randylervold]

9.0:1 for the compression ratio on the "performance package". The owner Pete is referring to is having additional work done.

[Pilawt]

#62 (S2) still has the original oil cooler, but when CC installed the larger plenum last June there was an immediate 10-degree drop in oil temps across the board.

[Steve Hamblin]

Good point-the original design had a very thin plenum (about 3/4" thick). Updating to the newer plenum (a couple inches thick) will certainly result in better cooling. This larger oil cooler and it's associated plenum cools even beyond that.

Steve

[couleeone]

Howdy from Geo, I was having heating problems last summer especially training students during maneuver's that require a lot of climbing. Pete installed the new larger oil; cooler and gen III plenum. I saw an immediate 20 degree drop under the same circumstances. I feel more comfortable with the temps especially since I will be flying in the AZ desert for the next several months.

However I would like to see further improvement in cooling, perhaps by increasing the bottom exhaust opening to let more air flow through. I know Diana Votaw experimented with a larger opening and apparently it improved the cooling.

Pete did I get the CC letter for the oil cooler modification?

Geo

[Pete D]

George,

Ethen has informed me that all of the larger oil cooler installs that we have done or shipped parts for got the Letter of Authorization. I can double check with him or Steve about your specific airplane but that should include yours.

Pete

[Pokette]

Is there some actual test data for the new oil cooler?
I installed the new plenum and did NOT see a 10 degree drop. Mine showed no improvement. I only have oil temp and oil pressure. Is there anyone out there with more engine instrumentation who can provide some numbers?
Diana