Ron,

 

Niagara Thermal makes the OEM coolers that come on the TCM engines.  The IO-550N uses a different model than just about every other TCM big block engine.  TCM has used (in the engine mounted style cooler) the #654580 cooler on IO-520s and TSIO-520s and other IO-550s, going back some thirty years.  The Niagara Thermal web site makes mention that they do work for TCM but they don't list any specific part numbers.

 

The cooler on the IO-550N is the #654585, same core, but different vernatherm and routing of the oil.  Some IO-550N ES pilots have had high oil temps compared to some of the builders who've been flying for a few years with the IO-550G, which came with the #654580 cooler.

 

To keep this short, the #654585 cooler doesn't seem to work as well as the older design #654580 cooler.

 

Positec has a direct replacement for the #654585 and #654580 coolers.

 

Aero Classics has one for the #654580 and is in final PMA approval for their #654585 design.

 

Since we're experimental, we don't have to use the exact replacement, we can switch designs if we want to.

 

Of course none of this applies to a Lycoming installation!

 

Mike Easley

Colorado Springs