A couple of weeks ago I got to join with another local EAA chapter which had arranged a tour of the GAMA Injector operation just south of Ok City in Ada, OK.  Their specialty is selling their own replacement injectors for Lycoming and Continentals and they balance each one to the particular engine in order to allow lean of peak operations, etc.  The part I found interesting was what they learned about exhaust systems from fabricating numerous ones and running them in their test cell. 

 

From their experience their really were two failure points with the first being between 15 and 19 hours and the second being about 95-110 hours.  The first failure point was usually due to vibration or installation issues while the second was usually a from the materials not being as robust as needed to survive the long haul.  If their exhausts made it past the 110 hr. point they were very confident they would go for a very long time.

 

On a similar note, are any of you using slip joints with springs (or without) when you fabricate your exhaust systems? 

 

I also have a conversion concepts engine mount and the tubing on left side interferes with the manifold that came with my 13B and it will require me to run two distinct exhaust manifolds instead of the Racing Beat type that is a continuous manifold.  Are there any special rules of thumb / lessons learned when running two distinct manifolds like that?

 

Thanks for any insights / opinions.

 

Doug Lomheim

RV-9A, 13B

OK City, OK