Leonard Ellis wrote:
: We're nearing time to overhaul the Lycoming O-320H2AD (6210 hours since new)
: in our C172N. This will be its 3rd major overhaul and we're interested in
: learning about the experiences of those who upgraded to the O-360.
: Specifically, the changes you found in performance, impacts on range, or
: other relevant information including recommendations on where to get it done
: will be appreciated.

We've got a Cherokee 140 that was upgraded to a fixed-pitch 180 before we
bought it. Aside from the outright cost of the new engine and STC paperwork, it is a
no-brainer as far as performance. The "impacts on range" argument is silly, really...
just because you have a larger engine doesn't mean you need to run at higher cruise
powers. I run our Cherokee 180 at 65%, which is about the same as 75% for a 150/160.
Same fuel burn, but cooler engine, and you got more power when you need it.

Where the decision gets more difficult is whether or not to go CS prop or not.
For the most part, with fixed-gear I'd say it's not worth it. It won't buy you much
speed (if any). It WILL buy you faster climb and more load hauling, but most STCs
I've seen do not allow a gross weight increase with a larger engine. I know ours does
not. Also, the CS prop is expensive, more maintanance prone, and adds quite a few
pounds on the nose of the plane.

-Cory


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* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
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