After we had ordered the new TMX-IO-320 engine from Mattituck for our RV-3, I got serious about doing dome detailed reading on the few RV-3 Web sites that we reference, particularly Randy Lervold. As I was reading the details, I suddenly remembered that he had some difficulty with the lower cowl configuration for his IO-320, and sure enough, he had detailed the problems for us in this write-up:
http://www.romeolima.com/RV3works/Airframe/airframe.html#Finish
The basic problem was that the O-320 cowl did not have room for the IO-320 throttle body and FAB ? what we needed was an O-320 cowl with an O-360 snout. I called Van?s to talk about this, and found there were two options ? buy an O-360 snout, cut our snout off, and glass the new one in place, or have the cowl made with the O-360 snout from the start. It turns out that this is actually an available option from their fiberglass shop, and it was easy to obtain. Furthermore, it happened that Tony Partain was headed our way, and could exchange the cowls for us (we had the wrong one, as the previous owner of our kit had bought a standard O-320 cowl).
Before we sent the old cowl back, I stood the two lower cowls together in the hangar for some comparison photos. It is fairly obvious which one has the bigger snout!
Side view ? IO-320 cowl on right, O-320 cowl on the left:
Front view ? IO-320 snout (left) is also wider:
Paul
http://www.romeolima.com/RV3works/Airframe/airframe.html#Finish
The basic problem was that the O-320 cowl did not have room for the IO-320 throttle body and FAB ? what we needed was an O-320 cowl with an O-360 snout. I called Van?s to talk about this, and found there were two options ? buy an O-360 snout, cut our snout off, and glass the new one in place, or have the cowl made with the O-360 snout from the start. It turns out that this is actually an available option from their fiberglass shop, and it was easy to obtain. Furthermore, it happened that Tony Partain was headed our way, and could exchange the cowls for us (we had the wrong one, as the previous owner of our kit had bought a standard O-320 cowl).
Before we sent the old cowl back, I stood the two lower cowls together in the hangar for some comparison photos. It is fairly obvious which one has the bigger snout!
Side view ? IO-320 cowl on right, O-320 cowl on the left:
Front view ? IO-320 snout (left) is also wider:
Paul