This is an update on the information about the STC'd replacement for the accessory drive bevel gears. After getting the information from Jim Hickman, I contacted Niagra Air Parts. They were just getting FAA approval for their fix for the bevel gear problem.
Their fix is to replace the "TEE" drive gear box with a straight drive gear box. The "TEE" drive allows the installation of two accessories (usually the vacuum pump and a hydraulic gear pump, or the vacuum pump and an airconditioning compressor) to be mounted at right angles to the centerline of the engine. The straight drive accessory case allows only one accessory, mounted in line with the centerline of the engine. If you don't have two accessories (I onoly had the vacuum pump on my engine), the straight drive case will work. This is the same arrangement as on the TSIO-360's used on the Seneca.
While the straight drive is standard Continental design, it is not part of the Type Certificate for the Skymaster. This is why Niagra Air Parts is getting the FAA approval as an STC for the substitution. (I understand they have it now.)
UNFORTUNATELY, this fix wouldn't work on the front engine of my 73 P337. There was not enough room behind the starter adapter to mount the vacuum pump. The engine is too close to the firewall to allow enough clearance to add or remove the pump. I assume this is not the case in other models, but I don't know for sure. I also don't know if this fix would fit in the rear engine compartment.
The replacement bevel gears are about $400 EACH. It sure would have been nice to get rid of them.
Mark
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