Description:

The IO520 and IO470 Rear Alternator engines are referred to as Sandcast Engines.

They share the same engine cases, crankshaft, lifters and almost all internal components. IO520 versions simply have a larger cylinder bore than the IO470.

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This STC allows installation of IO520 cylinders on your IO470 engine. Same thing that Continental did when they certified this engine as an IO520 used in many Cessnas and other aircraft. They also certified a 550 version using the same crankshaft configuration with a slightly longer stroke.

 

Our airframe STC conversion applies to these aircraft:

 

Bonanza:

• J35 through P35, G33

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Baron:

• 55 through B55

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Cessna:

• C-310C through C310Q. 

 

Our engine STC covers the following engines:​

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• IO470-C, D, E, F, G, H, L, M, N, R, S, U V, VO

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Modifications for Conversion:

• 470 case is bored to accept the larger diameter IO520 cylinders. Piston cooling oil nozzles if not already installed

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• 520 cylinders of your choice may be used

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• 520 counterweights are installed on the existing 470 crankshaft

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• Fuel injection divider at the top of the engine is replaced with the 520 version

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• Fuel controller is set up for the IO520BA or BB fuel flows pre SID97-3

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• New cam shaft gear is required and will be in compliance should this become an AD.We also recommend the larger IO520 crank shaft gear

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• We highly recommend D'Shannon baffles.

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• Same propeller is retained on Barons.  Single engine conversions are limited to Hartzell propellers. MT has a composite model flying on one of our conversions.

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• Engine data plate is replaced per the STC

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• TBO becomes 1700 hrs

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• Flight Manual Supplement update

 

Bottom Line:

This is the most economical performance increase to your IO470. It makes a lot of sense to do this when overhauling an IO470, increasing the displacement by installing larger cylinders.

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Increases TBO to 1700 hours.

 

Gain IO520 performance at wide open throttle settings

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Cygnet provides the STC permission and data for your engine shop to convert your engine.