---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Mon 01/12/04: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:09 PM - Re: Alternate engines (Gary Casey) ________________________________ Message 1 _____________________________________ Time: 08:09:16 PM PST US From: "Gary Casey" Subject: Engines-List: RE: Alternate engines --> Engines-List message posted by: "Gary Casey" <> As someone else mentioned, with a good aftermarket aluminum block you can go for displacements over 600 cu. in. if you like. I would stick to about 500 as the components get rapidly more expense going much beyond that. The key word in my choice was "direct drive" and that pretty much forces the engine to be mounted inverted, although a few have been mounted "right-side" up. In my version the lightweight prop would be mounted directly to the crank. I think the crank is strong enough as the main bearing diameters are larger than in the Lycoming IO-720. I would not take the risk of hanging an aluminum prop on it, though. With the prop mounted on the crank the cowling will be forced to have a good-sized chin, but not as bad as any Bonanza. Why direct drive? Light weight, low cost, better durability and reliability. A direct-drive big block turbocharged and running at 2700 can produce more power than any small block and will do it with little strain. The manifold pressure will have to be about 50 inches, but that's not much for these engines. The complexity of the turbo system is easier to handle than that of a PSRU. The direct-drive big block will weigh about the same as a small block with a PSRU. And the cost will be much lower. Gary Casey