Grumman Cheetah and Tiger IO360

This is a long running topic for Grumman owners. Everyone wants one. Or, so it seems. I hear a lot of discussion about putting an angle valve 200hp IO360-C1C into a Grumman

It's been done, of course, but it's a lot of work. Fletcher Aviation put together a Tiger with an IO360 and a 3-bladed prop. They used a stock Cheetah cowling with an inlet enlarged to 3 or 4 times it's normal size. The air-box on this prototype was so large it would have to be removed to change the oil!

When they flew it, it was only as fast as a good Tiger. Certainly not worth the time and money to make the conversion worth while. They recently bought Peter Otten's STC for his 200hp IO360 into a Cheetah. The thing about this STC is, you need to start with a Cheetah and convert the spar to a Tiger spar and then install the engine. Like the Fletcher version, this one requires a special air-box too; the difference is, this air-box is a lot smaller and uses a stock Cheetah nose bowl. BOTH conversions require the following mods just to get the engine into the plane

1. The engine mount needs to be modified to get the IO360-C1C to fit
2. All new baffles need to be made.
3. A new air-box needs to be made
4. All of the controls need to be relocated.

Fletcher sold the Otten STC to Scott Jernigan. He and Bob Stewart were going to be partners and make a fortune on the 200 hp STC. Well, here it is, several years later and what they found was that the drawings in the STC didn't fit the parts they needed to make. They ended up making a lot of new drawings and still no flying 200 hp Grumman.

Certainly not insurmountable obsticles. But, why go through all of that? For what?

Tigers: There is an IO360, albeit, a 180hp parallel valve IO360, that will bolt right into a Tiger without any significant modifications. You reuse your stock engine mount, stock baffles, stock air-box, and, with the exception of putting a Prop control in place of the carb heat and changing the primer to an alternate air source, the controls all fit. And, yes, it has a constant speed prop. This IO360 will put out over 200hp with porting and polishing. It's also lighter than an angle valve 200hp IO360. In fact, with a light weight starter, the weight difference between the stock O360 and a parallel valve IO360 is negligible. Note: I have been comparing the size and location of the propeller controller (governor) for a rear mounted controller and the location of the Tiger air box. The carb heat air inlet (on the air box) may or may not be in the way of a rear mounted prop controller. The conversion using an updraft fuel injection throttle body (like that proposed for a Cheetah) may permit the rear controller to be used. Otherwise, a forward mounted controller coould be used.

Cheetahs: There is also a 180hp parallel valve IO360, that will bolt right into a Cheetah without any significant modifications. This conversion also uses the stock engine mount, air-box, and controls (with the changes as noted above). As for the baffles, the IO360 is wider than the O320 so some baffle stretching will have to be done.

Interested? I'll make you a deal.
. . . The first Tiger and Cheetah conversion will be done for the cost of the hardware only. All labor, certification, and paperwork will be done for FREE.