Rat Motor

[Frank DeBartolo]

What's a rat motor?

Frank DeBartolo
BC125-D
N43684

[jgerard]

A rat motor is usually made from an 0-200 by installing c-85 pistons(higher compression) and a c-90 cam(more torque). You must always check clearances to keep from smacking a piston in to the spark plug or valves, and while everything is apart you want to balance all the parts to make it run real smooth. Some guys use this combo in experimental airplanes to get 115hp from an 0-200 at 2700rpm(some say it's 120hp - probably related to RPM and some light porting work). Even though you are using certified parts I don't think it is an FAA approved engine. I have flown in some aircraft with a "rat" motor in them and WOW! much better than you would think. You can swing a longer prop than the normal 69" used on most 0-200 installations. A perfect engine for your next clip-wing taylorcraft.

Jason
N43643