Originally Posted By: JTK
I wouldn't think you'd use a gear oil in that piston oiler. Gear oil doesn't do so well in 'combustion' application. I'd use a non detergent 30, 40, or 50wt if you could find it. If it was a fresh rebuilt job, a regular 15w-40. I love watching/listening to those old buggers run. I could spend days walking around old engine/equipment shows.
Joel
+1 on all that. I'd say non-detergent engine oil in a heavy single grade. There are a lot of antique engine forums where you could probably get a lot of advice.
Last weekend was the Burton Cotton Gin Museum festival in Burton, TX. There was a small array of similar "hit and miss" engines running on display- very cool. Of course the big draw was the fact that they fired up the gin itself process a bale of cotton, using the 16 ton, 125 HP @250RPM 1925 Bessemer shown in this video:
http://www.youtube.com/watch?v=MSEuJ4EVwHs
The video appears to be at no-load, its a lot more impressive when its actually turning the gin equipment. That engine has an oiler with an escapement drive that periodically pumps drips oil to all the external bearings. I'm not sure how its internally oiled (crank and rod bearings, cylinder walls), to be honest. The crankcase isn't tightly sealed, but it has cover panels over everything. It may actually be pressure-oiled for all I know. The fuel injection system would make Rube Goldberg smile, and there's a water pump and cooling tower outside to for cooling the engine. There's even combustion chamber water injection to regulate combustion temperature! When I was there, one cylinder was "hitting harder" than the other, so they had its water injector dialed up higher to balance the power and cylinder temperatures better.
And speaking of antique Fairbanks-Morse engines...here's one just a little bigger than your 3-horse...
http://www.youtube.com/watch?v=cY7hTT-Zk5M