Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Considering the H70 series engines serious design  (reverse cam timing, non-lubricated crank, rod & piston, etc,) issues & Not exactly built like a Swiss watch loose,.....Why would one expect the original Oem Cylinder groove & O-ring Dimensions + O-ring Shore A durometer to be anywhere Near functional sealing optimal ?? ....Fine tuning the original 2 groove cylinder O-ring ID/OD/Cross Section & Durometer selection will most likely correct the leaking issue.....2 x Bad = More Bad !!

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The new ones don't leak at all. Out of 5 H-75s and an H74.... Only one had a leaky cylinder. I sent it's new owner a set of for new cylinders.

As for the oiling, I open the crank case on the cam side and with a needle oiler hit all the friction bearing surfaces. Given that at shows I usually start and run it for 30-40 seconds at a time, multiple times all day, without the need to add more oil. I use a high quality synthetic clock oil along with an oil rich fuel mixture. When oiling I tilt the engine so I can lubricate each cam lobe and bearing along with a drop or two on the piston skirts. You can also place a few drops of oil on the lifters from the outside and it will wick inside to the cam lobes. My own thoughts on rotating the wrong direction..... I am glad it goes the wrong way. It is much easier to hand start clockwise and these are clearly not designed for severe duty service. If you want that, you can spend 7,000 or so to get one built or if you have the skills and equipment and hundreds of hours to spare... well...you know. I rather suspect that 5-10 years from now my H74 and H75 will both still run well. There is no slop in the bearings like we found in some of the hit and miss engines. While it may appear to have all these faults, it is still a lot of motor for the money and nowhere else is anyone duplicating anything close to them (for the money).