Conversion of 4 Cycle Utility Engine to Steam

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DavidA:
I'm following this build with great interest. But I am having a bit of a problem with the basic concept. I am not a steam man by nature, even if I am building a steam loco. But I have spent about half of my working life as a mechanic on internal combustion engines.

My problem is what I can't envisage how you will start a single cylinder, single action (steam only on one side of the piston) if the engine is in the bottom-dead-centre position. Or ,say, half way up on the exhaust stroke.

Do you have to initially turn it by hand ?

I can easily see how a twin will start. Or a single cylinder double action. But not a single.

My apologies for appearing so thick.

Dave.

vtsteam:
Hey DavidA,

I appreciate your questions so fire away!

It's true you can' just start from a stand still with a steam single if it is in the wrong position. You would have to rotate it a maximum of 180 degrees. You can do so at any speed, as long as you get there.

Not so with an IC gas engine. It needs to be turned over a maximum of 540 degrees under ideal condiitons, and at a speed fast enough to induct the fuel and air in the right mix and strike a spark, assuming it has a magneto. If fuel is not right at the jet in the right mixture, it will need to be turned over until that occurs. Also the mixture will need to be correct for the conditions of temperature and pressure. Hence the need for a choke, automatic, or manual, or fuel injection, often accompanied by a computer and associated programming.

I'm going to have to go outside shortly and start my snowblower. I'm sure that the above process will be demonstrated a few times over! :bang: :lol:

vtsteam:
Actually I didn't completely answer your question. Which was, does it have to be started by hand? You can start it by hand using the pull starter, or a crank, or take advantage of the ring gear on the flywheel and add a starter motor. Just like an IC engine. You could also rig something up clever to make the engine stop at he correct position for re-starting directly by steam.

I think this question comes up a lot because so many steam vehicles, cars and locos, did not use a clutch or transmission -- things that became commonplace after the IC engine came into favor because of its greater difficulty in starting, and its poor low speed torque curve.

DavidA:
Thanks for that. It is reassuring to me in that wasn't barking up the wrong tree.

Dave.

vtsteam:
DavidF, new ideas and experiments are important. And I don't think anyone is laughing at different ideas. We all work on estimation and experience, but those can be altered by experiment if results show them to be incomplete.

I'm taking a pretty conservative path with this engine -- backwards almost -- with an eccentric and external valve gear. But when finished it will be a nice baseline to try a few ideas out on. And it will probably bring up problems to solve. Which is a good thing.

BTW, cast iron naturally has graphite in its makeup, and I plan to make a new CI head when the weather warms. Not that I expect the valve to run dry, but CI will run better than aluminum I believe.

I think antifreeze in the sump would be a problem because it would need to be drained fairly frequently and replaced as it got contaminated or diluted in a steam crankcase. It's expensive stuff, and environmentally problematic. Not saying it is impossible to maybe work some of the problems out. But it wouldn't be my first choice. Obviously auto water pumps work fine in that medium, so other mechanisms are feasible with it.

The old water and oil crankcase mix seems to depend on the oil separating readily from the water and floating on top, so the two can be drained separately if necessary. Easy to get rid of the excess water due to condensation with a bottom drain plug, while maintaining the lubricating oil in the sump.

The oils recommended for this are heavy weight and very specific -- not your usual automotive multigrade high detergent motor oil, which would quickly look like a milkshake emulsion if mixed with water in a crankcase.

So, I think the fact that antifreeze an graphite would combine with water, might be the actual problem, separation and layering seems to have an advantage.

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