JR>> I don't think that would be such a problem. Remembering that 
 JR>> the lubrication  on a four stroke motor is achieved from 
 JR>> "under" the combustion chamber - not from within as with two 
 JR>> stroke motors.
 TO> True, but wouldn't the steam tend to strip lubricants, and end 
 TO> up in the crankcase as well? I wonder. Maybe one of these days 
 TO> I will try to retrofit an engine for this purpose. (I certainly 
 TO> have plenty of old motors sitting around.) Take care.
 JR> Well..... Maybe. I think by changing the oil more often you 
 JR> could get around it. Perhaps like car engines, if you reached a 
 JR> reasonable operation temperature the water would be "boiled 
 JR> out" of the oil system. 
There's a mailing list on the internet that I've been browsing lately,  
something like "diy-efi" where people are talking about doing all *sorts* of 
modifications to engines to get more performance out of them.
One interesting thread that's showed up in there lately is the deliberate 
injection of water into the combustion process.  It seems that when you 
really push an engine,  things tend to run a great deal hotter,  and the 
injection of water (plus usually some ethanol or methanol in the mix) tends 
to cool things off nicely.
I don't recall seeing any adverse effects in terms of lubrication mentioned 
anywhere in there,  though of course all of the factors involved need to be 
kept under pretty tight control.
 JR> It is also interesting to note that Strath Steam make a single 
 JR> cylinder horizontal mill type engine. It has a 3" bore and a 4" 
 JR> stroke. It seems this engine is rated as 5 horse power. Perhaps 
 JR> not a great output but obviously enough to run a generator.
 JR> I must see if I can get permission to post the details here.
I will look forward to hearing more if you do...
--- 
---------------