pat Farrell balancing a Stanley steam car engine

Pat Farrell explaining how he balanced his 30 HP Stanley steam car engine. 
reprinted from SACA  FORUM.
Re: Balancing an old steam engine 
I added additional counterweights to our 30 HP Stanley engines' crankshafts. Before the added weights, the Stanley engines started bouncing at about 47 M.P.H. Just minutes ago, I just blew down our 1911 Stanley model 85 7 passenger 30 HP touring after a 25 mile demonstration ride. I was giving some of my classmates (class of 1963) a thrilling ride at 70 MPH and there wasn't a bit of bounce anywhere coming from the engine. Smooth as silk! The Stanley still had more throttle left to use. The 30 HP Stanley car is unbelievable! The added counter weights made it just that much better.

 The counterweights that I added to our 30 HP Stanley engine were almost the same size as the counterweights that the engine throws already had on it. I do not know their exact weight. The were crafted by REMPCO in Cadillac, Michigan by Gilbert "Red" Hall. Phone number 1-800-736-0108 If one has a 30 HP Stanley and he is not using these counterweights as of yet, then they have not experienced the true smoother higher speed potential of their Stanley. Our model 85 is geared 50 to 60. Almost one to one. The tires are 36" in over all diameter. At 70 MPH, the Stanley engine is smoothly just loafing along.
Our 1911 Stanley model 85 7 passenger, 30 HP is old technology that they already had by 1911 and about 50 years of research in it to make it the most advanced form of transportation of its time. By updating in the proper areas, like engine balancing, modern metals, better brake lining, safety glass, better tires, so on and so on, we presently have one of the most advance forms of steam transportation in this modern era. Our model 85 has never disappointed me in its performance or reliability. I drive with modern traffic. Its handling is on par with many modern vehicles. My only short comings are that about every 50 miles I have to look for water, and I have to be cautious with its two wheel brakes. 
My pride is that this Stanley is that it is all scratch built with scrounged up parts by me. I tried to make it historically accurate too. 
People who scratch build their modern steam cars are unfortunate in that they often are trying to re invent the wheel again by using previous failed inventions. If the modern steam car builders would comb the back issues of our Steam Car Bulletins, they could learn a lot from the failed past ideas used with steam cars. Oh yes. I have had a lot or reworked parts through the years too. Perfection eventually arrives. 

Image above is a conversion done in England by Basil Craske similar to Pats idea.