Russell's Bourke 30 Explained In Simple Terms

Care of Hot Rod Magazine, 1954. 

Excerpted from the authentic original Bourke Engine Documentary, pages 111 thru 114, sold by Bourke-Engine.Com

This is an era of new engines. We are quite sure this is true for we read all about the revolutionary new engine designs in advertisements everywhere and listen intently as radio and TV personalities explain the remarkable engineering advancements contained in our present day automobile engines. Much has been accomplished in the past few years by beefing up the lower ends, converting to overhead valves, shortening the stroke to reduce piston speed and converting to complex four-throat carburetors.

The basic design, however, has been unchanged for over 50 years. Even longer than that if we care to go way back to the late 1800’s or early 1900’s when our successful racing engines of today were first put on paper. Designers and engineers of that period knew how to lay out an efficient engine comparable with our best of today, but alas, they were not blessed with the metallurgical advancements used freely in our present day engine laboratories. Their designs were forced to remain on the drawing board until metals were produced that could withstand the tremendous stresses and strains developed in high output four-stroke engines.

Perhaps we are now ready for the Bourke engine, or better yet, now that we have hopped up every Detroit engine to the point of self-destruction, the Bourke engine is now ready for us. It may not be the last word in design, for all designs will forever be improved upon, but at least it is a step in the right direction.

Russell Bourke, of Portland, Oregon, sole inventor and designer of this new engine, has long sought an answer to the wasted energies and to the reduction of stresses and strains in the conventional engine. It all began back in 1918 when Bourke was teaching engine theory and maintenance in the Air Service School at Kelly Field, Texas. Endless discussions with other instructors and students soon convinced Bourke that much was left to be desired in the internal combustion engine using the Otto cycle. Heavy, inefficient and employing too many precision parts, they would one day become as extinct as the stream-powered car.

For fourteen years Russell studied the problems and in 1932 came up with a new engine and his first working model. This first engine was basically successful but there was room for many refinements. In 1938 Bourke built a four cylinder radial to be tested for outboard marine use. This engine literally put itself back on the shelf. It had too much torque for existing drives. A less powerful two cylinder opposed unit was then built and it proved successful after 2000 hours of testing in a boat.

Check that "foxy" look as Bourke muses, "Look what I have here!" Engine can be expanded in multiples of two cylinder units to equal larger displacements, i.e., 2-4-6-8 cylinders and so on.

All the lost energies present in the four-stroke engine have been put to work. Like a Judo expert that makes use of his adversary’s strength and momentum. Bourke had made every lost motion in the engine perform a needed operation.

The engine and its functions are simplicity exemplified, yet the engineering and development involved are by no means simple. It is of the opposed cylinder, two-stroke type. Russell calls it a "mono-stroke engine". Indeed it is by it's construction and operation. Co-operative pistons are connected to one rigid connecting rod that shuttles through an oil filled, crankcase sealed off from the cylinders hence, no oil changes needed.. There is no blow by introduced into the crankcase to pollute the oil. There are only two moving parts in the engine: 1-The piston-connecting-rod- yoke assembly; 2-The crankshaft. All other parts usually found in the conventional engine have been discarded.

There is no flywheel as the crankshaft is dynamically balanced for all speeds and is not connected solidly with the piston rod assembly. Operated through a streamlined, high speed version of the “Scotch-Yoke,” all kinetic and inertial forces generated by the piston rod assembly are used directly for charging and compression.
The forces delivered to the crankshaft are then one-directional and permit a greater power output with almost instantaneous acceleration under load.

Before we attempt to follow the pistons through a complete crank revolution, let us take a close look at the parts involved.

THE CRANKSHAFT

PISTON-ROD-YOKE ASSEMBLY

The piston-rod assembly is made up of two machined plates that form the yoke, two rod extensions, two pistons with pins that fix them into permanent position (they do not swivel or turn on the piston as in conventional engines), and two rings on each piston. The two rod extensions are guided through pressure sealed bushings in the cylinder base of the crankcase.  

The piston-rod-yoke assembly is one of the two moving parts of the Bourke engine. The three-in-one bearing on the crankpin, above, slides up and down in the machined yoke. The slot in the side of the piston allows the new air/fuel charge to begin its escape into the transfer jacket, thus allowing a smoother flow, without pulsation.

(Continued on page 2)