Monday, August 24, 2020

Tuesday Torque: Revisiting Old Threshers At Mt. Pleasant

 Midwest Old Settlers And Threshers is one of the shows that is cancelled this year, but they will be back. Here is a nicely restored Reid oilfield engine that I recorded in 2009.  Susan and I were fortunate to see engines operating in powerhouses when we lived in Eastern Kentucky. The Reid is pretty neat because it is a 2-stroke cycle engine.  Instead of the crankcase being used for intake and transfer to the combustion chamber, Reids use a charging cylinder running parallel to the power cylinder. They have their own sound.



Rick: Listen to the John Deere at 24 seconds as the operator cranks it. You can hear the atmosphrically operated intake valve snorting while the engine is at low RPM. Thanks for the question in Comments!

7 comments:

John in Philly said...

I've never seen or hear of a charging cylinder for a 2 cycle.

A shallow research dive into the internet left me with a little bit more knowledge.
One article mentioned "charging cylinder or Roots Blower."
I'm thinking that before mechanical blowers or exhaust driven turbochargers existed, a sort of piston supercharger had made its way onto engines.

David aka True Blue Sam said...

A piston supercharger is indeed what the charging cylinder is! They should have come up with that description a century ago and we would all be driving two strokes now!

Rick said...

These engines were used in the San Ardo oil fields in the southern reaches of Monterey County, California. They can be seen at the engine museum at Paso Robles, CA.

I have not seen one in operation. What makes the ratcheting sound? Looking at the throws of each cylinder connected to the flywheel, could the timing be altered at all between the cylinders? (Do I know what I'm talking about? lol)

David aka True Blue Sam said...

That rattling, ratcheting sound is the intake valve, because it is atmospherically operated. It will tag the seat and lift repeatedly during the intake. On small engines like 1 1/2 HP John Deere Es it is more of a Snort! I will see if I can find an example and add to the post. Thanks for commenting! PS: You could add a ring to the flywheel with a crank pin, and have an adjustment mechanism so the ring could be advanced and retarded while running. Some model maker has probably worked on an idea like that.There are some great possibilities for making a charging system that is adjustable on the fly.

Rick said...

David, I desire some clarification. What do you mean it will 'tag' the seat? And I assume where you mention seat you mean the intake valve seat. Yet isn't this a sliding valve? Does the intake open only once per cycle?
Thanks.

David aka True Blue Sam said...
This comment has been removed by the author.
David aka True Blue Sam said...

The valve lets some air in, the pressure in the cylinder is raised slightly by the incoming air, and the valve spring (Poppet Valve) makes the valve close. If the piston is still on the intake stroke, the valve will open and close again repeatedly, making the snort or rattle noise.