A Unique Twin IC Engine

[GreenTwin]

I am still watching and studying this video, but some very interesting concepts for sure.
Would make an interesting model engine I think.

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[GreenTwin]

In this video at 7:42, sounds very much like the old John Deere Model H that I had.

 

[GreenTwin]

Somewhat similar to a Soule Speedy Twin steam engine, although the Speedy Twin was a very successful and robust design, and was in production for many years.

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[JimSvarv]

Thanks for sharing.
That valve train is pretty neat for sure.
Looks like he's turning the engine the wrong way when demonstrating it, at least if the lower valve is intake.

With atmospheric intakes you could also drive two cylinders with one push/pull rod.

 

[GreenTwin]

I am still trying to understand that valvegear, and not sure I have it figured out exactly.
The piston tripping the ignition contacts is pretty clever; not sure if I have ever seen that.

He mentions that the hole in the top of the piston (see 2:05) is for oil passing through for lubrication, but that can't be correct.
The indent in the top of the piston is for turning it, and it would not penetrate the top of the piston, if I am understanding him correctly.

The tube down the side of the rod is clever, but it seems like the tube would be prone to breaking from vibration/force side-to-side on the rod.

The leaded crankshaft is not a particularly good design in my opinion, although they do have some very hard babbit material that could work ok.
Babbitt comes in different grades/hardnesses.

At 6:30 in the video, perhaps someone can explain in layman's terms what I am seeing as far as the actuation of the valves.
I see them moving, but not sure I understand the pull-pull rod arrangement.
His explanation is a bit lacking in my opinion.
I am not sure if I have seen a twin rocker arm like that.
Normally the old engines had the intake valve drawn open atmospherically, ie: not actuated by a pushrod or rocker.

The engine has rollers operating on the cams.
I guess I need to think about how 1/2 of this engine works, and then understand how the two sides work together.

There is a reason I like single engines of all types; they are generally far simpler to understand, design, and build.
All of my motorcycles are single-cylinder, and that is the only motorcycle configuration I would ever ride.

And what are the flyballs doing exactly ? other than regulating something.

Seems like a starting handle boss could be incorporated into the end of the shaft that extends beyond the pulley.
The old John Deere tractors used the flywheel to start.

Edit:
Fun note about old John Deere tractors.
There is a punch mark on the flywheel of old John Deere tractors that is used to time it.
The factory timing mark that is cast into the flywheel requires you to bend over to align it, so the guys in the factory came up with a leather strap that they used to add the punch mark, so they could set the timing while standing upright.
My dad restored 12 John Deere old tractors, and had one at a big show up north.
The show folks brought "the John Deere expert" over to talk to my dad, and they said "this guy knows everything there is to know about old John Deere tractors".
My dad said "I know something he doesn't know".
They scoffed at my dad's suggestion of such a thing, and brought the guy around.
My dad said "You see that punch mark on the flywheel; that is how they timed the engine".
The guys said "That is absurd, that is just a stray punch mark, and has absolutely no meaning".
My dad said "It allows them to time the engine standing upright; go check every John Deere at this show (there where a large number of old John Deeres at the show)".
The guy went running around all over the show, and sure enough, he discovered that every one had that same punch mark in the same location.
He was totally flabergasted.
My dad said "Well you learned something new today about John Deere tractors today".

If you go to an old engine show, look at the old John Deere flywheels.
When the cast timing mark is horizontal, there will be a punch mark straight up, basically aligned with a bolt that is on a boss.

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[Jasonb]

Pat have a look at the Ford Quod thread where I explain how the ignition worked that also has a pin on the piston to trip the ignitor.

The hole in the top of the piston is the "TOP" as it is in position. So not the crown of the piston but the hole with the shallow milled recess on the top side. This would line up with the drip feed oiler and catch the oiler as the piston passes. Common on a lot of hit and miss engines to at least have this hole, the tube to feed the big end is not so common but I have seen it before

It is not Pull-Pull, it is Push- Pull. Quite simple and again could be compared to the Ford although that works the exhaust valves on two cylinders. It is probably best thought of like a steam engine with slide valve. The valve rod moves the slide valve either side of ctr and that is how the pushrod on this engine moves the rocker either side of vertical. So when it goes to 5 & 11 o'clock from vertical the side rod is pushed and the inlet is actuated and when it goes to 1 and 7 o'clock the rod is pushed the exhaust is actuated.

The bell cranks on the rods allow the cam to push the rod one way and pull it the other when the cam only has lobes that push the bellcrank So that may be where you got push-push

I suspect the lead was due to them not being able to machine an accurate rectangular pocket in the flywheel to fit the crankshaft so took up any inaccuracies. It would also have allowed the setscrews to be used to adjust the balance and then the lead would "lock it in position

You could always find a bit of rope on the farm to start it even if the handle had been mislaid

 

[Jasonb]

looks like the governor is linked back towards the head as I can't see anything else that actuates the smaller rod at the side of the engine. Certainly has a bell crank that converts the sideways movement of the weights to movement along the length of the engine. Sounds more like it is throttle governed than hit and miss so the rod mostlikely works a butterfly valve in the intake hence it goe sto the bottom of the head where the inlet is.

 

[Jasonb]

Upper bellcranks work cyl No1 so as the can hits green1 it will pull the top rod, as the cam hits pink 1 it will push the top rod. Same for the bottom rod 2. bellcranks pivot on the slotted pins which screw into the backplate

 

[Peter Twissell]

So are the ignition points inside the cylinders?

 

[GreenTwin]

So are the ignition points inside the cylinders?

Yes, typical make-and-break points inside the cylinder, as was commonly used before spark plugs, but with a twist that I have not seen, which is the points are opened by the rod on the top of the piston, so no external actuation of the points.
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[Peter Twissell]

I am aware that some engines discharge (and time) the high tension spark to the piston crown. This looks like low tension points in the cylinder.

 

[Jasonb]

They are not actually points in the way you would get on a car. There is a grounded contact and a live one.

As the piston comes up towards TDC it pushes the two contacts together to complete the circuit then as they spring open again the electrical energy wants to keep flowing and jumps between the two in the form of a spark which is what fires the engine. There is no separate spark plug. Ignitors are generally low tension.

More usually the contacts are still within the cylinder but they are actuated by an external trip, often fixed to the exhaust push rod