How Cummins Designed a 14.3L Flat-Four With Eight Pistons, No Valves and

The 14.3-liter power plant is diesel-fueled and uses two-cycle operation rather than the more traditional four-cycle. As such, it must have air forced into the combustion chamber to complete a power stroke. That’s where the roots-style “supercharger” comes into play, running on a set of gears and feeding the engine with oxygen. It’s similar to old Detroit Diesels, though the layout isn’t inline or in a “V”—the cylinders are opposed.

At 0:28 for operation

They couldn’t possibly have gotten that idea for an opposed piston engine from Fairbanks Morse.

1 Like

I’m not really pleased to use TDC and BDC for this configuration. Can we call them Mid Dead Centre and Distal Dead Center?

But then how to talk about crank position in opposed piston toroidal engines?

Who got it from Junkers who probably got the idea from Doxford.

1 Like
1 Like

From what I have read the Abrams tank has a large heat signature because of the gas turbine. Would this Cummins engine be being developed in order to lessen this vulnerability?

That was my first thought too. I don’t know about the power distribution between the two banks of pistons in this but the FBM as was explained to me was 80% from the lower and 20% from the overhead.

But this sure looks to be the same animal.

Both Cummins and Fairbanks Morse used the same partner for the design; Achates Power

From the article:

Achates Power began modernizing opposed-piston engines in 2004, inspired by the record-setting Junkers Jumo 205 diesel aircraft engine.

Wikipedia has the same info:

Not too far off.

Since the lower leads by 12 degrees it produces about 70 percent, the upper crank produces around 30 percent. At least it does until you slip a vertical drive then all bets are off.

I spent a very long time tending those beasts on diesel subs.

1 Like

If you were on Diesel Subs, I would imagine you did.

Question for you. You probably saw the movie “Operation Petticoat” and noticed the problem engine they had. What would have been the problem with it ? (or was that just something staged to build intrigue ?

One of the best engineers I had was diesel sub guy with EMD’s (Not detroits in earlier post) as my mains… Could have used him even more when I was working on a tug with a Fairbanks direct reversible.

It’s been a long long time since I saw that movie. The only thing I remember about it is they had an old double acting steam pump in the engine room … obviously a prop for mechanical effect. The boat had Cleveland engines, 16-278s and what I recall most about them is they were a hoot to start when cold because you could count the cylinders firing and follow the action around the engine until it warmed up a bit. That and changing heads! The other 90 percent of my time was FMs which I really liked a lot.

Both FM and Clevelands smoked like mad when starting. We used to play with the overboard exhaust valves (hydraulic actuated) when starting alongside the dock. We would keep it closed until the engine started to spool up then open it to shoot a huge smoke ring across to the next pier.

Never saw a direct reversing FM until sailing with Alaska Marine Highway on the Tustumena before they changed it over to EMDs.

we had a few of these in OZ back in the day

1 Like

I didn’t realize they were other than FBM’s. Seems that was when they were acting up…on start up and when cold.

As for that steam pump…was that the scene the ranking nurse fixed it with one of her girdles since the Chief didn’t have a replacement spring for the broken one.
(the Chief didn’t think it was “proper” to have a woman’s “unmentionable” stretching back and forth…and the nurse argued that as long as it worked…
never underestimate the resourcefulness of women with their “women’s things”. :grin: )

Why do you think McGyver always has a girl with him? Two words: Tactical Hairclip.

1 Like

LOL :laughing:

Let’s not forget the Vincent 3 cylinder OP used on air drop lifeboats in WW2.

1 Like