This is very unusual, to see a British Commer at work in the US. But it was during the great import boom, so I suppose some trucks made the trip across the pond too. These were referred to as “Commer Knockers” due to the sound the gear train driving to the blower made when it aged. The engine is extremely unusual, and it’s probably best if you just watch the video below that explains it better than I can in words.
Three horizontal cylinders with twin opposed pistons working rocker shafts and connecting rods to turn the crankshaft below it. Opposed cylinder diesels are not really that unusual; Fairbanks Morse was famous for theirs that powered subs, ships and locomotives. They still build them. But they have crankshafts on both ends.
Commer didn’t come up with this on their own. This design has a complicated history. Here’s a patent from 1934 by Ransom E. Olds. But he didn’t really invent it either.
Its origins go back to the illustrious Swiss firm of Sulzer, which developed the ZG9 engine prior to WW1. Apparently they licensed it to a Hill Diesel Engine Co. in Lansing, MI for marine use. In 1924, R.E. Olds bought Hill, and decided to…ah…take out a patent on it for a truck diesel engine, as diesels were seen as the next new thing for trucks, and of course his firm was REO, a builder of trucks. There were some differences though: the Sulzer used a large single piston (upper left “Kolben Kompressor” to scavenge the two cycle engine. Olds used an external blower, apparently not shown on his patent drawing.
The Hill engine was used in stationary applications, but the Olds design never made it into trucks.
But Commer (Rootes) was also inspired by the Sulzer, and its engine was used in large numbers of their trucks in the 50s and 60s. Here’s one starting up.
Thanks Paul, I have to say that I definitely learned something new today!
An Aussie knocker in the vid there. I remember the sound of these clattering about the neighbourhood and stinking it up with oily pongs, though my unreliable recollection has them generally only on trucks smaller than things like car-carriers.
I do like the faint-praise old saying about column gearshifts, which was that they are a splendidly complicated way of doing a very straightforward job, and I must say that’s how this set-up always strikes me.
That said, a glance online suggests an output of 105 (real)bhp from 200CI, which wouldn’t be shabby in a ’50’s petrol six of such size, let alone a more fuel miserly diesel, so it clearly did work. Same design also kept Junkers diesel planes in the air in earlier – if many times larger – forms too.
Via a brief and poorly-lit CCRabbbitHole marked “Look here!”, I found that the same essential design was being developed by a company called EcoMotors in Michigan in 2008, albeit with modern tech such as electric turbo, agnostic fuel needs and declutcable cylinder sets mid-crank. Seems Bill Gates and others were seed capitalists for it, and it was all rather set for large production in US/China, but the hole ends abrubtly in 2016. Can’t help wondering if emissions hurdles could not be overcome, the dead-end point of a number of attempts to revive two-strokerism.
Sounding very much like a Wartburg petrol engine . Does any body remember the “Screaming Jimmy” 2 stroke buses?. Still running in Vancouver. BC in 98.
Why would wax ny body buy these rather than the hundreds of domestic trucks ?.
Perhaps it was their very compact nature; even by British standards those old Commer/Karrier cabs were small so would maximise load space in the available length. Also low enough that the vehicle on the top deck can overhange the cab as shown. Some lightweight versions were built right up to 1978.
Leicester City Council were running the smaller Cub version up untill the late 70s.
In the early 1980s (’81-5) I used to pass a council depot on the way to work and they had plenty of ‘T’ reg. Karriers. Originally the cabs had two piece windscreens, but later ones were one piece, but still made of two flat sections with a fold in the middle!
KAT stands for Kenosha Auto Transport from Kenosha WI. At the time there where strict weight and length limits especially in Illinois and on the east coast and 500 less lbs or a cab 5 inches shorter could mean you could haul a extra car for more revenue in those days trucking was regulated and most Auto transports returned home empty. So it is very likely some of these trucks were used in the USA but I’ve never seen one .
Quite a surprise to see one of those in the US!
The noise was incredible in the unlined cabs, similar hp to a Bedford or Commer petrol six but they use far less fuel and you get that 2 stroke diesel racket when they are pulling hard.
Fascinating engine, cool compact truck. Thank you!
Would be interesting to see how this type of engine would compare power wise and weight wise with an equivalent displacement “normal” 2-stroke diesel.
Quite the monkey motion going on and would need a good lube system to minimize wear in all the rocker bearings. Should be less piston wear, doesn’t look like the connecting rods would run as much side load. Quite the interesting solution to get rid off the normal two crankshafts and tower shaft used with opposed piston engines. That’s always been the problem with the opposed piston engine for some applications, too tall. Sure nice to get rid of all the valve train though.
If you think about it, there are exactly as many bearings as in a conventional 6 cylinder 4 stroke engine, there should be less wear at both the crankshaft bearings,and the shaft is of course short and rigid compared to a straight-6. And the access is very good.
With modern materials and lubricants it would probably work very well, but nobody is going to develop a radical new Diesel design when the future of the ICE is so uncertain.
The distinctive whine these Commers made was due to the blower – we weren’t used to “supercharged” engines in the 50s – but I remember them as small/medium trucks rather than large ones.
This is beyond weird. The only explanation I have is a loaner from Rootes pending a possible branching into the US medium truck segment (this was before the Chrysler take over). I simply can’t believe any sane US operator would pay good money for an obscure truck using an unusual, and unfamiliar, engine configuration with no nation (or even State) wide dealership network to support it.
My father ran commer maxiloads in the 60s and 70s and was sorry when they ended production. There was a four cylinder version in development so the story goes but when the Roots group was taken over it was dropped. He said it would have been a great engine with plenty of power for the time.
Friends of mine at Boeing gave me the name of a firm that has the display Commer, spare parts and drawings. He bought a few of the old engines and rebuilt them for military application. They are extremely reliable… a plus for a stationary engine. He received a contract from the military for a few hundred a month, in the late 1980s. The U.S. firm who bought the remains of Commer filed a lawsuit to halt any ‘reproduction’ of Commer engine. My friend and I were going to have the engines built in China with CNG/LNG conversion. The US firm filed a lawsuit against my friends company. However, in Federal court the US firm was found in contempt of court. They ‘abandoned’ the technology by destroying the tooling. China would build the engine if we financed the project. This was during the mid-1990s. The small firm with ‘cutting edge’ technology (unless you have an angel with a billion bucks) has no chance of getting off the ground.
A project out of Boeing during the late 1970s was a rotary piston diesel. The engineers who developed the engine were given the patents with Boeing’s blessing. I visited their shop and watched the engine operating on a test stand. I was involved with a highly efficient heavy duty Class 8 truck. In a wind tunnel test our truck had Cd of .44, equiv to a model 944 Porsche. Road tests revealed a fuel savings of 40 percent against KW, Pete, Feighliner, Mack, etc. With this new rotary diesel, there would be 600 lb. weight saving against Cat 3208s, DD6V92s and various Cummins engines. The rotary diesel engine firm ran out of money trying to clean up the diesel exhaust. They never considered CNG. Years later the military gave a $26 million contract to a US firm for a rotary diesel engine!!! After they built a few I called the director of engineering to ask him if he could recall the name of the firm (of the ex-Boeing engineers) who were testing a rotary diesel…there was a silence, then he hung up!
Back to the Class 8 truck. My friend (a truck fleet operator/owner), plus a few of his friends and myself invested over $25 million trying to get it into production, from 1968 to 2008. The industry was afraid of it. The Federal Government had no intention of helping to increase fuel efficiency. Ye Old Dragon holds the world record at Bonneville for Heavy Hauler Class – 193 mph – beating teams from Freightliner and Kenworth – See it on the internet. The truck and chassis were built in 1980! There were 14 prototypes manufactured for testing.
I remember going up into Scotland with my dad,I guess in the late fifties or early sixties,very early In the morning. When we stopped at the side of the road for a break often we could hear the Vaux brewery Commer trucks coming from miles away in the still air of the morning. There was usually two together going from Sunderland up to Edinburgh or somewhere else in Scotland. Great memories for me in 2022. 😀😀👍