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Opposed Piston Engine?

Posted by Peter Brow 
Opposed Piston Engine?
July 16, 2018 01:18AM
Caveat emptor, but interesting from several angles:

Re: Opposed Piston Engine?
July 16, 2018 06:07AM
Here a lot about opposed piston engine [steamautomobile.com]
Re: Opposed Piston Engine?
July 16, 2018 09:32AM
That design has been around a long time. The only production version I know about was the Junkers Jumo aircraft diesel. Modern versions were developed by Eco motors (see below) as well. None have succeeded both because diesels have become seriously unpopular (thanks VW) and because there hasn't been a pressing need to design new IC engines. The emissions and economy issues have been solved with computer engine management. Modern materials, assembly and manufacturing have kept the costs reasonable. I can't imagine a large manufacturer retooling for a completely different IC engine design.

Lohring Miller

Re: Opposed Piston Engine?
July 16, 2018 10:30AM

I had my Chevy Cruze turbodiesel out on the highway Saturday night and pulled an average of 54 mpg at 70 mph...really didn't mind paying a 15 cent per gallon premium for diesel fuel. Of course, incremental improvements are still possible. It's highly improbable that radical new designs are going to challenge the long period of refinement that is built in to new engines.
Re: Opposed Piston Engine?
July 17, 2018 04:15AM
I agree Ken, radical new ICs seen unlikely to beat anything now on the road. Yes, long term gradual improvement is important. Steam cars got shut off around 1925; mostly only occasional radical nut fantasies, rather than gradual scientifically road-tested improvements, since then. Graeme Vagg, who I respected & often followed his advice [eg, solid-biofueled steam cars], but also publicly trashed and personally disliked, criticized the idea that "everybody wants to start at the top". I agreed. So then I discussed starting at the bottom, and got condemned for "sticking to old-fashioned outdated junk". Ignore advice, get trashed; follow advice, get trashed anyway. Wzup wit dat. Ah well, no bigster. Start at the bottom, listen to but don't get discouraged by critics, and work your way up. Same way the IC manufacturers did. Their gradual advances, well, hard to say how much that has actually accomplished in the past 40-50 years or so. Emissions are a tiny fraction of what they were in the 1960s, but what else? My 2016 RAM 1500 pickup truck, 4000-5000lb weight & 347cid/5.7L V8 with latest/standard fuel injection, VVT, 8-speed digital-control ZF-based auto-trans, etc, gets about the same 10mpg city/16mpg hwy max that a comparable weight/displacement/air-drag 1960s gas-engined pickup truck got. I do strongly suspect, however, that it beats 5000-lb 1960s/70s IC pickup truck fuel mileage by something like 5-10%. Then again, I bought an older-model-trans 6-speed new truck in 2015, which got totaled by a giant falling oak tree branch, long story, then went to the 2016 model, only 8-speed available, which cost several thousand dollars more, and have yet to see any discernable mpg improvement. Certainly no improvement to justify the extra cost of the "latest hi-tech developments". At least from my consumer-level first-hand perspective.

I could have gotten the FIAT V-6 diesel engine option, and could be racking up 30mpg on the highway. But that would have cost me $6000 extra out of pocket, and with the small number of miles I actually rack up per year, it is highly doubtful that fuel savings would have outweighed the extra up-front cost of the powerplant, over the realistic service life of the vehicle. Even the salesman who sold me this truck, noted that he had some customers who put big miles on their trucks, who benefitted from the higher-mpg diesel engine, but for my realistic elapsed miles, it didn't make sense. "The gas V8 makes more sense for you". He said, talking himself out of hundreds of bucks extra sales commission

Big car company boardroom corporate execs have their own govt-acceptable test documents, and a whole different perspective and frame of reference. Never mind that VW/Audi followed their rules, and produced mpg/performance figures which were officially accepted -- until it turned out that VW's test results were "cooked"/faked via vehicle-control-system software tweaks. Oh yeah, not too many years ago, at this forum, I remember noting technological problems with the MPG/performance/emissions issues of diesel engines, and being told that VW's results "proved" that VW's Experts knew more than I did. Fast forward a few years, and VW's Diesel Experts are fired/fined/jailed -- and VW is paying big fines.

[digression deleted]

Anyway, Ken, I am happy to hear that your diesel car is delivering 54 mpg in highway cruise. Right on man! But I used to hear the same highway-mpg claims, or better, for Otto-engined Japanese economy cars in the 1970s. Usually from people scoffing at the peak 27 mpg I got from my old aircooled VW Bug. Not questioning your results, just the propulsion system efficiency improvement over the Old Days. Today's cars have vastly lower air drag than the cars of yore. Antique car bodies got an aerodynamic coefficient of drag {Cd} of about 0.78; later "envelope bodies", even the boxy/crummy ones, came in around 0.50 -0.45; modern car bodies average around 0.35; best aerodynamics, like GM's controversial "suppressed-technology" [?] EV-1, come in somewhat below 0.20. A very few of the very best around 0.15. Highway fuel mpg is almost entirely a function of aerodynamic Cd.

Cars with much better mpg might get that via much lower air drag, rather than via big increases in powerplant efficiency.

At present, "fracking" and other improved automotive fuel production technologies have reduced petroleum-based fuel prices to historic lows, when adjusted for inflation. Today's situation is very different from that of the "Energy Crisis" 1970s, when it was generally believed that oil supplies were running out and oil prices would inevitably continue to increase. The SACA Storeroom carries -- or at least used to carry -- a re-printed 1918 article by Waldemar Kaempfert, in which it was confidently predicted that current [1918] oil reserves would soon be exhausted, and the steam car's ability to run on agriculture-based alcohol fuels would give the steam car a decided advantage. Many people tend to read such scare stories, and to continue to base their thinking on them for many decades after such dire predictions become obsolete.

Meanwhile, by my calculations, a wood-chip fired steam car could run on renewable/carbon-neutral solid biofuel for the equivalent of running an IC car on gasoline at 50 cents a gallon. That is based on the current cost of wood chips purchased in bulk bags from US retail hardware/home-goods chain stores like Home Depot and Lowe's. Wood chips take virtually no energy to produce from raw waste wood -- throw discard branches and waste wood into a chipper machine -- and in a steam car nearly 100% of their heat content is input into the powerplant, versus less than 50% of the wood's potential energy put into a IC powerplant via a "gasogen" system, according to John Ware Lincoln's book on the subject. The gasogen IC car blows over 50% of the wood's energy into the atmosphere as waste heat from cooking the gas out of the wood, and cooling the gas to feed it to the IC engine, whereas the solid-fueled steam car puts nearly 100% of the wood heat into steam. Even if the steam engine uses twice the BTU's for a given level of performance, it is still exactly as efficient as the gasogene IC system, and with vastly simpler and less expensive equipment. Also, wood gas requires more than twice the IC engine displacement for the same performance, relative to gasoline fuel. Which is fine if you want a tiny economy car with a giant V8 engine to compensate for the low-energy-density wood-gas fuel. Apologies to fans of performance-model variants of the 1970s AMC Pacer/Gremlin, but that's not looking like a future market winner to me.

I am not rejecting Jeremy's corn-burner approach, or the wood-pellet or other alternatives which have been proposed. I just haven't done the research & math on them yet. As Jim Crank used to say, "opinion subject to instant change".


Edited 2 time(s). Last edit at 07/17/2018 06:34PM by Peter Brow.
Re: Opposed Piston Engine?
July 17, 2018 04:53AM
OK, heh, I just can't resist a bit of Bugs Bunny "Gee, ain't I a stinker?" jerkiness

Opposed pistons? OK, nice to ditch the hassle of cylinder heads, valves, etc..

But it's hard to beat the simplicity, designability, build-ability, compactness, and gosh darn it, let's face facts, long-standing road-proven actual driveability and road-worthiness, of the dumb old Stanley double-acting inline-twin flat-D-slide-valve steam engine, with its "holy guacamole Batman" incredibly insanely obscenely disgustingly gigantically long curvey goose-neck counter-flow steam passages between flat D-slide valves and double-acting cylinders.

Yes, yes, yes. It is theoretically/thermodynamically horrible. And it is awful. And it stinks And it is rotten. And primitive, and inefficient, and outdated, and on and on and on and on and on and on and so forth...

Let's get up on that soapbox bully pulpit and bitch and whine and scream and declaim about the unthinkably unforgivable horribleness of this "worst idea ever conceived by any human, ever". Join with me now; so evil, so awful, we stand united against the primitive stupidity of it!

But it has delivered millions of miles of fun driving to hundreds of thousands of steam car drivers all over the world. I'm still waiting for "more efficient" steam engine designs to do that.

Oh, snap.

Snappy snip-snap, baby!

Gee, ain't I a stinker?,

Re: Opposed Piston Engine?
July 17, 2018 08:54AM
There are two main reasons cars didn't appear to get all that much more fuel efficient (until very recently) with technology improvements, emissions and safety. The engines have gotten more efficient, but at the same time we have added thousands of pounds of safety equipment and design, and caused a massive decrease in vehicle accident fatality. The fact that we haven't seen a decrease in economy is fairly impressive. Secondly, a lot of emissions improvements come at the cost of efficiency. Many ways of increasing efficiency also make the car burn dirtier and vis versa. This is especially noticeable with diesel emission control methods.

There are three main emission reduction methods with diesels. Urea injection adds weight, complexity, and consumables. Diesel particulate filters require after engine fuel injection to regenerate the filter, which consumes extra fuel. Diesel EGR reduces combustion temperatures, which reduces thermodynamic efficiency, and the recirculated exhaust gas can't be burned, which reduces the power/displacement ratio.

Currently, wood pellets are ~40% the cost per btu of gasoline, cheaper if bought by the ton. Also, wishful thinking, if a nuclear fusion powerplant ever becomes small enough to fit in a car (that doesn't use direct conversion of charged particles into electricity, but is a thermal design) then steam cars have an opportunity to make a second renaissance.

Perhaps a little off topic, but I still have a feeling that rotary steam engines haven't been given the attention they deserve, especially when scaled up and/or compared to a stanley engine. If mazda could sell wankel engines all the way until 2011, there's got to be some hope. All the rotary steam engines I've seen have many problems with the design that significantly contribute to leakage. The designers always seem to want to add weird complex moving parts (and valves! why would you add valves to a valveless engine design?), perhaps so they can say their design is "new". They also seem to want large diameter stubby motors, which is the opposite of what you want when the majority of the leakage is on the ends of the rotor. You would want small diameter long motors, to minimize the size of the rotor ends where you can't seal well. The vane tips aren't much different than a piston ring sealing wise. Also, having the ports on the sides of the casing is bad, as the incoming steam pushes the vanes down, unless you add strong friction increasing springs. (this was a big contributor to friction/sealing losses in a scientific study on a rotary steam motor) The ports should be on the ends of the case.

In a sense, the ideal design for a rotary steam engine would be very similar to a pneumatic die grinder. Also, a rotary engine will seriously benefit from the cube root law when scaling up. A standard (smaller) industrial air vane motor has some design problems that don't make it ideal for steam usage either. A more ideal design for a larger motor will have to be custom built, but since it's super simple, it's gonna be waaaay easier to machine than a piston engine.
Re: Opposed Piston Engine?
July 17, 2018 11:12AM

One could say you are opposed to opposed piston engines....LOL !!!
See what I did there?

Couldn’t resist posting that. Came up with that all by myself.
Ok...that’s all I have...sorry....

I will go now....

Re: Opposed Piston Engine?
July 17, 2018 11:33AM

I experimented with running pneumatic stuff on steam with mixed results. Some of them work great, at least until the plastic parts melt. I bought a pneumatic grease gun at Harbor Freight that pumps grease at 3,000 or so psi. I thought it would make a great steam powered feed pump. It did work, but suffered from the same temperature limitations. Actually....I might take that thing apart and see what it would take to “steamify” the air stuff and make the pump part more water friendly. Higher temp seals....replace plastic parts with metal...might be doable. It would be great to have a high pressure feed pump that can be turned on/off as needed, not constantly running and dragging on the engine or drawing electrical current. Just needs a flow of steam from the boiler to work, easily controlled by a manual or automated valve.


Here is the exploded view of all the parts and the parts list for the grease gun....if I’m not mistaken, it looks like an air powered, bash valve piston driving the pump! If I’m correct...I wonder how they make it self-starting? Interesting...

Edited 1 time(s). Last edit at 07/17/2018 11:51AM by Arch-Tone.

Re: Opposed Piston Engine?
July 17, 2018 02:54PM
For 100psi saturated steam you just need to change out the o-rings for viton. Funny enough, it seems that the cheaper equipment has less plastic. the fancy brand name solenoid air valves at work are chock full of plastic, but the chinese valves I was using for my engine were almost entirely metal. Same thing with the air cylinders. The harbor freight die grinder and air drill I've taken apart don't have any plastic in them. They have metal vanes and easily upgraded buna o-rings.

A steam powerplant could have its own water hydraulic system. Just tee off the outlet of the feed pump past the check valve into the boiler. You wouldn't have any pressure until the boiler warmed up. The feed pump is what's supplying the pressure. You should just get cold water if your feed pump keeps the boiler water level steady enough.

Your grease gun looks like it works more like a steam water pump. The valve is actuated to exhaust when the piston hits the bottom, then a spring returns it to the top, where the valve is pushed back to supply, and so on. Sort of like a bump valve I suppose.
Re: Opposed Piston Engine?
July 17, 2018 07:36PM

It gets complicated. A thousand pounds or so of extra weight for safety features, plus about the same city fuel mileage, that is impressive. For highway & combined fuel economy, weight is a much smaller factor and the air drag reduction is a much bigger one. I suspect that the newer IC engines generally do better than their 1960s counterparts at low load and part load, in city driving, and that the maximum/optimum-conditions efficiency has not increased by much, if at all.

But the truck thing is a head-scratcher. Weight hasn't increased, and air drag hasn't decreased by much, and the engine & transmission have all the latest bells and whistles that supposedly improve engine efficiency in typical driving conditions, but I'm getting the same minimum fuel mileage that I used to hear old-truck guys complain about, and the same maximum that they used to brag about. My city and highway results match what I remember seeing in newspaper and magazine road-test articles for same weight/air drag pickup trucks in the 1970s & 80s. A head-to-head test would probably show small improvements for the modern truck, maybe 1mpg better in city driving. But it is not noticeable to a typical driver. Also, the propulsion system costs more now. Even between 2015 and 2016, the cost of basically the identical truck went up by something like 1-2 thousand bucks, in this case probably because of the 8 speed trans replacing the 6 speed option. That was an expensive tree branch.

I'm still getting used to the dial control for the 8-speed transmission. The other day I backed out of a parking place, then twisted the shift dial all the way clockwise to "Drive". But the truck didn't shift from reverse into drive. Then I noticed that suddenly the air conditioning was going full blast. I had turned the AC dial instead of the transmission dial! That wouldn't have happened with the old-fashioned shift lever on the steering column, like the old 6-speed transmission had.

Thanks for the info on wood pellet cost. Interesting that even that relatively highly-processed solid biofuel is substantially less expensive per BTU than today's cheap gas. I plan to do a bit of research and see what would happen if it were taxed for road use, which might become an issue if solid-fueled cars started appearing on the road in significant numbers. Even if road-taxed at the same rate per btu as gasoline and diesel, I suspect that solid fuel would still be a bargain.

Rotary engines, now there's a big topic! I think that Wankels, and possibly other rotary designs, could be a contender if there were a durable coating which would both resist sliding wear and minimize heat absorption/release from its surface ("surface losses"winking smiley. Maybe like that laser plasma coating that Jay Leno used on the combustion chamber liner in Howard Hughes's Doble Roadster. That stuff stops metal surfaces from absorbing heat, but would it survive if it were sprayed onto the sliding surfaces of a piston, or on the walls of a cylinder? Probably OK for non-sliding steamed surfaces inside the steam engine, though. The next question is how much it costs. If it's something crazy, like 10 bucks per square inch, then maybe not. But I am keeping my eyes open for coatings like this.

Hi Jamison,

Badum-bump. LOL! Yes, I am, uh, opposed to opposed pistons. Well, at least to building them in my own workshop. I would be interested to see the details and results of somebody else building an opposed-piston steam engine, though. A few ideas for puns on the word "piston" come to mind, but I'm trying to keep the "sailor talk" under control. smiling smiley

Re: Opposed Piston Engine?
July 18, 2018 08:34AM
The process of pelletizing uses ~1-3% of the resulting energy of the pellets. Also, you can pelletize grass, which is cheaper and more land efficient, but the ash content is higher and the flue gasses have more sulfur in them which will corrode non stainless components much faster. (which is why using grass pellets will void the warranty for most pellet stoves)

Until very recently, stricter emissions standards have overridden increased mpg requirements. The past few years (and the addition of epa fleet mpg requirements, and plateauing of emissions reduction) have seen a refocus on mpg. This is why we are seeing things like smaller turbocharged engines, and engine control systems that shut down cylinders when cruising, only in the last few years. You also see technologies like HCCI and atkinson bieng developed. Car companies don't have to devote as much research into emissions and can refocus on economy.
Re: Opposed Piston Engine?
July 18, 2018 05:41PM

I suspect that producing wood chips uses even less of the energy in the fuel, because the wood is not cut as finely or run through an extruder. They just toss branches, etc in a chipper and it flies right out the other end, ready to bag. Also simpler and less expensive equipment needed to make wood chips. I will look into grass pellets. Somebody once mentioned an issue with chlorine compounds in grass combustion gases, maybe from city lawns irrigated with chlorinated water? I wonder how grass pellets would do with copper boiler tubes. Lots of steel-boilered steam electricity plants have burned bituminous coal, loaded with sulphur, with big stack scrubbers to eliminate "acid rain" by recycling the sulphur oxides into sulphuric acid. Selling the valuable acid made the scrubbers actually turn a profit.

A solid-fueled light steam power system could/should have some kind of cyclone chamber to separate the ash from the gas. That could be built into the burner itself, upstream from the boiler tubes, so that the tubes don't make an ash of themselves. Going "deep green" would also involve returning the ash to the land where the fuel was grown, to avoid soil mineral [micronutrient] depletion.

My 2016 truck engine has cylinder de-activation, basically one bank of cylinders in the V-8 shuts down at low engine load. A little "eco" light on the dash blinks on when the extra cylinders disengage. Without that light, I wouldn't be able to tell. Much of the time I'm driving on 4 cylinders. One of the engine tech pages I researched when truck shopping said that it is the same 4 cylinders that shut off, yet manufacturer tests showed no significant difference in wear between the cylinders that shut off and the ones that run full time. Impressive.

One of the Japanese manufacturers was looking into "Miller Cycle" operation, which is just a variable valve timing trick that gives the same cycle as the Atkinson, without the Atkinson engine's wacky crankcase mechanism. Basically the effective "intake stroke" is shorter than the power stroke, so the combustion products are expanded more than in a standard Otto cycle, squeaking a little extra power out of the gas. The company estimated 10-15% better fuel economy under some conditions. Gas engines are so inefficient at low loads that even "relatively" big improvements under those conditions don't amount to much.

Stanley made variable valve timing a standard feature in 1910. Glad to see that "the gas car boys" are starting to catch up. smiling smiley

Re: Opposed Piston Engine?
July 20, 2018 12:27PM
Hi Peter,
I love the opposing piston design in the German U-Boat!

Do you think that the opposing piston design is good for a Steam Engine? Please keep your response to reasonably amount of ~150,000 words grinning smiley

Kind regards,
Rick H.
Re: Opposed Piston Engine?
July 21, 2018 02:32AM
Hi Rick,

I think that an opposed-piston steam engine could be designed & built to run well and do serious work. It would have the advantage of balancing the reciprocating masses of the pistons, and eliminating the cylinder head. If the rest of the mechanism were set up for good balance, and if the valve ports were big enough, it could run under load at high rpms and therefore could be built smaller and lighter than conventional/traditional steam engines for a given horsepower output.

For acceptable steam economy, I suspect that it would need insulated piston crowns and a number of other tricks which have been tried, or at least proposed, to improve the efficiency of single-acting steam engines. Large valve ports, small clearance volume, and short/small-surface-area passages could be achieved with sleeve valve(s). There are several different types of sleeve valves to choose from.

I have no idea how its cost, performance, and efficiency would compare to a conventional steam engine. That would depend on many different design details. Ask 10 steam guys the best design for it, and you'd probably get 11 opinions.

One reason I personally do not currently plan to build an opposed-piston steam engine is the number of moving parts. A conventional double-acting steam engine gives 2 power strokes per crankshaft revolution with one cylinder & 3 moving parts (piston/rod, conrod, and crankshaft). To get 2 power strokes per revolution with an opposed-piston engine, you would need 2 crankshafts and 2 cylinders, each with 2 pistons and 2 conrods. So, 4 pistons, 4 conrods, and 2 cranks, for 10 moving parts to do the work of 3 in the traditional engine. Then consider that acceptably smooth running and good dynamic balance would probably require a design with more than 2 power strokes per crankshaft revolution.

Maybe low-cost off the shelf IC conrods and pistons could be used, to reduce the fabrication work. Perhaps just secure insulating caps, or some refractory coating, to the piston crowns. If suitable off the shelf IC-engine crankshafts could be found, that would also save on shop work. Designing & building a custom engine frame or block to incorporate all those parts would be a much more difficult job than a traditional frame-rod double-acting engine. Off the shelf cylinder liners might be possible if the piston stroke were very short.

There are also single-crankshaft opposed-piston engine designs. Those designs require some very unusual custom-built links & levers to connect the pistons to the crankshaft.

Some years ago, on this Forum, there was a fair amount of discussion about opposed-piston and rotary steam engines, including a lot of input from Jim Crank, who was very knowledgeable -- and opinionated -- about these engines. Over the years, he seems to have intensively researched every possible design for an improved steam engine. A search engine should turn up those threads. Lots of interesting information in those threads, including useful & thought-provoking info on more conventional engine designs.

There ya go, under 150,000 words. I think. smiling smiley

Re: Opposed Piston Engine?
July 21, 2018 03:10AM
Hi Rick,


I hope the link to this 2011 thread works, because wow. I went from snark to "traditional steam forever", then Jim Crank got revved up, great info and controversy all around. I've turned into an old soft shoe in the debate department. The steam world, and the world in general, has gone through a lot of trauma since 2011.

Re: Opposed Piston Engine?
July 21, 2018 05:41AM
Hi Peter,
I agree with your anaysissmiling smiley I guess what is important is stuff like hp/wt ratio, no of moving part and friction along with ballance.
Nice job!
I think the opposing piston belongs to the otto cycle...that's where it belongs.
Kind regards,
Re: Opposed Piston Engine?
July 21, 2018 05:33PM
Hi Ricky,

IC engine manufacturers, rightly or wrongly, seem to think that opposed piston designs are not even good for IC engines. As far as I know, no opposed-piston engines have been commercially produced for a long time, not even for high-performance use. My guess is that nowadays improved power to weight ratio, etc can be achieved with older, simpler, more traditional/conventional IC engine layouts, by different means, with less expense than going to opposed pistons. IC engine manufacturers prefer things like 4 valves per cylinder, computer controlled air & fuel, cylinder deactivation, variable valve timing, and more precise balancing, tuning, and manufacturing technology.

Very small differences in mechanical efficiency can be crucial for IC car engines, due to fuel economy regulations. Subaru now plan to discontinue their trademark horizontally-opposed 4 cylinder engine, in part because an inline-four has slightly less friction loss than a "flat four". Higher friction losses from all those extra large moving parts may be another reason why IC engine manufacturers avoid opposed-piston engines.

Re: Opposed Piston Engine?
July 22, 2018 11:01AM
Hi Peter,
I was working on the tablet and the Y is close to the H...hence the Ricky, meant to be Rick H.

Anyway, there is something to be said about the use of designs over time. Most all successful running steam cars use a proven engine like the Stanley or White, etc. I personally like the Stanley with the direct drive on the axle. Perhaps it could be made with independent suspension along with front and rear wheel drive. Even better would be to make HP and LP with a reheat in between. Just a thought.

I will always like the thought of the U-Boat opposing diesel engine design.

Kind regards,
Rick H.

Re: Opposed Piston Engine?
July 24, 2018 01:58AM
Hi Rick,

Oops, sorry man. Yep, Rick then space, then typo-Y, automatically spell-corrects to Ricky. Spell check and auto-correct are always messing with me too, owing to my addiction to humorous/regional misspellings and non-standard oddball words. I usually find a way to monkey-wrench it smiling smiley.

Neat ideas for independent suspension and separate hp/lp engines working as a compound. My worry is that poorly-balanced Stanley style engines might make for shakey running if mounted solidly on the vehicle/chassis frame. The "worst possible balance"/"roughest running possible" Stanley-style engine ironically gives butter-smooth, "feels like there's no engine at all" performance in a car, by virtue of the fact that it is mounted on a solid axle. The flexible/pivoting hanger strap at the front of the engine, and the wheels/brakes next to the outboard spring mounts acting as huge smooth-out flywheels, isolates the chassis and body from the engine, and gives the fabulous illusion of the smoothest engine in the universe. But bolt that same engine solidly to the chassis, and it might very well shake the teeth out of your head.

I love the Stanley style engine, but I admit -- and carefully design around -- its serious shortcomings.

Even de-coupling the engine from the axles/wheels, via a clutch, then running the engine, usually in an effort to improve warm-up, will shake a Stanley-engined car like a paint mixer. A few people have tried it over the years, with horrendous results. The Stanley-style engine needs the "massive flywheel action" of the wheels and brake drums/disks, and the pivot/flex front hanger strap, to give smooth running, whether on the road or with one/both rear wheels jacked up for stationary running. Actually not much different from the Old-Detroit approach of mounting shakey IC engines and bodies to the chassis or unibody via squooshy rubber blocks...

There has been, and IMO always will be, a lot of "learn the wrong lesson" and "select the wrong alternative design" surrounding these curiously complex engineering facts.

For HP engine at one end of car, and LP engine at other end, plus independent suspension front & rear, I would go for a pair of 90-degree V-2 double-acting engines. Ideally with crankshafts parallel to axles. These can be nearly or perfectly balanced, and therefore chassis-mounted w/o shake problems, but there are serious packaging problems. The extreme compactness of a Stanley style engine, as with many steam, EV, and IC car component design options, comes with a rather rigid set of tradeoffs/choices.

Re: Opposed Piston Engine?
July 24, 2018 02:49AM
Hi Rick,

OK, I'll bite. I do not remember the U-boat opposed-piston engine design to which you refer. Any links or images to post?


Edited 1 time(s). Last edit at 07/24/2018 02:49AM by Peter Brow.
Re: Opposed Piston Engine?
July 24, 2018 12:12PM
Hi Peter,
Thanks for the food-for-thought on the engine mounting. I'll incorporate isolation mounts on my Stanley Engine installation. Yes I'm planning on a Jaguar rear end on my Stanley H.

Hey buddy...out of time at lunch here. You are an excellent searcher (better than me), type in U-boat opposed piston engine, go to images and you'll see many.

Have a great day!

Kind regards,
Re: Opposed Piston Engine?
July 24, 2018 07:24PM
Found this on YouTube:


Re: Opposed Piston Engine?
July 24, 2018 09:46PM
Hi Rick,

The isolation mounts might just do the trick. Independent suspension has a number of advantages. I just did some searching for u-boat opposed piston engines; no luck yet [I will keep looking], but found loads of other opposed-piston engines. Definitely an ingenious and fascinating type of engine. The one I mentioned with one crankshaft and the funny links & levers was the Commer; actually I kinda like it. The Wikipedia page has an animation of it, which is fun to watch.

Hi Jamison,

Thanks for the link; that's a neat engine design, and great animated graphics!

Re: Opposed Piston Engine?
July 25, 2018 03:45AM
The Commer engine was quite popular in its day - a local milk tanker so fitted came past our house every morning in the 1970's making a very distinctive two stroke yowl.

Re: Opposed Piston Engine?
July 26, 2018 01:30AM
Interesting to consider that these unusual engines were not mere experiments or toys, but commercially and technologically successful machines which did a lot of useful work.
Re: Opposed Piston Engine?
July 26, 2018 12:00PM
Nice link Jamison,
I'd buy that F150 with this opposed piston design!

On an interesting note, I think that a opposing piston design would work well on lawn tractors. Again, I think the Diesel Cycle (Otto) or considered the compression ignition engine works well for this concept. So if you take two (2) gasoline engines and put them end-to-end to achieve the opposing piston design you get an increased compression ratio. In other words, take gasoline IC engine with 8->1 ratio; then double that (end-to-end concept) and you get a compression ignition, compression ratio for sure. Makes sense doesn't it?

OK, back to the lawn tractor, it is not regulated with these stupid tax laws and regulations pertaining to diesel. Rudolf Diesel demonstrated his diesel engine in Paris running on Peanut Oil. [en.wikipedia.org]
So I'm down with using my leftover cooking oils to mow my lawn. It's an oxygenated fuel so it's not as bad as the existing lawn mower engines. Furthermore, I'd make it a Hybrid and drive everything with electric motors and battery power. The idea is to run the diesel at one generating speed. Batteries would charge between mowing by PV panels...it goes on.

Sorry folks, this is a big divergence to Steam. Someday I'll work on this opposing piston development and after I get my Stanley H running and screaming passengers because it goes so fast cool smiley

Kind regards,
Re: Opposed Piston Engine?
July 27, 2018 03:02AM
The ultimate opposed piston engine was the Napier Deltic.


Edited 1 time(s). Last edit at 07/27/2018 03:02AM by Mike Clark.
Re: Opposed Piston Engine?
July 27, 2018 06:47AM
Rick.H Wrote:
> Nice link Jamison,
> I'd buy that F150 with this opposed piston
> design!
> Peter,
> On an interesting note, I think that a opposing
> piston design would work well on lawn tractors.
> Again, I think the Diesel Cycle (Otto) or
> considered the compression ignition engine works
> well for this concept. So if you take two (2)
> gasoline engines and put them end-to-end to
> achieve the opposing piston design you get an
> increased compression ratio. In other words, take
> gasoline IC engine with 8->1 ratio; then double
> that (end-to-end concept) and you get a
> compression ignition, compression ratio for sure.
> Makes sense doesn't it?
> OK, back to the lawn tractor, it is not regulated
> with these stupid tax laws and regulations
> pertaining to diesel. Rudolf Diesel demonstrated
> his diesel engine in Paris running on Peanut Oil.
> [en.wikipedia.org]
> So I'm down with using my leftover cooking oils to
> mow my lawn. It's an oxygenated fuel so it's not
> as bad as the existing lawn mower engines.
> Furthermore, I'd make it a Hybrid and drive
> everything with electric motors and battery power.
> The idea is to run the diesel at one generating
> speed. Batteries would charge between mowing by
> PV panels...it goes on.
> Sorry folks, this is a big divergence to Steam.
> Someday I'll work on this opposing piston
> development and after I get my Stanley H running
> and screaming passengers because it goes so fast
> cool smiley
> Kind regards,
> Rick

You can't increase the compression ratio by taking two gas engines and sticking them together. The stress will be the same. The piston and cranks will experience the same forces as if they had a static head.

I've given a casual thought or two to algae biodiesel. It's super easy to grow, or even better, just farm out of an existing lake. Dry it out in the sun and press out the oil. Even unmanaged ponds can produce far more oil per acre than any ground based plant. I thought about some day buying a few kiddie pools and growing algae. I also calculated how much it would cost for oil from black sunflower seeds, pressed from those big bags you can buy. If I remember right it was around $10 per gallon if you press it yourself for free.
Re: Opposed Piston Engine?
July 28, 2018 03:56AM
Bolting together 2 gas/Otto cycle engines and running them as an opposed-piston Diesel, is as problematic as converting a regular Otto engine to Diesel. Oldsmobile did this in the early 1980s and had huge problems. Otto engine parts are not designed to handle the extreme compression loads of Diesel cycle operation. Bolt together 2 Diesel engines, and it might work. But then you need a series of gears, with highly-loaded gear bearings and bearing mount structure, to link the 2 crankshafts. And heavy bolts. VW diesel head bolts were designed to stretch by a precise amount when torqued down. Sticking 2 diesel engines together means an adapter plate with two Diesel-grade head gaskets and an injector inlet, between the 2 halves. So long to one advantage of the purpose-built opposed-piston diesel, with one cylinder and no cylinder head/gasket. There are many, many more things which would have to be done; I'd leave it to a professional IC engineer; huge complex project far beyond the ken of amateur designer/builders who can do kickass conventional/traditional steam engines. If you're not a retired professional engineer who has designed a number of successful Diesel engines for major manufacturers, then I'd say forget it.

The idea of a steam version of the "Deltic" engine is tainted by its association with "Ken Wallis", who talked Bill Lear [of LearJet fame] into a variety of flagrantly obviously worthless steam power experiments, including a "steam Deltic engine", all of which were amazingly expensive total failures. Many years ago a few SACA Mugwumps talked me into interviewing "Ken Wallis" about his experiences with Bill Lear, who he served as Chief Engineer, with the idea of turning my interviews with him into an interesting historical article for the SACA magazine. He lived in a weird 1920s Spanish-style seaside San Diego California mansion close to me at the time, so I guess I was the obvious sacrificial lamb for such an assignment. So I dutifully VW-Beetled my way to his posh La Jolla address. After my brief attempts at friendly steam chat, I found "Ken Wallis" to be absolutely ignorant of even the most basic facts about light steam power, and a spectacularly evasive, obnoxious, and insulting jerk to boot. Later I learned that nearly every professional engineer in SACA had met the man during his late-1960s/early-1970s Bill Lear Steam Project days, and all of them had the very lowest opinion of him. It even turned out that he was not the noted/accomplished UK aeronautical engineer Ken Wallis, but merely a fraud who assumed the name/identity of "Ken Wallis" in an effort [sadly successful] to get idealistic but steam-ignorant Bill Lear to hire him. Apparently "identity theft" is not some new phenomenon of the Internet Age. To my knowledge, nobody knows what this disgusting fraudulent creep's actual name was, or where he actually came from. Apparently his [very nice] wife wanted to see the story told of her "illustrious but too modest" husband's experiences with the famous Bill Lear, so she arranged the meeting. Under wifely pressure, he agreed. But then he couldn't get rid of me fast enough. I don't think he wanted the REAL story to be told, by me or anyone else.

I do think that he was originally from the UK, but despite travels in the area I am not hip enough to British accents to narrow it down to region/county/"class". He spoke the Queen's English, but any clever guy can learn that, so I don't know. My British informants could have picked up on various things I don't have an ear for, but they weren't there.

"Psuedo Ken Wallis" [as Jim Crank once called him] was the only example of a steam guy I have met, who I did not like. Well, there was one other, an American. I will not talk about the other one, as it would bring back painful memories to many in the steam world, especially in SACA. Everybody else in the steam world who I have met, even those I disagreed with on many technological issues, I liked. Generally I am like Will Rogers; "I never met a man I didn't like". That's a sentiment which we need a whole lot more of in today's toxic political climate IMO.

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