Two-stroke engines

[mk]

I start this topic here, because the topic in the valveless forum isn't the suitable place.

Pieter, of course I would like to get more information about the big two-stroke diesel engine.

Bruno, could you also post a picture of the seven litre engine to me or to the forum?

[Pieter van Boven]

Hi mk,

Here are some other drawings of the engine parts. I also have them of the rest of the engine but I think it would be better to email them to you. If there are others who are intrested, please post a reply with an e-mail adress.

Pieter.

[jmhdx]

Thankyou very much for those pic's but the astonishing complexity of that engine is not what I was hoping for. I was simply hoping to remove the ignition circuit from an already simple engine. Still it will never be as simple as a valveless pulsejet, no moving parts, no corrosive parts= long life and zero maintenance.
Mike.

[marksteamnz]

Detroit Diesel by GM. All the 53, 71 and 92 series are 2 stroke. A Roots blower forces air in via ports in the cylinder wall. Exhaust via poppet valves in the head.

I start this topic here, because the topic in the valveless forum isn't the suitable place.

Pieter, of course I would like to get more information about the big two-stroke diesel engine.

Bruno, could you also post a picture of the seven litre engine to me or to the forum?

[Mike Kirney]

Those Detroits also came in 110 and 149 sizes. The largest production model I believe was the 16V149 (16 cylinders, 149 cubic inches each), which was used mainly in marine applications. The Detroits are legendary for thier power, efficiency, reliability and the fact that they could be repaired in the field without much expertise, or even proper tools or replacement parts. They are also famous for making a tremendous noise when running full tilt and a whole lot of smoke when starting up. There is some crazy rumour circulating that they can be converted to steam operation as well, but I'll believe it when I'm finished modifying my 3-71. There is even one fellow who claims not even to need an entire engine, but just some select bits and pieces!

[Anthony]

Detroit Diesels power some Canadian tanks.

[hinote]

There is some crazy rumour circulating that they can be converted to steam operation as well, but I'll believe it when I'm finished modifying my 3-71. There is even one fellow who claims not even to need an entire engine, but just some select bits and pieces!

I'm going to chime in here, based on my experience with steam power in the '70's.

The most basic, generic term for a piston steam engine is an "expander"; the steam doesn't give a damn if the engine used to be a 2-cycle engine.

The big deal is getting the engine to efficiently admit, expand and exhaust the steam.

Luckily, a 2-cycle piston engine has some characteristics that can make an efficient "expander" when converted to a steam engine.

In the '70's, we used Mercury outboard engines as converted expanders; the basic engine was cheap (when purchased as a used item), and we converted them to what is commonly called (among steam-power types) "bash-valve engines". The steam was admitted at TDC by a pin mounted atop the piston unseating a check-ball where the spark plug used to be; the exhaust was ported through the bypass ports into the crankcase, where steam oil carried with the (now cooler) steam lubricated the bottom end of the engine. The exhaust ports were blocked off, and the steam/oil mix exhausted through the "intake ports" cast into the crankcase.

This engine was worlds more efficient than the classic slide-valve, double-acting engine typified by steam locomotives in the late 1800's and the first half of the twentieth century, as well as the famous Stanley Steam Car. I was able to put toether a system that was efficient enough to condense every molecule of steam ever put through the engine of my steam car.

We put hundreds of miles on it, demonstrating the practicality of steam power for autos in the early '70's; I let my wife drive it to the grocery store by herself, and demonstrated it for the local SAE chapter at Cal Poly State University. I also "cruised" with the hot-rods of the time--now that was a cool thing to do!!

Steam power is fun--but so are pulsejets!!

Bill H.
Acoustic Propulsion Concepts

[Mike Kirney]

Well, yeah, steam doesn't care if its two-stroke or four-stroke but the old Detroit two-strokers are eminently covertible to steam because they have a poppet valve in the head and ports in the cylinder wall right near BDC, virtually identical to the uniflow steam engine that was state of the art during the 1930s-50s. It seems relatively simple to re-install the cam so that the poppets open just a little after TDC and then pipe steam into the 'manifold formerly known as exhaust'. The main limiting factor is the ability of the valve springs to hold the valves shut against the incoming steam pressure.

Thanks for sharing your outboard motor experience, Bill. As it happens I have a 1978, 1979 or 1980 3-cyl. Merc 500 that is getting harder and harder to start with each passing day. How did steam performance stack up against regular gas-mode performance with the Mercury? I would love to hear more about it. I am expecting to get about 20-30 hp out of my 3-71 on steam.

[hinote]

Well, yeah, steam doesn't care if its two-stroke or four-stroke but the old Detroit two-strokers are eminently covertible to steam because they have a poppet valve in the head and ports in the cylinder wall right near BDC, virtually identical to the uniflow steam engine that was state of the art during the 1930s-50s. It seems relatively simple to re-install the cam so that the poppets open just a little after TDC and then pipe steam into the 'manifold formerly known as exhaust'. The main limiting factor is the ability of the valve springs to hold the valves shut against the incoming steam pressure.

Thanks for sharing your outboard motor experience, Bill. As it happens I have a 1978, 1979 or 1980 3-cyl. Merc 500 that is getting harder and harder to start with each passing day. How did steam performance stack up against regular gas-mode performance with the Mercury? I would love to hear more about it. I am expecting to get about 20-30 hp out of my 3-71 on steam.

The bash-valve concept is a uniflow engine too-with an expansion ratio of way over 10:1. The old timers say you can't do that, but when the steam is admitted at the hot end and exhausted at BDC it works. Also, superheated steam at something like 600 F works in an aluminum engine too--for the same reason.

We dyno'ed the engine at 60 hp, but it took a bigger boiler to get that power than I was willing to carry. I recall estimating about 20 hp in my installation--not bad for a car that weighed about 900 lb.

Steam cars will never compete with the gas engine as we know it. The Rankine Cycle suffers from the heat of vaporization of water--you have to add it when boiling water to steam, and you have to lose it when you want to condense it back to water. Power plants get around this through regeneration, of course--but that takes a lot of equipment not practical to carry on board an automobile.

Remember, it's not the pressure of the steam that creates the power, it's the heat. Wet steam at pressure has no energy, as many have discovered. OTOH it's amazing how much power you can make with superheated steam at a surprisingly low pressure.

Bill H.

[Bruno Ogorelec]

I am pretty well educated for a dilettante when it comes to mechanical engineering. As such, it always comes to me as a delightful surprise to learn things I had absolutely no idea about. It was wonderful to read about 2-stroke steam conversions. I had no idea it was so simple (relatively speaking).

So, maybe the ultimate answer is in the pulsejet-steam combination. The pulsejet can contribute its super-efficient generation of heat and also the noise that the steam engines are so sadly lacking.

[larry cottrill]

I am pretty well educated for a dilettante when it comes to mechanical engineering. As such, it always comes to me as a delightful surprise to learn things I had absolutely no idea about. It was wonderful to read about 2-stroke steam conversions. I had no idea it was so simple (relatively speaking).

So, maybe the ultimate answer is in the pulsejet-steam combination. The pulsejet can contribute its super-efficient generation of heat and also the noise that the steam engines are so sadly lacking.

You could get lots of both from a good-sized Reynst Pot, and position it over the drive axle pointing skyward, for increased traction. And, don't forget a small diverter duct for cabin heat, of course.

L Cottrill

[Mike Kirney]

I have great faith in automotive steam power. I think it will be the first alternative source to come into play when the petroleum really starts to run out. Jay Leno of late-night talk show fame says he loves his Stanley Steamer and has been ticketed doing 75 mph in it on the freeways around L.A. The Doble steam car was also one of the fastest and most powerful sedans of its day. It might have had more commercial appeal if it was not enitrely hand-built from exotic materials, and so was only affordable to the ultra-wealthy (Howard Hughes used to cruise America's highways at 90 mph in his). My diesel conversion is for a stationary electrical generation installation. Even running on diesel, the 3-71 is damn heavy for its mild horsepower (1500 lbs./113 hp). Of course it probably produces a lot more torque than lighter yet higher revving similarly-sized 3.5 litre gasoline engines. I need to make about 50 amps at 600 volts 3-phase to run my shingle-making machines-maybe more maybe less depending on how I split up the production steps. I called Hydro One last year about getting industrial grid power but it's astonishingly expensive. It seems like a major gouge unless you are grossing millions of dollars a year. You have to pay a subscription fee of thousands of dollars each month whether or not you use any energy. I can get a full cord (~3.5 m3) of cedar slabs for 20 bucks so you can see why I am so interested in this steam business.

[Mike Everman]

"shingle making machines?" I am not laughing, I swear! Not AT you, Mike. I'm just pretty certain I've never known anyone to say that, or that they need steam power to run them. Thanks, man.

[Mike Kirney]

"shingle making machines?" I am not laughing, I swear!

Laugh away, Kazoo-Man. Last year a pack of crap-grade cedar shingles was going for 9 bucks at Home Despot. This year the same item costs 23 dollars!!! First quality shingles were 88 bucks for 100 sq. ft. last year. I haven't priced them this year, but I betcha they're over 200 bucks a square right now. I own all the machinery needed to manufacture cedar shingles - basically a collection of circular saws - one 60" to cut the logs into 16" bolts, a 36" bark stripper, another 36" circular saw to slice the bolts into shingles, and another saw to clean up the edges, plus a sorting bin, strapping rig and thousands of labels that say "Shires' Shingles" on them (even though my surname is Kirney).

[marksteamnz]

Sheesh I miss a day's postings and it all turns steamy. <VBG>
In Northland New Zealand Collins brothers sawmill uses it's off cuts and trimmings to feed a boiler that runs the steam engines to power the mill and produce electricity for all the services.
It's also a tourist attraction so city folks can see timber milled and marvel at the steam power.
So Mike you're on to a winner. Just keep the Jimmy's sump insulated and hotter than 212deg F and you won't get a yucky water oil emulsion in the sump which is no good for bearings.

Bruno Steam cars LACK OF SOUND! Different sorts of sounds PLEASE! It's a naughty secret that yes a Steam car can be quiet as any electric, but if you get it wrong the most wonderful ear splitting bangs from backfiring burners are avaliable. Then there is the howling banshee burner wail of a Stanley being run hard almost as good as the whump rumble of a 8 gallon per hour nozzle cutting in on a Doble boiler.
Ahh memories
And yes the single cylinder Detroit Deisel steam engine is more than just a very cunning plan. Pictures soon.....ish