Science/Engineering/Technical forums

If I recall correctly, they run about 800-1000 rpm. They've gotten to be popular for generators because they'll run on anything, and they run cool and quiet. I was going to use one for a genset a few years ago, but never got around to it. They aren't real powerful - I think I needed a 2 cylinder version to run my 16kW generator. I'm not sure of the exact ratings anymore, though.

Here's a list of currently available new diesels at Burdin's surplus center.
Note prices -- you pay a lot extra for a "classic".

I don't like them till they get to be water-cooled, myself. That sound of gargling rocks diesels have gets to me. Sad thing is that those tend to be much too large for a home generator, or at least my home -- I'm not running water heaters and so on, and have determined that about 5-6.5 hp is the sweet spot, at least for normal 4 cycle gasoline engines. Less, and there's not enough and it's working too hard, more and it's loafing and wasting gas in friction and low net compression ratio. I suppose you could run any of these more modern engines slower and gear them up a bit to get either 60hz from an AC generator, or to spin the about 4k rpm my old mil surplus fighter plane 24v dc generator likes. That would effectively cut the horses down to about the right number and have the engine running nearer the torque peak, where any engine has the best brake-specific fuel consumption and bonus, it'd probably live longer.

Secondary use -- heat with the hot water you'll produce. Just arrange to dump the waste heat into your basement in winter. I've done this (actually had a generator inside, in a box with a huge fan, even collected heat off the exhaust) and in general, it's enough heat, but I don't reccomend that -- fixing the thing inside the box is a pain, and it's kinda dangerous to have a running engine (and fuel!) indoors -- I made it work in desperation, but I'm no longer that desperate. It did save a ton of money when I needed to do that.

Now, my needs are a lot different than most. My generator never has to handle the peak loads the buildings can produce, ever. It's just charging the big batteries which provide all that, and for me the DC generator works out a lot more efficiently than an AC one that has to then run a battery charger -- fewer conversion losses and no power factor issues (battery chargers off a normal generator draw current and torque only on the sine wave peaks! -- horrible. Even my 20 hp Hobart welder doesn't like it when I turn on the big machines if it's driving them directly. But it's far too much to use as a battery charger -- those things don't like to see huge currents, and like to be charged at C/10 or so max for best life.

Come to think of it though, a big welder might make a nice backup if you use the welding output DC to charge batteries and can adjust that so as not to put in too much current.

I would recommend what I'm doing if someone wants to be serious about the infinite un-interruptible power system though. Trying to run off a generator 24/7 is going to kill it and you both.
And that peak vs average thing means you need a much larger one, which will be very wasteful. At least the power company gets the laws of large numbers working for them, though not perfectly; everyone bakes on Thanksgiving and runs the AC when it's hot, but at least those changes are slow and pretty predictable, and they can spin up other generators when they need them as demand builds. Trying that at home would be more expensive and complex than the battery/solar panels/inverters are, and much less reliable -- very hard to keep in sync.

Orion Birch should be coming along at some point with his adventures with diesel and biodiesel. One of the guys at his commune makes the latter in large quantities, and most of the people there are driving diesels he's built for them. He gets really on the metal, the only electrics are for the lights and glow plugs...tiny alternator and battery to save weight.

The advantage of the old listers versus the little diesels it the speed that they run at. Many people have the listers running about 300RPM. These things will run 24/7 for 20+ years with nothing more than oil changes. Also the large flywheel takes up surge loads and also makes for a smoother output. Plus I have seen the things ran off of stuff like flax seed oil makes them good for emergencies.

Kubota makes a nice little diesel. I used to work on their small lawn tractors that had two and three cylinder diesels and those things ran real sweet.

Hi, Ok, Ya'll correct me if necessary. On one of the youtube videos on "Listeroids" (I think the data was in a video, not something I read), the guy mentioned that his one cylinder "listeroid" (around 6hp I think) ran for three hours on a gallon of diesel. The smallest watercooled diesel that is mentioned in Dougs link above (a 13.4hp one) uses 0.51lbs/hr/hp or around 6.83 lbs per hour. A gallon of diesel weighs 7.15 pounds. If that guy is telling the truth, the "listeroid" (at about .4lb/hr/hp) is more efficient that a newer model? -bill

Burdins has those 3 lungers once in awhile, but being a surplus house, it varies. Usually around 1300-1500 bucks and some missing pieces (exhaust or radiator fan is almost always missing from those). They seemed too big, but mebbe if run real slow, you'd get some of those long-life benefits? Seems to me, at least with cars, that sometime around the '90s, engines suddenly got so much better that now 100k miles doesn't really break them in, and I'd hope that would also be true for a real diesel? I know it ain't for Briggs (even though they got a lot better when mitusbishi bought them, they're still no honda or even close).

Not more efficient, not even close. The thing is running an alternator is often a variable load and depending on your usage can be at idle or low load for quite long periods where these slow running engines really shine. If you were running a generator as a sole source of power one of these engines would be good. But in a situation like Doug's, where he is charging a bank of batteries I believe the small high RPM engine would outperform it due to the pretty constant load.

Even at the national average of 14000 miles a year thats only maybe 300 to 400 hours of actual run time, which compared to a stationary engine is not much. It will do that in a couple weeks running something like a pump.

Jerry has that one right on -- it is so easy to run up the hours it's not funny, and we have some results from over the years:
Techumseh -- 300 hours, dead. Not that great while alive.
Briggs (the old ones) 300 hours, change the ex valve, 600, dead.
Briggs IC -- about 3 times longer.

Honda - 14,000 hours is the current record, running straight 30 weight, non detergent (which was also tried on the others, and it's a lot better if you don't have an oil filter). By then it was burning a lot of oil but I've had three to over 10k hours.

And that's just backup use (but for decades -- I used to need a lot more than I do now). Trying to live just on one, I can't imagine that. Electricity from you average store generator is about 2 bucks a kwh if you figure all the costs. And noisy. No one can stand that for long.

What I've found with Hondas that's bad, is they press on the cam drive gear, and if you use slick 50, it will come loose. It's not a clearance engine, so that's it for one if it happens to you. Too bad, as that gives you about 10% better performance than oil alone. There is a Chinese copy of the Honda OHV engine that is a good copy (and at half price) - and it has the same darn problem.
I hear the Honda OHC engine isn't so great. From them.

In my situation, I'm running a dyno more or less, so I tried to learn about all that. Gasoline engines do best in KwH/gallon at torque peak and full throttle, as that's where they have the best compression ratio and least valve losses.

If I understand right, with a diesel it shouldn't matter as much what the rpm is as they are "wide open" for air all the time, and just vary fuel flow. So, correct me if I'm wrong, but if I get a 20+ hp one, but only need 7, could I not run it slow, still have efficiency, and just have less power output? I'd lose some in the drive to the generator of course, but I already do, and that DC generator with belt drive kicks butt over an AC generator with even a sophisticated (inverse inverter) battery charger in power per gallon. The inverse inverter is a lot better than a transformer/diode charger, as it draws current through the entire AC cycle, with power factor close to 1.0. But still, running at 3600 rpm is poison for a gasoline engine and I suspect a diesel too -- too many piston-miles. So far, that seems the limit on a quality engine. I've not worn main bearings out yet on any.

There is alot of that kinda stuff out there. We don't that much out here aside from some antiue locomotives near the shop. It's all cool. I love old power!

Hi, Found a useful function in ebay (Classifieds). Maybe you all already knew about it, but seems useful to me. You can search for classified items near your town. I know ebay has always had a search by zip code function, but haven't tested to see if this is different. This is useful for heavy items that no one wants to package or it plain just costs to much to ship. Here is a recent item I found near me that kinda fit in this category:
http://greensboro.ebayclassifieds.com/a ... ut=gallery This function might be useful to look for big vacuum chambers, x-ray systems, or electron microscopes. etc. -bill

Hi, Found the elusive 8-1 Listeroid (GM-90) and matching Indian 7.5kw synchronous generator. These are new old stock, never been run. I am now looking for baseplate metal and accessories (Radiator, pulley, belts etc.). May add a 24v alternator or generator (maybe for electric start); in case I want to be ready for a partial solar setup. -bill