Many of us take for granted that we have an understanding of the Otto four-stroke cycle, but we had to learn it somewhere, and wouldn’t it have been easier if we had learned it on an ingenious, sturdy miniature engine that was surprisingly true to form? The W.M. Welch Scientific Company tried to teach students about the combustion engine’s intricacies by using the hands-on approach.
There is surprisingly little background information out there on the W.M. Welch Scientific Company. According to a website called analogweather.com, they were founded in 1880 in Iowa before moving to Chicago in 1906 as the W.M. Welch Manufacturing Company. At some point, they were renamed as the W.M. Welch Scientific Company before merging with the E.H. Sargent Company to become Sargent-Welch. Their website now seems to be owned by Ward’s Science, which sells educational supplies to science educators.
Mr. Welch seems to have published a book called How to Study: A Guide for Self-Improvement in School and Home out of Chicago in 1889, so education was definitely a goal. The company wasn’t limited to school supplies, however, as they also had a “Furniture Factory.”
So how did I end up with this engine about which I can definitively ascertain little? Proving that there are still good people in the world, a friend of mine at work was able to pick it up for free, and seeing my reaction to it, he decided that I would probably give it the best home.
How does it work? It has just about everything a real engine has, including this “distributor.” A positive lead is hooked to the knurled knob that feeds current to the “rotor,” and a negative lead is attached to the block itself as a ground (you can barely see it at the top of the picture). The metal strap that takes current from the positive terminal is attached to a rotor “button.” As the rotor rotates, it makes contact with four metal buttons that are connected to the “spark plug wires,” just as it does in a real distributor. You can even move the timing mark to show how advancing and retarding the ignition affects the spark in relation to the piston as it approaches top dead center.
The spark plug wires are each connected to a metal tab that makes contact with a mini bulb. This was the hardest part of bringing this engine back to life; the bulbs were burned out, and they are an extremely odd size (GE 136). Luckily, I found something that would work at a local hardware store that has been open for decades (and merchandise is there until it sells; I’ve bought products that had been for sale since probably the late 1950s). The only rub? If you hold the cylinder at TDC long enough, the bulb will start to flash; that is what the ones I bought were designed to do.
The engine mimics an L-Head four-cylinder with a visible camshaft and valve springs. The exhaust valves are red (because they’re hot, obviously), and you can see the springs through cutouts in the block. If the color doesn’t grab you, the valves themselves (in addition to the cylinder number) are clearly labeled, as is the firing order.
Here’s a closer look at the bulbs, the contacts, and the valves. One of the best parts of the engine is that the pistons are made of wood; you can see them coming up to TDC on cylinders two and three right here.
Another thing that my mild obsessive-compulsive tendencies would not allow to stand was the cam timing. Each lobe is adjustable and locked down with a small set-screw, and they were not even close to being in the correct places. Therefore, I adjusted each one to a position that would allow a minimum of valve overlap at TDC; please don’t tell me if I got something backward.
Even the crank gear and the cam gear resemble a real four-cylinder engine’s; the only difference is that you’re driving the crank rather than the crank driving the car.
And this is how it looks when you turn the crank (also notice the distributor rotor turning on the back side of the engine). I use an AA battery to provide power to the bulbs, and that’s all it needs.
What makes me happy is this: There were certainly kids who would have studied this endlessly until they figured out exactly how everything worked, and auto shop teachers would have been able to answer any questions that would arise. It’s just such a simple but effective learning tool that involves a lot of critical thinking; with a little classroom instruction ahead of time on the fundamentals of “suck, squeeze, bang, blow,” the kids could have spent a class period or two figuring it out in their own heads. It’s probably not flashy enough today to work, which is a shame, because no YouTube video would do any better.
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That’s the coolest thing I’ve seen in years!!! And in like new condition! Unfortunately, the closest kids today would get is to watch the video on their cell phones.
There are a lot of “car people” today who never built the Revell Visible V8, and it shows.
I still have my Visible V8 I built back in the ’70s 🙂
The Visible V8 was the first thing popped into my head when I saw this.
Loved it.
I never built the Visible V8. It cost too much … I didn’t have the willpower to save for months when I could use my 25 cents a week allowance to buy an AMT 3 in 1 kit for $1.49, every six weeks. Though I still had to scrounge a few pennies for sales tax. And more than six weeks if I succumbed to buying a Hershey Bar or a pack of gum for a nickel. But this one is very cool.
Yup. My thoughts exactly. Couldn’t afford it. Couldn’t afford the Visible Man/Woman model either, although I wanted those very much as well.
I did eventually get a visible Wankel engine model. I think it was on sale at an after-Christmas sale at the hobby shop. That was probably one of the coolest models I ever had/built.
https://www.scalemates.com/kits/renwal-811-visible-wankel–194414
My visible V8 came from a garage sale, and lacked instructions and several pieces.
This irony explains a LOT about my mechanical knowledge…
I’ve seen a re-issue of the Visible V-8 but it has to be cranked by hand. The version I built back in the 70’s had an electric motor that “ran” it. Still, very cool 😎
The visible V-8 was one of my best Christmas presents ever.
Oh yes. Two of my holy grails are the relatively rare chassis and transmission Renwall built for this, and the even rarer Slant Six that Revel built in 1961 as part of their brief flirtation with Chrysler, complete with a guidebook by Chrysler engine guru William Weertman.
That is way cool! I want one!
Interesting teaching tool .
I like it but don’t want one .
Similarly I was recently gifted a large red ABS suitcase that contains a nice SUN brand tune up kit, dwell / tachometer, 12 volt inductive timing light, remote starter button and compression tester .
It looks unused and when I asked what I owed he said, nothing, not even shipping, you’re the only guy I know who knows what it is and who will actually use it .
-Nate
Aaron, what a great find/gift. Your friend was absolutely correct that you’d give this device a good home. Writing about it is a terrific way to preserve and celebrate it.
I love these sorts of things, and see similar devices illustrating other parts of automotive mechanical infrastructure at my work with a local automotive tech program. These mechanical models of course are generally gathering dust relative to their modern equivalents…computer animations. But you’re exactly right in calling out the hands-on learning part of this. Frankly, students don’t (or shouldn’t…that’s a longer discussion) wind up in automotive tech programs to watch videos, and before turning them loose on actual engines, transmissions, etc. models such as these are important ways to see and touch the technology that they aim to work with. Same goes for any subject for that matter…we’re just interested in auto tech here.
Which brings me to Welch Scientific. Yes, most of these “science supply” companies have collapsed into each other with mergers due largely to shrinking markets. Sad but true. I could really go on and on here about this stuff as I absolutely adored this sort of stuff as a student and it was what motivated me to explore a life in science. The fact that I didn’t wind up doing actual lab science somewhere is largely due to the fact that science became much more hands-off and more theoretical as my study of it deepened…and well, that put me off. (and “trades” were absolutely frowned upon in my family upbringing) Again, another longer story. But I so recall equipment from Wards, Welch, Edmunds, Carolina Biological Supply (all collapsed together into what is now Ward’s Scientific) in the school labs and science rooms of my youth.
I found an old archived link that explains more of the back story of Mr. Welch. I’ll quote a bit (link at the end) as getting to the link is kind of gnarly:
Anyway, it goes on and is a fascinating corporate/educational story for those who want to geek out on this stuff.
https://archive.ph/20120910115838/http://www.sargentwelch.com/article.asp#selection-687.0-691.185
Thank you so much for sharing this cool model!
This is fantastic. It is quite well made. Thanks for sharing.
You’re welcome (both David and Jeff)!
My 8th grade science class had one of these! It wasn’t in great shape and the teacher wasn’t excited about it. The school also had a working model of steam locomotive adjustable valve gear (probably worth a few bucks today).
The Germans had a somewhat different and much more elaborate model to teach would be drivers about operating a car, if not the engine – the Hohm instruction car.
Unlike your model, the engine, although accurately detailed, had no interior parts. Instead, it housed an electric motor that drove the driveline through a working clutch and gearbox, with cutaways to showcase both, as well as the differential. There were working brakes, steering, and lights as well.
This is the postwar model, the original 1939 model had a front grille clip like an Opel Kapitan, with a vertical Hohm nameplate.
One thing that may not be clear from the picture is how big these were – about 3 1/2 feet long. I’ve only seen one of these in real life, and it wasn’t for sale. About 7,000 were made in total.
Here’s the front clip of the 1939 model.
That is wild. I would love to see it in action, but the grille and headlights are the stuff of nightmares. 🙂
I just want that! Gorgeous thing.
Very cool device.
My holy grail is building a version of the Meccano Motor Chassis, this is a very early 1920s version.
There were different plans for it made up into the 1970s.
You needed the top level No.10 set to build one, an expensive “toy” back in the day.
Here is a much later version, they feature working suspension, Ackermann steering, drum brakes, gearbox, differential, engines can be clockwork or electric.
I’m sure it takes quite some skill and fine tuning to get everything working correctly.
Oh, my! Being youngest of too many, I never had anything even remotely resembling a full Meccano kit. Instead, I had lots and lots of mixed bits (not to mention nicked bits and nixed bits), and thus the dreams of making full Meccano jobs like in the books remained just that. Well, that and such marvels as the one chassis-rail three wheeled engineless Bugatti build of the Bugatti-esque model shown here…
I love this! And I had no idea that such a thing ever existed.
You also remind me of the things I love that fill my basement, but that I need to find new homes for.
I had a car chassis kit. It was about a foot and a half long and included the frame, steering gear, visible three speed manual transmission, drive shaft and visible differential. No engine however just a crank which you could turn and see how the transmission and differential worked. It was a Christmas present when I was 11 or 12 and I think my choice was the chassis or the previously mentioned visible V8.
What a sweet, sweet device this is. It would have been of immense help in explaining how/why spark advance worked when I was a kid, because that was a real rub-your-tummy and pat-your-head thing on paper.
Now I just need one which demonstrates how variable valve overlap stuff dispenses entirely with a throttle on BMW’s (and probably many other cars by now), not to mention about thirty other miracle devices on modern engines…
Actually, I have another secret reason for wanting this little machine. I am, for my sins, an inveterate fiddler (I think these days it might be called stimming): I must always have something clicky or moveable or adjustable to hand whenever I’m sitting still. As of right now, it’s the nail clippers, for example. This engine device would be so permanently satisfying that all the collected click-clackeries I have secreted about the place could all be dispensed with forever, to the benefit of on-going household peace and humanity (eg: no more yelps of “what the hell did I just sit on?”)
I got it now. If it’s any consolation, that definitely doesn’t only happen to you: It’s just that being in a different time zone, it’s more likely to happen at times when there’s no one logged in to fish it out of the overzealous spam filtration net.
I inherited one of these from my dad. He taught physics for 40 years. I just used it to show my engineering students how pistons work. I’ve got them working on making the bulbs light up.