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From the Dust Bin of History – Intriguing Mystery V-Twin Engine

V-Twin Mystery Engine

Updated – Every once in a while during the pursuit of the history of the motor vehicle, something unusual crosses our radar screen. This large water-cooled V-Twin engine with several unique features certainly fits into that department.

Little is known about the power plant, other than the photos originate from the NAHC, Detroit Public Library archives. The images by Spooner & Wells, Inc., photographers at 1931 Broadway, New York City were likely taken in the area. The engine appears to be circa 1908-1915. The lead photo shows the timing side of the engine and the lower images the output end.

One of the features of note behind the open cam and magneto drive, is a pair of very unusual intake runners with expansion chambers located between the carburetor and the intake manifolds. The fuel and air mixers feeding this induction system are of the auxiliary air valve type and the spring-loaded valves are next to the camshaft gear.

Unidentified V-Twin Engine.jpg

  • Drive side view of the engine, water pump driven by the camshaft, and the backside of the magneto. 

Update I – The ignition system is also of interest. The simple magneto without a distributor appears to be driven at two times engine speed. The mag also has a double ignition point housing on the backside much like Bosch used on some of their units, which can be adjusted to vary the ignition timing. Many V-Twin magnetos and battery ignition systems fire the spark plug near the end of the compression stroke and also a wasted spark at the end of the exhaust stroke.

The holes seen on the sides of the cylinder heads are interesting. Both could have been used to get the core sand out of the casting and then later filled w/core plugs. There is also the possibility that the pair of holes on the drive side might have been used for the exhaust ports? Another scenario is the exhaust may have passed through passages to the sides of the heads.

The engine is also quite interesting due to its advanced design features that include: lightweight o.h.v rocker arms and overall general construction, pushrod guide bushings on the side of the intake manifolds to help prevent flexing, and the long studs in tension holding the heads and cylinder barrels to the crankshaft. Possible uses where for aircraft, automobile, cyclecar (like the GN seen below) or a large motorcycle engine like that in the North London Garage Special. 

Update II – The patent for this engine appears to have been found, learn more at: Mystery V-Twin Engine Solved – 1909 Gibson Patent Discovered. Please let us know if you can add more to this story.

The images were located by vintage casting expert Lee Storr, who engineered and oversaw the Frank Lockhart Miller racing car intercooler replicas covered earlier here in a three-part series.

  • A gentleman holding the engine shows its light weight construction and also serves as a size reference.

Mystery Engine III

  • An English GN 200-Mile Race cyclecar with a similar-sized engine that is a 4-valve per cylinder o.h.c. unit, which passed through our workshop a few years back. 

GN Cyclecar

46 responses to “From the Dust Bin of History – Intriguing Mystery V-Twin Engine

  1. Very interesting engine. The car that carried it would certainly have stood out from a styling perspective. The wide V shape would have required an unusually broad radiator and hood configuration during a time when car builders were incorporating increasingly narrow hoods and radiators.

  2. It’s too wide to be a motorcycle engine, but some European light cars from that period had similar looking engines where the heads protruded from the sides of the bonnet.
    It’s more likely to have been intended for marine or even aviation use, possibly as a prototype for one cylinder pair of a modular design for airship or aeroplane use. (Or as a twin for lighter aircraft.)

  3. Doesn’t appear to be John Alfred Prestwich. Looks too big to be a moto engine, with what appears to be a 90 degree V would give it nice balance; perhaps its a light aero engine. Could that be Glenn Curtiss? The long studs holding the cylinders to the crankshaft resemble some of his early designs.

  4. Looks along the lines of some British Anzani motors. He did some aircraft and boat motors ? Are the bolts British or American thread?

  5. David, This is a very interesting engine. It seems very likely that this was experimental, since the photos were taken after running it. The spark plug wires seem to originate near the camshaft making me think that there is a timer there, but I can’t make sense of the high speed magneto other than to get sparks timed for the 45 degree cylinders (with wasted sparks as you said) with a flat crankshaft and there seems to be an advance on the mag; very confusing. There doesn’t seem to be any fuel supply; we’re used to seeing float chambers, assuming that the carburetors are integral with those high speed valves. Could it be that this ran on natural gas or the like? There’s some device behind the camshaft gear with a spring hanging loose from it. I also notice that the flanges for mounting the engine are not symmetrical for mounting it longitudinally for a propeller or prop shaft, but rather transversely in a cycle car or motorcycle. Also, since there is no visible way of mounting exhaust pipes, I would suggest that the “dummy” exhaust ports on the intake side might accept large C clamps for holding them in place.

  6. I have looked through many aircraft engine books, including the 570 page Airplane Engine Encyclopedia by Glenn Angle, and I have not seen this engine. It’s got me stumped at the moment.

  7. Hi David,
    Very interesting! I think it has 3 valve heads. If you look closely at the photo taken from the timing side you will clearly see that between the two exhaust pushrods is the single inlet one. You will also see the inlet rocker a little lower than the exhausts, with its mounting. This would explain the four exhaust ports. The ones on the timing side do appear blocked however.
    Although they seems too small, are those auxiliary ports just above the water inlets?
    All the best, Mark

  8. David
    A possible explanation for the ‘blocked’ exhaust ports: The heads are identical castings with the exhaust valves opening into an internal closed chamber. The casting has external ports on both sides. Which ever port is required is bored through from the outside into the closed chamber.
    Mark

    • Mark, Thanks for all your input, I had thought about that, but then wondered where else the water jackets could be? It is quite an interesting engine to just ponder how it operated! I hope someone comes up w/the story about how it was constructed.

  9. David, talking about V ‘s , what truth is there in the story I heard last night a Christie V4 race car is soon on the way to be on the road?

  10. For what it’s worth, the six-bolt pattern on the drive pulley looks very much like the pattern that’s been standard for wooden aircraft propellers since forever.

    • That was my initial thought. I’ve been searching quite a bit on this one and haven’t found anything resembling it. There were a good 40 or 50 cycle car makers in the U.S. at this time, so its nigh on impossible to narrow this down to one. By the mounts it could have been situated in line on a car frame with a series of chain drives which would make the side exhausts convenient. IMO this 90 degree motor looks a bit too big to have been in a motorcycle. As for it possibly being an aero engine, I’m still trying to imagine what it would be applied to, a light biplane perhaps? Curtiss supplied one of his V twin motorcycle engines to be used on an early airship, but that was air cooled. By this presumed date virtually all of the inline and Vee type aircraft engines were liquid cooled. I cannot shake the impression of this looking somewhat like 1/4th of an OX-5, or other aero V8. Whatever it is, it is quite sophisticated, this was no backyard operation, the expansion chambers look like they came off of a contemporary motor, and the aluminum (or magnesium) castings are complex and of high quality.

  11. I don’t know what this is.

    Some thoughts:

    I date the clothing and hat to ca. 1900 to 1910.

    This could be one of a number of early non production v-twins for which I have ever been able to locate a picture. Some by famous names, others by skilled but makers which are nearly unknown today.

    The intakes varying cross section has already been commented on, I wouldn’t be surprised to find a patent filing.

    I think you could get to six bolts on the output flange by engineering optimization and good design rather than matching a standard. Note the large gear in the magneto drive has six bolts and what looks like six rivets.

    I think this may well be an aviation motor, but quite possibly an airship (lighter than air) rather than aeroplane motor.

  12. First, This has none of the earmarks of ANY John Alford Prestwich engine that I have seen in antique Motorcycles, —be they V-twins or singles dirt , grass, or Road application. The rocker arm lightening holes indicate aero use. The flange also indicates a wooden PROP. The intake chambers, to me , appear to be augmentation — Tuned Expansion but not like a RING DING , as this engine appears, (as a four stroke) to be a ONE trick pony, RPM wise, ALSO indicating a prop application. I ASK: IS this in lieu of carburetor & Am I looking at a TUNED fuel injection setup ??? After all, the Wright Bros. Flyer WAS fuel injected! Am I looking at some form of 2 Atmosphere valves in series at either end of each exp. chamber??? Am I looking at 2 exhaust push rods ??? for 2 exhaust valves ??? This is one engine that I would like to see in PERSON as it really IS fascinating !!! Expansion chambers on an early engine for WHAT-Ever reason , means an awarness of TUNED induction resonances! props can ONLY go SO fast, and also means that the ones on later ring-dings have borrowed a very old technology and called it “modern”. It hints to me that someone knew cylinder head FLOW techniques, well, a very long time ago! The “mystery Blank hole MAY be for pointing the exhaust the other way, depending upon application. Diesel became popular on lighter than air ships because of NOT having high Voltage corona and flash over problems in a sometimes leaking Hydrogen & air,together = BOOM! This engine indicates significant research and is NOT “BUSINESS AS USUAL” . Edwin – 30 –

    • It is intriguing. The intake runners probably help with fuel atomization, which makes sense given how primitve carburetors were at the time. But they also could have served as intake (Helmholtz) resonators. if so, this is extraordinary as the use of expansion chambers on two cycle exhausts didn’t happen until the mid 1930’s in Germany.

  13. Ok , after studying the photos over and over this is my best guess this engine definitely has three valves in the head. A smaller rocker is pushing on a device which maybe an injector or let’s call it an atomizer. I believe those huge scientifically shaped intakes act as a precharge chamber for the air intake to swirl or vortec the air. Could there have been a pressurized fuel tank? Possibly hand operated. Could there have been a natural gas chamber of some sort (hydrogen? There have been crazier things). With the absence of some fuel bowl or similar device one would have to assume some other type of delivery system. The devices at the inlet of the intakes have me stumped. The one seems to be effected some how by the crank with possibly a governing device. The other(left side of the photo) doesn’t seem to have anything reacting it except possible back pressure . Whomever produced this engine seemed to be very advanced or trying new things with the assistance of a thermal engineer. I know I probably way off but maybe this may spur some other thoughts to rediscover the inventor.

    • I agree with your comments about the intake, either this wasn’t 1915, or whoever built this was an engine savant.

  14. The magneto does NOT run at twice engine speed. The single intermediate gear has no influence what-so-ever on the overall gear ratio, only on rotation direction. You could include as many intermediate gears as you like, as long as they all have the same tooth count, the overall ratio will be determined only by the first and last gears in that particular drive train. The magneto runs at normal 1/2 engine speed, nothing unusual there. Intriguong engine nevertheless.

    • Piet, Stone the Crows and I have taken another look at this, 2-times the engine speed is correct. I relied on another knowledgeable enthusiasts thoughts on this in the rush to make a deadline and should have double checked it. As a long-time engine and gearbox rebuilder I am well aware of the actions of idler gears.

    • Agreed that the intermediate gear only reverses the mag rotation. The speed the mag runs is determined by the number of interrupter cams in the mag, (and therefore how many sparks per revolution of the mag) number of cylinders, and by the arrangement of the cylinders and crankshaft. A two cylinder four cycle engine with cranks in line requires the mag to run at the same speed as the crankshaft so that you have one spark per crank rotation. In a two cylinder motor having cranks 180 degrees apart the firing is irregular and the mag (with a single cam interruption) would have to run at twice the crankshaft speed. Normal procedure in this case would be to avoid undue wear and tear on the mag and so run a two cam interrupter at crankshaft speed which would provide two sparks per revolution of the armature. With a two cam mag a 2 cylinder motor with inline cranks would run the mag at half crankshaft speed, for two cylinder cranks 180 degrees off the mag would run at crankshaft speed and the same mag would run at half crank speed for V type two cylinder engines. It’s been a few years since I learned my gear ratio and proportion equations, but this mag appears to be driven by a larger gear and is set up to run at twice the engine rpm meaning it has a single lobe magneto interrupter cam.

  15. The photographs are stamped on back as taken by Spooner & Wells, Inc. , photographers, 1931 Broadway, New York. The photos are with many others from the 1909-1910 period.
    The deep sump makes it unlikely to be a motorcycle engine.
    Marine engines were not usually V Twins and they normally had big flywheels.
    There were lot’s of big, watercooled aircraft engines by 1910, but a V Twin would normally have been aircooled as the extra weight of the radiator would not make sense on a twin cylinder setup.
    All the aircraft engines of the period were pretty well recorded, even obscure, one-offs like the Christie/Hamilton V8 made it into the literature. But not this thing.
    So maybe it is a cyclcecar engine. As the gentleman above says, there could be a patent out for this. It looks like somebody thought they had a great idea.

  16. I collaborated with a good friend of mine who is a product engineering rep from an unnamed automobile manufacturing corporation. He believes it is a aircraft engine, hence the lightweight design. And he added an interesting point that the holes in the sides of the castings could be there to ad more cylinders to the design. It was not uncommon to have 4 and 6 cylinder configurations in early aircraft. He agreed with me that the intakes are very advanced for the period and may have been an ad on at an attempt to get the engine to run. Also the carbs are of aircraft type. I have never dealt with any aircraft so they looked alien to me. I would tend to agree with the aircraft engine because lightweight didn’t seem to be the primary concern in the automotive world during its infancy.

    • Good points, aviation engines early on pioneered what are commonly referred to modular components today. The amazing Duesenberg aero engines, and I think the Sunbeam Sikh, had individual cylinders and heads rather than having them mated. And certainly the Curtiss OX series engines were built with the good use of common interchangeable components. I had had been thinking that this was a two cylinder version of a larger V8 or V12, as in the experimental V-2 that was built from Liberty components, but it is a point well taken that this could be the opposite, which is a testing of the individual cylinders and heads before scaling to larger units.

  17. Does anyone else see what I think are auxiliary exhaust ports (visible on the drive side of the engine)?

    Less frequently seen on water cooled cylinders, usually partially intended to address exhaust valve and valve seat problems at the time. Which could have still been an issue with liquid cooled engines at that time. Are there coolant fittings visible on the heads in the drive side picture?

  18. WOW -talk about a who-dunnit. it makes fascinating reading but it’s way out of my league when it comes to engineering analysis.
    fascinating to read all of your followers theories.

  19. I found a patent that seems to cover this engine. Arthur Hugo Cecil Gibson, a subject of Great Britain and a resident of Manhattan, NY applied for a patent in 1909 for what appears to be this very engine. US Patent 1146864., granted in 1915. It is a four stroke engine but the piston is stepped to also act as a pump or compressor piston. The two large valves on top of each cylinder are actually a normal intake and exhaust valve. So the intake and exhaust pipes are not shown. What appears to be tuned expansion intake pipes are actually part of the compressed air system. According to his patent, Mr Gibson intended the engine for aviation work or other purposes where minimum weight was desired.

  20. more thoughts….
    The holes at front and back of the heads are most likely welch plugs or core plugs for sand removal from the water jacket core as in most liquid cooled engines.

    water enters the engine from the water pump as shown, and appears to exit from fittings at the highest points of each head, makes sense.

    according to the patent application drawings, the exhaust port outlet is opposite the inlet port, this would make the exhaust port out of view on drawings and photographs.

    The third valve ….. if I made an engine if this size I would most likely incorporate a decompression valve, consider…..

    There was a comment on a flat plane crank…. a V2 engine can only have crank with one big end, hence the fork and blade conrod design and variations.

    has anybody had any more thoughts about why the Maggie is running at twice engine speed…. once every 180 degrees . on a 90 deg V2, the bangs occur at 270 and 450 deg. apart, or 90 and 630 deg. apart….. lots of phantom sparks.
    over to you…..

  21. what I hypothesized about the ports/ welch plugs….. may need a little more revision….
    But I welcome comment….
    b

  22. a gentleman in the united states supposedly took a Harley knucklehead v twin and designed it with liquid cooling. which looks identical to the one in the picture. they call it the drake engine. though I think the family discredits it ever being a Harley. that’s still in debate. I say drake just took a Harley knucklehead and designed a jacketed set of jugs and incorporated them onto a knucklehead engine which could be easily done. the engine was used in midget race cars built by drake. a custom bike builder jesse james found a drake engine and decided to build it into a custom motorcycle. drake had died but james went to his home and spoke to his son who was familiar with the engine. he gave jesse parts to complete and get the engine running. he had the drake mounted in a custom motorcycle frame but was having issues getting it to run. im not sure what happened at that point other than he said he would get it running. it appears there were many engines around the globe with designed versions of the v twin. and I would not be surprised if harley Davidson used designs for the Harley v twin from engines already designed and built somewhere in another country. that might be a secret we may never know. along side the indian v twin. I have always said the v twin was designed from the old 360 degree airplane rotary air cooled engines which were designed and used before v twin motorcycles were ever invented. I have already designed a new style jug that actually looks like the real jug but is liquid cooled. having worked in the boating industry and mechanically knowing how to exchange heat is all that is needed to design any air cooled engine to liquid cooled. even cooling an air cooled engine using simple copper tubing and a couple of other trade secrets. Harley currently uses jacketed heads with the exhaust ports being cooled which technically in not a liquid cooled engine. not even close. its a gimmick to keep the governments mouths shut and allowing the continuance of the manufacturing of air cooled engines in the usa. via the governments so called emission standards.

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