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An OHC Hemi Engine in 1902?

This engine shown above, was made by Truscott Launch and engine works of Saint Jo-seph, Michigan. It was only briefly mentioned in the Truscott 1902 catalog as an experiment.  In 1906 Truscott began selling a marine engine that was identical to the 1905 Welch four cylinder. They also sold engines of their own design. In addition to the OHC, note the fully counter-balanced crankshaft.

Reader Don Curtis has a Truscott engine which is very similar to the engine pictured above and lead us to some of these illustrations and information. He hopes that someone can find more information on this whole story. The later Welch engine had several im-provements over this engine. In addition to boats and marines engines Truscott also made engines and hardware for several early automakers. It appears that these two companies, even though they were one hundred and twenty miles apart in Michigan worked together. Welch at the time was located in Chelsea, which is much closer to Detroit. Perhaps they worked with Truscott because of their casting abilities?

We question who came out with the original idea, Truscott or the Welches, whose patent drawings filed in 1905 are shown. The ad for the Truscott foundry below, was from Gas Power 1908 and states that the foundry had been in operation ten years. With quite a bit of searching we were also able to find illustrations and text in the Automobile Review, March of 1903, and the Automobile, Feb. 1903 showing the new Welch touring car and showing three overhead valves in a “spherical combustion chamber” The text from The Automobile states ” The inverted valves in the center of the heads and mechanically operated by cams on a rotating disc between the cylinder heads turned by a worm gear in the crankcase on the lower end of a rod passing down between the cylinders.”

From all of this information we can be reasonably safe assuming the Welch built this car in 1902 to get it ready for the 1903 Chicago Motor Show held in February. What we have found in this latest information seems to document and may predate the recognized 1904 dating of Welches first OHC hemi. Read more in the comments on the last post in this earlier Matheson information.

Can any readers add more to this story or show us evidence of an earlier OHC engine here in the states? Who can tell us about the early OHC engine designs from other countries?

14 responses to “An OHC Hemi Engine in 1902?

  1. I guessing the crankcase stays open? or would it have a sheetmetal cover? Would love to see this engine run, there’s a lot going on there.

  2. David,

    Great stuff. The firmness of the dates gets very mushy before 1905. The Welsh looks very similar to George Weidley’s 1905 Premier, which is well dated and documented. The Welsh has straight rockers instead of forked, a wider VIA, water cooled, and less attractive porting, but was a road car engine. All of the Welsh engines I’ve seen were +1907, do any pre 1905 examples exist ? Weidley produced more innovative OHC engines, with unique features, Welsh did not, but I believe he died in 1913. An OHC hemi head was hardly needed on a 1905 road car bottom end. Could Welsh have seen the “one off” race car Premier and adopted its features for his road car after 1905 ?

    In Europe, Han Ledwinka, the man who invented everything that makes a Porsche a Porsche, supposedly designed a 3.3 liter SOHC hemi engine in 1905, but it did not reach production until 1909. Mercedes Benz built a SOHC race car in 1906 with a very modern design, but it was not raced because of an internal dispute between Maybach and Daimler. MB also made SOHC airship and airplane engines after 1906.


  3. David,

    The earlier Welsh engine has three vertical valves and is not a hemi. If the patent for the OHC , inclined valve, hemi was filed in May 1905, it appears to predate the first race appearance of the Premier in November 1905, but I’m sure Carl Fisher was hyping the design well before it appeared….


  4. David,

    The description is incorrect, a hemi engine by definition cannot have inline valves. Three inline valves sounds like a bathtub to me. The European claim for the first hemi is the Belgian Pipe, but the date is confused and cited as 1900, late 1904 or 1905. In any event it was a pushrod engine and Weidley’s Premier appears to be the first OHC hemi to be actually raced.


    • Paul , Yes it is not like the normal hemi with a valve on either side of the combustion chamber. If you study the text and the illustration there are (3) valves and two appear to be inline (the intakes must be side by side). I looks as only the exhaust valve at the top was driven by the cam, the intakes on the right hand side at a 45 degree angle appear to possibly be atmospheric valves??

      What ever we call it it is very remarkable to be made in late 1902-03.

      • David,

        I read the description as three valves, 2 intake and one exhaust, inline in the center of the chamber. Some arithmetic, 1.25+1.25+1.75+ seat width= no room for a hemi chamber. Not sure what that thing is on the side of the drawing, spark plug ? I agree it is interesting and unique and shows Welsh knew the relationship between intake and exhaust sizing better than most contemporaries. It is almost a square bore and stroke , another big plus, and only a step away from the oversquare 1905 Premier. The cam gear sounds different than the Truscott, the Truscott looks like it has a camshaft and the Welsh description is a rotating disc which I can’t see in the diagram. I can’t see how those valves are operated can you ? OK, how’s this WEideley and Welsh went to a picnic sometime after the first Welsh design, they went for a ride in a Truscott powered boat. They both copied the valve gear, but AR could not remember the forked rocker because of the pretty girl sitting between them ?

        • Paul,
          I guess we may never know exactly what that description means because as I can read it both ways. I have blown up the illustration here and the device on a 45 degree angle sure looks like a poppet valve (the scale of which looks correct given the valve dimensions) with what appears to be a small spring in the middle which is why I mentioned that maybe the intakes were atmospheric valves on the side. The dome over it may be a cross section of an intake manifold?

          It is listed as having jump spark ignition but what is on the side does not look anything like a spark plug. Jump spark can also be used with the make and break system which may have been as we see in the Truscott ??

          The writer description sounds like a vertical shaft and at least a gear in the crankcase, maybe by the disc at the top he meant gear? The writer also says the valves in the center are mechanically operated by the cams. My take on all of this is that the writer did not get his description across very well which is normal with early magazine reporting.

          As to the valve gear I think the writer was trying to describe the vertical shaft and gearing.

          Hopefully someone may have more information or a photo so that we can get a better idea of exactly how this engine was constructed.

          I will keep looking to see if I can find anything more in periodicals of the time.

  5. David,

    Ludvigsen describes the first Welch engine as two automatic intake valves on top and a pushrod side exhaust valve. Not a “disc” OHC and more inline with the drawing than the newspaper account. I can’t imagine why Welch would play around with this inferior design if AR had already designed a SOHC, inclined valve, hemi with rockers, earlier for Truscott. There are photos of surviving Truscott engines online and they show a front cam drive like the later Welch, not a center cam drive. If AR Welch, a man, did design the Truscott boat engine, there is another interesting OHC marine angle. Boris Loutzky supposedly designed an OHC single in 1896 that set world speed records. There is a good chance that a boat mfg like Truscott would be aware of a speed record design. Loutzky then had MB build him an OHC marine engine in 1903, which may be MB’s first OHC engine and where Maybach got the idea for his 1906 racer that Daimler did not like (until Maybach was forced out). It had a vertical intake valve and offset exhaust valve with a OHC offset to the side. Very much like the Matheson. The road may lead to Boris, friend of the Czar and Kaiser. The Truscott engine may be based on the world record Loutzky marine engine and the Matheson a copy of the 1903 MB Loutzky…..


    • Paul,
      It would be interesting to read the source of Ludvigsen’s description is clearly different the description from the 1903 Automobile Magazine in the last thumbnail in the post. Karl occasionally checks in here and maybe he will mention the source where he found it. I have looked at the photos of Truscott engines online also and it appears they were made both with a shaft inside as shown in the catalog illustrations early on and also at the side as the photos show later.

      My take on all of this is that this may have been, Welch’s first step to OHC and only used it for the exhausts in the center even though we cannot see it all in the drawing and the two side valves were automatic or atmospheric.

      I also found in the Horseless Age from 1903 a description as follows: The ignition is by jump spark type and the current is supplied by batteries. A single coil without vibrator is used for both cylinders, the primary make in break being fitted with heavy platinum points and protected from oil and dirt. This leads to the Welch having a make and break ignitor are can be seen in two of the Truescott illustrations above and not a spark plug.

      I am afraid without a clear photo or drawing of the 1903 Welch engine we will never be able to know for sure. Hopefully with the reach of the internet someone out there may have the information or photos? Do any of our readers have an illustrated 1903 Welch sales catalog?

  6. In terms of the origin of the hemi engine, inventor, Augustus M. Herring experimented with the hemi while he worked at Truscott’s Boat Manufacturing Co., in St. Joseph, Michigan in 1898. I have much more if anyone is interested.

    • David Gierke: I am very interested in what you know about the original source of the Truescott hemi engine, and this Augustus Herring. Please leave a reply here.

  7. two cylinder over head valves and hemical combustion chambers and put out 20 hps, Chelsea Mfg. co. product from 1903 to 1909 in Chelsea Michigan by Welch before G. M. bought them in late 1909 and made it Pontiac after Welch got in money troubles and moved plant to Pontiac Michigan

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