Rusty_OToole

T head engines who used them?

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Around the WW1 era a number of quality cars used T head engines. Pierce Arrow, McFarlan, and Stutz had them. The subject was suggested by Jay Leno's recent show about a 1918 Stutz Bearcat. I was wondering what other cars used the T head especially with 4 valves per cylinder.

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Slightly off topic but I think one of the last 'vehicles' to use a T head engine was the Gravely garden tractor   -   a 1930s design that remained in production through to the 1970s with parts still readily available   -   7_6_L_Engine.png

Edited by nzcarnerd (see edit history)
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The most famous would be the T head Mercer of circa 1910 to 1914.  Many others on both sides of the pond built T heads.  The 1908 Austin 100hp grand prix car had a T head six of which four were built. Austin's production cars of the era were also T head.

 

The T head Simplex influenced the design of the American LaFrance four and six cylinder fire trucks which remained in production through to the mid 1920s (or later??).

 

There were also many commercial (truck) and marine and stationary T heads.  I think the list will be quite extensive.

 

As to who built the first T head, I don't know. From what I have seen of the more common pioneer one and two cylinder American cars - Olds, Cadillac, Ford, Northern  etc - most used side by side valves.

 

I don't know of any others that had four valves.  I think that by the time Stutz came up with their 16 valve unit most other manufacturers had gone to L head or ohv.

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Hi , Rusty , early Peerless used some very large T-heads. Man with all the cars made in the early low compression days , it will be interesting to see how big this list grows to.  - Carl

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It would be a very long list, many early makes used T- head engines.  4 valve per cylinder T - heads are much rarer .

 

 My Staver Chicago uses a Teetor Hartley 2 valve T head.  Also used by American on some of the Underslungs and Pilot.  Still looking for Teetor parts , crankcase, camshafts , Etc.

 

Greg in Canada

Edited by 1912Staver (see edit history)

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Seagrave also used a 1000+ ci T-head in their fire trucks. The first time you see one in person it will leave you speechless :)

 

 

 

 

 

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Loziers used T head motors through 1913, Model 72.  They did use an L head in a less expensive model in 1909-10, the Model J.  In late 1913 they introduced the L head again in the model 77.

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I'm especially interested in 4 valve per cylinder or dual valve type. It seems they were used by some very expensive, well regarded vehicles like Stutz, Mercer, Lozier, Pierce etc. so they must have had some advantages.

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Mercer T-Heads were only in Model years 1911-1914 and were all two valves per cylinder.  Valves were 21/4 inches in diameter in a relatively small engine of only 300 cu. in.  I believe Stutz used a much bigger Continental engine but with the standard two valves per cylinder. Perhaps Ivan Saxton or some other Stutz experts can comment further.

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The subject came to mind because of this video of Jay Leno's 1918 Stutz Bearcat with its 4 cylinder, 16 valve engine.

He says this engine was new for 1918. Why would an expensive car come out with a new 4 cylinder T head when everyone else was making 6s and V8s? Well some experts considered the big 4 cylinder the best for performance. And the T head dual valve was the best way to get good breathing with simplicity and reliability. The large combustion chamber was not much of a drawback, the available fuels only permitted low compression anyway.

 

So this seemingly retro engine had a lot to recommend it. This made me wonder what other cars followed a similar line of thought. I know a few did, but this line of development soon came to an end after the introduction of the Ricardo head in 1921 or 22.

 

Stutz actually had an overhead cam, hemi head 4 cylinder with 4 valves per cylinder before the big T head, and also made six cylinder cars with engines of similar size and power for those who preferred the smoother engine. So they must have thought a lot of this type of engine , not knowing it would soon be obsolete.

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My apologies, I did not realize that the Leno car was a T-Head. The 6" stroke seems a bit unusual for an engine designed by someone like Harry Stutz who built racing engines.  

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That is kind of the point. He was building a performance car to sell to the public for regular road use, he could have used any kind of engine and he chose to build a 4 valve T head 4 cylinder. This seemed like an unusual choice yet I vaguely remember other high quality performance cars of the time that used similar engines. So I was trying to figure out why.

Edited by Rusty_OToole (see edit history)

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First, Mercer did not use 4 valves per cylinder, the T head have 2 valves as stated and the L head of course also have 2.

Second, Stutz started with a Wisconsin built T head of 2 valves per cylinder in 1912. The Stutz White Squadron racing team of 1915 did have single overhead cam 4 valve also built by Wisconsin.

Third, With the gasoline and technology of the time, a 4 valve per cylinder 4 cylinder engine was not a non-competitive passenger car engine to introduce in 1917. There were some V-8 and V-12 engine but they were much more expensive, not terribly superior, so 4 and 6 cylinder still ruled the day and continued to thru the 1920s.

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I can give you a few more, even without consulting my books.  And I can clarify for you why some were not beastly huge and inefficient;  and that was not just, (as one other very expensive English car was described), as "the triumph of workmanship over design".    I had one 4 cylinder T-head engine that was very small. I never measured the piston displacement when I saved it from a junk yard in 1962, because even then I perceived that you did not improve the survival prospects if you dismantled an engine without immediate purpose or prospect of restoring it.  Eventually we identified that it was a proprietry  White and Poppe engine, that could have been used in a number of small English light cars around or before 1914.  But it was most likely from an early "Bull-nose"  Morris. It may have been around one litre displacement.  I passed it on to a man who had one restored.  Another Engine I recovered was a much larger 2 cylinder.  I was told it was thought to be a De Dion, but it turned out to be  an Albion, always more renowned for building trucks and buses, though it was from one of their cars.  A friend in Sydney recommended that a person north of their deserved it .  Someone else collected it, but there was never a message of gratitude.  The interesting feature was that the sparks were initiated in the cylinders bye points inside each cylinder that were  opened mechanically from outside for Low voltage ignition. The vehicle was a fair size, but it was a slow moving roadblock on the 1970 FIVA International Rally from Sydney to Melbourne; but I was surprised that the owner was not interested in showing me the car or discussing it.   The early Mercedes Simplex cars of renown and impatience were T-head.  The drive system could be either tailshaft and bevel gear, or chain drive. A moderate size shaft driven example  was on display at Auotoclassica in Melbourne last weekend.  It had survived on a big sheep station in outback Queensland.  You will be familiar, I hope, with that extraordinary photo of Ralph De Palma and his mechanic, Rupert Jeffkins from Sydney walking back to finish the second last lap of the 1912 Indianapolis 500, pushing their Mercedes Simplex which coughed a connecting rod and lost all its oil. It is midnight now, and I will continue tomorrow with fewer typographical errors to correct.

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Maurice Hendry reported this. W O Bentley was a fan of Cadillac cars and the work of Henry Leland in general. One day he asked Leland why he made a V8 when he could get the same power from a big 4 cylinder. Leland replied 'Mr Bentley you are a man after my own heart. But you are overlooking the fact that I can sell an eight cylinder car, where I wouldn't be able to sell a four'. I think this must have referred to the 1915 - 1922 models that had a 4 cylinder type crankshaft and a secondary vibration to match.

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The Peugeot Bebe engine was an Ettore Bugatti designed T head of only about 850 cc   -    SetWidth900-LF3-6629.jpg

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The Teetor Hartley in the later McFarlans had 4 valves/cylinder, and also three spark plugs per cylinder.   Stearns made fine big 4 and 6 cylinder T head cars, before they regressed to Knight sleeve valve engines.  Ralph Stein's account of the performance of a big Six from Harrah's, to and from his chosen site for a photo shoot  for one of his books is most impressive. You need to recognise Marmon, winner of the first Indianapolis 500,  Thomas which won the New York - Paris race, and Prince Scipione Borghesi's big Itala which won the Peking - Paris race the year before.    Most of Locomobile's most expensive cars were T-head, (though the winner of the Vanderbilt looks to have overhead inlet valves in a picture I have seen.)  Packard made T-heads from 1906, including  S, Thirty, Eighteen, and the largest Six,  (which changed from T head to L head just before  the introduction of the Twin Six.  The two smaller Pierce Arrow sixes were changed to dual valve about 1919.  You could imagine that the big single valves could have had a problem to keep cool , shedding heat via their stems and faces;  before better materials (like cobalt) improved hot-hardness and high temperature oxidation.   ( I will share a trick I worked out.  I wanted to stellite the faces of 1911 Napier valves to re-use them, but they oxidised badly, well below the pre-heat needed to wash on the cobalt re-facing.  So I sprayed on a protective coating of nickel powder from an oxyacetylene "hopper-gun", and then I was able to wet and build up the faces with stellite filler rod.)    Humber, Hillman-Coatalen, and Sunbeam all made T head cars, after the time that Louis Coatalen moved to Coventry in England and worked for those companies.  ( Actually, Humber had two separate factories , in Beeston, and Coventry, which produced cars which differed  in some aspects of style in their design.  Certainly there were T heads made in Beeston.  The smallest Sunbeam model, the 12/16, was a 4 cylinder 2.4 litre displacement T head;  but the model was given a new L head engine of three litres displacement during 1911,  with the same bore size and an increase in stroke length of 25% for 3 litre displacement.  Sunbeams were racing those in excess of 90 miles per hour in 1912 and 1913; and in the Coupe de l'Auto  run concurrently with the French Grande Prix, three Sunbeams placed 1-2-3 in the main race, not much slower than the first winning race time of the first Twin Overhead camshaft Peugeot, which was more than twice the engine displacement of the little Sunbeams ! To quickly end this deviation from tropic, which is specifically for Allan, whose family have owned his T head Mercer Raceabout for many decades,  the Sunbeam could have been the inspiration( metaphorically) for the engine of the Delthal, which was the prototype for the L head Mercer.  The Sunbeam was 60% of the piston displacement of the Mercer, with some similarities in design, including identical proportions of bore and stroke, which I understand is considered to be a key design index.  There is also a similar proportion to piston stroke to connecting rod length:  Variation of that varies piston acceleration and maximum piston velocity.  I have examples of both cars.  Piston Stroke of L head Mercer is six and three quarters inches, which is a bit longer that the Stutz four.

Probably the most significant T head engine of all was an Isotta Fraschini. The first designer, who was more a consultant than an employee,  was Giuseppe Stefanini.   He produced prior art to Mercedes fabricated sheet metal water jackets on their WW1 aero engines on T head cars  with separate cylinders as early as 1903.  He was subsequently designer of some lower end production models, but also two overhead camshaft cars.  The 1905 TipoD 100hp "Grand Prix"  car weighed less than 200 lb, and had an oversquare 4 cylinder 17 litre displacement engine with 185mm bore and 160mm stroke.  The other was a jewell of a small car , the Tipo FE 1200cc for voiturette racing, and the 1300cc version as a production road car.  Giustino Cattaneo designed a T head for the required formula of the 1907 Kaiserpreis, and also used for the 1907 Coppa Florio.  Minoia won the Coppa Florio,  at 64.94 miles per hour, using just 19.8 Imperial gallons of fuel for 302 miles.  This was economy of 15 miles per gallon at full throttle of an 8 litre four cylinder T head !!!!!      The understanding of this is from the technical section of Angelo Tito Anselmi's book on Isotta Fraschini, on page 228.  There is  a longitudinal longitudinal section engineering drawing of the engine.  The highly domed piston crown almost touches and matches the combustion chamber roof. There is twin ignition with sets of spark plugs on both sides of the engine, from a twin-spark Bosch magneto.   The twin spark magneto has the two live ends of the high voltage coil winding connected to opposite segments on the slip-ring where the pick-up brushes run.  So the spark is synchronised on opposite sides of the combustion chamber (or chambers).   What Cattaneo did was unwittingly create "prior art" to Sir Harry Rickardo's 1917 L-head high compression  "Turbulence" combustion chamber patent.  There was very high compression ratio for efficiency and economy,  short flame travel (which is timed in milli- or micro-seconds; and the residual charge between the piston crown is chilled by divining the cooling water and cooling oil so that it is unlikely or impossible that it can absorb enough heat from the flame fronts to explode and cause knock.   The potential power output of an engine is limited by its proclivity to knock,  and that is affected by chemical composition of the fuel, presence of additives, and combustion chamber deign, in particular, squish and turbulence.   After the 1907 Coppa Florio Isotta Imports contracted Isotta Fraschini  to build and supply a team of identical cars, which Al Poole, Hugh Harding, and Lewis Strang raced so successfully in 1908.  Two of those still exist, one in USA and one somewhere in a Japanese museum.  Engine bore and stroke is 145.4mm x120mm.   By contrast the 1908 Tipo Targa Florio cars were similar but different.               Bore and stroke were 130x150mm for almost the same displacement.  But without twin ignition in a T head, and without that squish area and high compression ratio, you could not expect the cars to go as well.

Ralph Buckley told me in 1980 that the piston crowns in the later T head Mercer Raceabouts nearly hit the chamber roof and had high compression ratio.  So if you slowed down you had to change down;  or you risked breaking the hold-down lugs on the cylinder blocks.

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If you can't have a T head MERCER, there is nothing wrong with a 6 cylinder ALCO. Bob Image result for alco black beast

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The t-heads could contain really large valves and could breath better.  Better thermodynamics allowed  the L-heads to breath just as well in later years.  Just look at the valve area on a four valve McFarlan.

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Do you mind telling me the make of the 6 cylinder T head .   There are no obvious clues to its origin, unless you have seen one before.    I cannot answer Rusty's last question, because what works well or not is probably dependant on design variations.  Certainly Cattaneo's Briarcliff Trophy / Coppa Florio Isotta Fraschinis were extraordinarily fast and economical because of the "squish area" and very high compression ratio.  The short stroke relative to piston diameter must have usefully extended the rpm range,  And I suspect that Finley Robertson Porter may have seen inside  one of those Isottas, and copied it for the later T head Mercer Raceabouts.   You should find and read a copy of Griffith Borgeson's book on the " Classic Twin Cam Engine".  I personally disagree with his obsession that the T head developed into the Twin OHC;  and his belief that the valves at an angle to the cylinder axis gave an advantage in efficiency  for the L head Sunbeams and Packards.     I forgot to mention the 80mm bore x 180mm stroke 4 cylinder Alphonso Hispano Suiza.  They would really shift the scenery.    I found a photo  of the Albion 2 cylinder T head engine that I picked up in about 1964.  It must be one of the weakest  T head engines ever built.   My son is going to digitise the Photo, and I would be grateful if someone could post I on this forum.   

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Here is another odd T head engine.  I had forgotten about this one that I took these pics of in England recently - I saw so much that some days are still a blur. These were shot at the Museum of Lincolnshire Life in Lincoln. The only info is what you can read on the sign in the first picture. Whether the national is the well known manufacturer from Indianapolis USA, or someone else I don't know.

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