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Hagerty Employee

5 of the strangest engines that made it to production

An engine puts the auto in automobile; without one, you merely have a carriage and have successfully shifted yourself backwards by 120 years. A century-plus of engine development has brought forth a vast array of solutions to the internal combustion problem. Virtually every person who has set their mind to building a car has experimented with the number, orientation, and even shape of the cylinders.


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Don't forget the TWN (and others) Twingle 2-stroke single cylinder engine with 2 pistons on a single connecting rod.  Surprisingly very reliable.  

Intermediate Driver

Or the Willys knight sleeve valve engine. 

Cylinder liners with slots in them move up and down to create  the intake/exhaust valves. 

Look it up for a better description. 

New Driver

Cadillac was building a 16 cylinder engine in the 30's -- many of them still running strong.


Not just Cadillac. The Marmon V16's were marvelous engines.

Pit Crew

It's not an usual engine to look at...but the 70s GM 350-V8 diesel was a shot at a fuel sipping torquey car and pickup power plant...a "beefed up" Oldsmobile gas V8 block retrofitted with diesel was a valiant effort but the result was less than leaked oil like the Exxon Valdez due to inadequate crankcase ventilation, it was necessary to carry extra fuel injectors so you could do your own replacements when convenient, double stacking the air filters helped some with doused the house garage with oil and diesel fuel odors  which required parking outside to keep the wife from grumbling about her home smelling like a truck stop...owning one of these sharpened your shade tree mechanical skills...I loved that diesel wagon in spite of it's shortcomings...


It's a often repeated myth that it's a beefed up gas engine, it's not. It was a clean sheet design, though it shared bore centers and stroke so it could easily be built on the same tooling, and shared bellhousing, mounts etc. so it could easily be integrated in to the same cars. When you have the two blocks side by side on engine stands though, it's obvious the much beefier diesel block did not start as the gas powered Olds 350.


Two of the biggest problems were owners unfamiliar with diesel and poor quality fuel. There were some engineering issues as well, but by the time they were discontinued in '85, they had a lot of the kinks worked out. By that time though, nobody would have one.

Pit Crew

Neat read, luckily the oval Honda was listed last, my ADD kicked in and I haven’t been able to stop thinking about how many piston rings I would break rebuilding that engine.

Intermediate Driver

Great though provoking article. Seeing as a Honda motorcycle engine was added, how about the Honda RC116 50cc twin engine with possibly the best BHP per litre figures ever. Or the Honda RC166 250cc 6 cylinder engine !!

For all you engine addicts check out the Jimmy Deville Engine Addict TV programme. Its a UK production but may be available internationally.


Maybe not the weirdest engine on the planet but by far, one of the nicest looking works of art I remember is the inline six in a 1968 Maserati Mistral. With dual plugs per cylinder and updraft carbs, it's a beauty.

Pit Crew

No early steamers?  They were functional automobiles, especially the Doble (SP?), although they were expensive and rare.  But there were plenty of Stanleys.

Intermediate Driver

Interesting articles & a great Jay Leno video about the Chrysler turbine. I got my first job at the Social Security Administration Headquarters in Woodlawn Maryland in 1965 & there were one of these that could occasionally be seen parked in front of the Headquarters Administration building.  I heard that one of the higher level government executives was provided one of these turbine cars as a test vehicle, otherwise I might have never known at that time that these turbine cars even existed.


I think Jay Leno, like Johnny Carson before him, was a great ambassador for clean comedic entertainment.  So unlike many of the crude comedians of today who used foul mouthed 4 letter shock comedy to establish notoriety, which has now become so utterly boring!     

Intermediate Driver

My grandfather owned a gas station in Los Altos, CA at the time. I remember one pulled up, and I was asked to find the dip stick for the oil! As it used hydraulic oi, it shared with the transmission as I remembered. I was 11 at the time!

New Driver

You are right on.

Pit Crew

When I was 13 in 1965 delivering Sunday papers I saw a turbine car at a local restaurant, I knew what it was after seeing one in Hot Rod Magazine.
This was in a small river town in WVA which made it all the more rare at the time in our little town, it was the turbine bronze color, I told my dad who was a mechanic who said it would run on anything combustible.
I saw a Leno interview recently & he said they took one to Paris France & had it run on Chanel number 5. lol
New Driver

You missed my favorite -the Adams Farwell.  It was a 5 cylinder , air cooled, rotary (the entire engine rotated)It had no flywheel as the engine was its own flywheel.  The rotation also aided the air cooling.  As I recall, it also required no valve springs as the centrifugal force closed the valves. The car itself was also unusual, with a 4 speed transmission and a movable steering column that allowed driving from the right, left, or center - the US hadn't settled on which side of the road we would we drive on.


There was a 3 cylinder as well as a 5 cylinder version of the radial rotary Adam Farwell


I'm impressed that several commenters on here know about the Adams Farwell. It's a fascinating car. You can see & hear one running on YouTube here:
32hotrod, you sound like you know your stuff, as do you too, FM.

Have you seen the Napier Deltic diesel? Comparatively light, powerful and beautifully complex.


More non- 4 cycle reciprocating piston examples would have been interesting. I have also seen examples of aircraft radial engines used for motorcycles. Not sure if they ever made it to a car


The Tucker used a Franklin aircooled radial, which I believe was used in early post-war helicopters.


Tucker used a Franklin air cooled helicopter engine, but it was a flat six, not a radial.

Wrong again. They tried to use a flat six air cooled Franklin and couldn't make it work until they produced a water cooled flat six that was never used in any aircraft. Under Tuckers ownership Franklin died.
Pit Crew

BRM F1 engine fron the 1960s 3 liter era.  H-16 configuration.  Wonderful sound, 2000 more RPM than the V-12s of the competition.  Too bad the oil wanted out so badly.


Knight sleeve valve engine, a Actual production engine

Pit Crew

At least one did, but my memory of it is vague, and I think it was a race car.


How did they leave out the scotch yoke engine?  That is an extreme variation. 

Intermediate Driver

Love the combustion turbine engine. Not as loud as I would have guessed, but a great sound. That interior is spectacular.  The regenerator reminds me of an air heater in a coal plant. I'll bet maintenance would have been pretty costly. 

New Driver

The Crosley "CoBra"  (CopperBrazed) 4 cyl, 750cc, OHC, sheet metal, VERY lightweight, no head gasket, CHEAP,...


How about a sleeve valve?


I am not aware that these ever were made for over-the-road vehicles but the Fairbanks-Morse opposed piston 2-stroke diesel was quite successful a marine power plant, particularly in submarines and smaller ships.  It was less successful as a locomotive powerplant, however, even though they developed more power than competing models at the time.


I drove a Turbine! I was a Freshman (or maybe Sophomore) at Boston University when Chrysler brought one there, I guess just for comments from young people, since I was not in engineering classes or anything else directly related to automotive development. However, I was an avid gearhead, which the professor who was given the task of picking some students to drive the car knew, and he chose me as one of them. When the day arrived the car was parked by one of the ramps from campus to Storrow Drive, and I drove it from there to Copley Square, where I turned it over to another student who drove it back, where another two took it over. I remember being totally impressed with the quiet whine of the engine, and the heat and volume of the exhaust. I was also very disappointed in the performance- a Batmobile it was not!

Intermediate Driver

If you are including motorcycles then the Ducati desmodronic 900 was a great engine. If you are including all engines then there is nothing like the Napier Saber H24 aircraft engine. Two flat 12's geared to a propeller drive with sleeve valves, and supercharged. Probably the most powerful gas engine ever build, with the exception of the experimental Lycoming XR7755 radial that produced 5000 HP.

Advanced Driver

I would add the Willys Sleeve Valve engine and the rotating block engine that powered all 52 Adams-Farwell cars built from 1901 to 1913. And I see, 32hotrod mentioned the almost forgotten Adams-Farwell engine as well. 


That engine was designed like a then contemporary aircraft "rotary" engine. Most WWI Allied aircraft were powered by "rotaries", and a few German (like the Fokker Triplane). There is a LOT of torque in one direction due to a heavy cast iron block rotating! Plane could snap roll in one direction, would be sluggish (in comaprison) in the other. Blip the throttle to hard and fast and ground roll one of those powered kites! Take-off and landing could be tricky. I can't imagine one in a car!! Some models of the Sherman tank used them, and there is one in a truck built recently ( You can see the packaging problems! The Adams-Farwell was much smaller in diameter and packaged flat -- the crank was vertical instead of horizontal. That helpd, and prevented the roll-over torque. Couldn't have used an aero engine!
Intermediate Driver

I believe you may be confusing the rotary engine with the radial engine. As you stated, the early WW1 rotary engines had a fixed crankshaft and the block and cylinders spun to facilitate cooling. The radial has a fixed block and cylinders and the crankshaft does the rotating. The M4 Shermans used a version of the Wright radial engine produced by Continental. There are a couple of good articles on radials and rotary engines in Moto/ology Magazine. see it here:

Rotary can also mean Wankel just to add to the confusion...But there's video on YouTube somewhere (I couldn't find it just now, can't recall the brand - 1920's era? Someone here will know) of a rear engine rotary starting and running. So bizarre seeing the cylinders whipping around underneath the car!
Intermediate Driver

In the 1920's Packard experimented with a straight-twelve road car engine.


In 1953, before he left Ferrari, Aurelio Lampredi designed an inline two-cylinder 2.5 liter grand prix engine, the type 116.  At least one engine was built, but it never went into a car.  The engine still exists.


Intermediate Driver

The V-16 rear mounted engine in the Auto Union C-Type was pretty amazing and successful.


The Chrysler turbine was uneconomical because we could not get a hot pressed ceramic wheel to work. Machined wheels were expensive. The '63 turbine car, shown at the New York World's Fair Chrysler exhibit, was a little faster than a 300hp Impala on Woodward that year. The EPA was measuring outlet air that was only 1/5 engine exhaust, the rest bypass cooling. They were counting ambient air in their analyzer and would not run a second parallel air test to check ambient alone, hence failed test. We had a running discussion with them, even on our regular engines, by showing ambient pollution levels and asking that  they be deducted from total exhaust. Last turbine was in a '76 B body that I helped work on.


Engine testing always seem to start in the Motorcycle 'Race' Tech.

Start small, Develop, fine tune, "Race the Development to its limits".

Push that Tech. to F1 racing

Honda is the best example of this process,

"17,000 rpm Oval Piston in the 1990's.

Pit Crew

The Knight-Stearns sliding sleeve motor should be on the list. 


You don't have to go too far back to find unusual. We're all now familiar with the smart fortwo but what many Americans may not realize is that there was a version with a 3 cylinder turbo diesel. It was a 0.8 liter. You could get them in Canada only during the first two years of importation and infact it was the only engine available. By clipping the speed limiter, upwards of 170 kph was possible and some owners achieved more than 100 mpg. I bought two of them new back then.


New Driver

Good choices. I think the Knight engine that had sleeve valves was an early engineering marvel. Powered cars like the Willys-Knight and was licensed to a fair number of other companies including many European cars.


I saw the Chrysler Turbine Show Care on display at the local Wheaton (Maryland) Plaza Shopping Mall back when Chrysler was sending the car around the country on tour. I was 11 or 12 years old at the time and it was cool then as it is now!  If I remember correctly the turbine could run on just about any combustible liquid including Vodka!

Intermediate Driver

The Wankel engine was closer related to NSU, they used it in their 1964-1967 Spider and I belief also in the coupe version. It was later used in the RO80 which was a very nice looking car for it's day but not very reliable engine wise, the amount of warranty claims killed the company and at that time Mazda bought the rights to build the engine.


in the early 1950s I worked on aV4  ( Icleaned the Parts for my journeyman)   that was a 2 cycle engine that had an additional  2 cylinders  that pushed the mixture int o the engine cylinders   it mght have been a Horch or some other Auto Union Vehicle


Surprised Hagerty of all places  would ALSO be clueless about rotaries. Thanks for keeping our parts prices low!

New Driver

I kinda expected to see the sleeve valve engine here.  Willys Knight had one in production a hundred years ago.

Pit Crew

The Franklin engine used in the Tucker was not a Radial but an Opposed 6 cylinder, very much like a Corvair or Porsche engine. It was based a on Aircraft & Helicopter engine though.


How about the Sleeve Valve Knight engines? I always thought they made a very smooth running engine compared to the others of the era.