My longtime friend Tom Jennings is a huge Rambler fan and walking, moist column of Rambler-knowledge, so when he encounters something Rambler-related he wasn’t aware of, you know it’ll be good. And boy is it: it seems, back in the 1960s, Rambler and Renault were developing—with an unclear level of seriousness—a deeply strange rotary engine that’s not a Wankel-style rotary. Just look at this thing.
The whole scoop was in the October 1964 issue of Mechanix Illustrated where it made the cover, relegating the new ‘65 Ford and Pontiac to little inset photos.
The cover illustration gives a good hint at the weirdness that lurks within, as the compact rotary engine unit is set transversely in that hypothetical future Rambler’s chassis, driving the front wheels and with a radiator set off to the side and also transverse, much like the setup in an original Mini.
The original article was written by Alex Walordy (I’m guessing, if we use Nintendo-name-logic, he must have been the evil counterpart to Alex Lordy) and very quickly makes clear that this engine, while a rotary, is not a Wankel-style rotary.
Where the Wankel uses a mostly triangular/hamantaschen-shaped rotor, the Rambler design—which was developed in partnership with Renault—used a four-lobed clover-shaped rotor set into a five-lobed, rounded-star shaped combustion chamber.
It’s a normal four-stroke Otto-cycle engine otherwise, with the lobes acting as pistons and the five “chambers” acting as cylinders.
Unlike a Wankel, which has its combustion/power stroke at one set point, this Rambler rotary could, with the addition of valves and spark plugs in each “chamber,” could have five points of power strokes, I guess sort of like five pistons in a reciprocating engine.
It’s really pretty different than a Wankel, which divides its cycles across the whole volume of the chamber, and closer to a piston engine, except without the need to convert reciprocating motion into rotary motion.
It’s certainly an interesting concept, though the same issues with sealing that plague Wankel engines would be problems as well, and the added complexity of five separate valve trains driven by some sort of planetary gear system likely made this a more expensive proposition than a similar reciprocating engine.
Compared to the then-standard Rambler inline-six engine, this rotary was incredibly short, and would have allowed for packaging solutions like transverse front or rear, or, if Rambler was really feeling saucy, a mid-engine solution. The idea of a rotary mid-engine Rambler American has almost too much joy for an ordinary human to bear, so perhaps they didn’t pursue it for humanitarian reasons.
There’s a picture of some sort of prototype engine in the article, so at least a test engine was built, but there’s no evidence, sadly, that AMC or Renault actually crammed one of these into a Rambler or Dauphine or anything like that.
This engine must have some fatal flaw—my guess is that it would simply be too expensive to make any sense, knowing Rambler, and that pretty effectively killed it.
I’ve tried to find out where the prototype engine ended up, but, sadly, it’s not unlikely it’s at the bottom of some Kenosha landfill.
This is pretty fascinating, but I suspect Rambler made the right decision not to pursue it. I just wish they’d stuck it into one car, at least.