Ill-Advised Engine Swap of the Week: Aircraft Radial In Toyota MR2

Murilee Martin
by Murilee Martin
ill advised engine swap of the week aircraft radial in toyota mr2

The thing that got me hooked on LeMons racing was the mentality that makes a statement such as “Hey, I’d like to install a 540-cubic-inch, five-cylinder radial aircraft engine in the back of a Toyota MR2, then try to make it run all weekend in a grueling endurance race” seem totally sensible. The [s]craziest[/s] most devoted racers find themselves locked into an arms race for the Unununium, and this is the result.

The engine, which once powered a 1942 PT-22 Recruit trainer aircraft, was rated at 160 horsepower. This one hasn’t run for 65 years, but Radial Madman-In-Chief Marc assures us that it’s in good shape and should fire right up. As for the $500 limit, I exercised my authority as Chief Justice of the LeMons Supreme Court to issue a decree stating that radial engines shall be exempt from budgetary limits. You want a Pratt & Whitney R-2800 making 2,500+ horses in your Hillman Imp, and you can convince us that your hoopty-ass installation will be safe? Fine!

It’s going to sit in the back of the car, directly above a Subaru transaxle with a custom adapter flange. A V-drive, reduction gear set, and a much more reliability-enhancing gear is involved; you can follow the whole saga on this 24 Hours of LeMons Forums thread. Will it work? The real question should be: Will it have license plates?

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  • TheSlowLane TheSlowLane on Feb 17, 2011

    Big cylinder aircraft engines are meant to cruise at a constant speed, usually producing 70% TO power or less, so this thing is meant to be set at about 110HP and left there. Big air cooled engines also do not like to have the power changed suddenly. Quick power settings changes can cause thermal shock to big air cooled cylinders. Redline on this engine is 1850 RPM, why is a reduction gear being installed? So a maximum of what, 925 RPM(??) is going into the transaxle? BTW, Useable torque is probably from (let's be generous) 1000 RPM to redline. How many speeds will the transmission have to use this extremely wide power band? Engines of this vintage were meant to have a top oil for the valves. One solution is to mix about 25% 100LL with 75% auto fuel so there is some TEL for the valves. I'm sure the competitors will love breathing lead laced fumes. Radials are normally dry sump, so it will need an oil tank to hold, oh, three or four gallons of probably 100W aviation oil. 100W is about as thick as 50 weight auto oil, so perhaps straight 50 weight can be substituted. Radials are known as oil burners, but since this engine is "in good shape" maybe it will only burn five gallons or so in a 24h race, assuming it doesn't throw a piston through the head of a cylinder from excessive engine RPMs on the first lap. This could be interesting. Is anyone making a video? If it lasts half of a 24h race it should win a Unununium Medal.

    • See 5 previous
    • Mig29fuk Mig29fuk on Jun 06, 2012

      @Madman-In-Chief Just found the Kinner Radial as used in Toyota. Are you still using it? My Google search took me to you as I'm looking for the same engine for my Vintage Airplane. Know of anymore available. Regards Gerry

  • Phil K. Phil K. on Feb 18, 2011

    R-2800's are for nancy boys and Pirus drivers. Real men re-engine VW Type 2's with R-4360's, or Beetle / Dune buggy conversions with Dirty-Three fifties.

  • Allamericanred Interesting that as a car design nut that hates most American Suv designs that I think it is a pretty good design that stands apart but is not odd. The color really impacts how it looks to me. Some just do not work
  • NormSV650 I had a 2014 Vsport back in the day. It have a quiver feeling over some bumps in turns. Currently have a 2018 CT6 it is very solid and a great driver's car for the size.
  • NormSV650 I had a 2014 Vsport back in the day. It have a quiver feeling over some bumps in turns. Currently have a 2018 CT6 it is very solid and a great driver's car for the size.
  • MaintenanceCosts I saw my first IS500 out in the wild today (a dark-grey-on-black example) and it struck me that it was much more AMG-like than this product. (Great-looking and -sounding car.)
  • ToolGuy