2,775 cc Piston, rod and cylinder sets


We now have complete 2,775 cc piston, connecting rod and cylinder kits on the shelf. These kits complete everything from both Groups 1300 and 1400, including copper base and head gaskets. You can read more on the development of the 2,775 forged piston here: 2,775 cc Pistons are here. and you can also read about the flexibility of fuels they allow here: Compression Ratios, Fuels and Power Output.


These kits are very complete, and Feature new Weseman billet connecting rods with ARP bots, which are far easier to install than stock rods. These rods also feature fully floating wrist pins running in precision honed bronze bushings. Both the head and base gaskets are copper, and do not require any sealant. The Cylinders for these kits are bored for us by Clark’s Corvairs, to a 220 finish on their machines set up to exclusively do Corvair cylinders. The pistons are forged in California, made to the finest standards by the same company that has made all the 3,000 cc and 2,850 pistons.  The piston rings are included, they are Hastings chrome rings, the same ones we have used in countless Corvairs over the years. They break in easily in an hours ground run. I have never seen a single ‘glazed’ cylinder from their use.


Here is the direct link to the Kit:





Above, a 2,775 cc Forged piston made in the USA. The custom shape of the dish in the head works with the Corvairs combustion chamber to allow a wide variety of fuels to be used without adjustment.





6 Replies to “2,775 cc Piston, rod and cylinder sets”

  1. William,
    Really enjoy reading your penned thoughts. Gives so much insight into who you are and what shaped lessons of life shaped you into the person you are today. Great stuff as far as the educational value and amount of knowledge gained in the area of aviation and life. A friend and I started a 601XL last September and we had ordered a 2850 kit back at CC34. We are trying to decide if we need to make the switch to the 2775 that you posted today. Really had heart set on the 2850. Could you drop me an e-mail with the possibility of the 2850 as our wings are on and we are running control cables. Thanks for what you do to make flying affordable for the common person.

    1. Rick,

      If you are making good progress and don’t wish to have a delay, I suggest switching you order from 2,850 to 2,775, which we will gladly do for you.


  2. I live at over 5000 feet and had my heart set on the 2850 for maximum displacement and the future turbo option. (Or electric clutch Supercharger, or nitrous, and or water injection or whatever genius method you develop.) Is that 2850 option now unavailable, and is the 2775 suited for those altitude offsetting options?

    1. Howard,
      I try to move all the new 2850 people to 2775’s for one main reason, the 2850’s sole source for the Cylinder was Clark’s ‘full fin’ HD unit, and it became so costly and hard to get that I actually lost money on the last 10 2850 kits I sold. The 2775 doesn’t have this Issue because it uses a standard Corvair cylinder, of which I have 300 in my hangar, and nearly 200 more already at Clark’s. A side benefit is that the 2775 is about 8 pounds lighter, and it can do anything with power boosters that you mention which a 2850 can do.. -ww.

  3. William,

    Congratulations on this milestone! It is interesting to me to hear people who have no knowledge of the subject talk about Corvairs as “one of those 1960’s car engines”, when in actuality, the R&D has never stopped. It is rare to hear anyone talk abut Continentals and Lycomings as “those engines from the 40’s and 50’s”, yet little has changed with those engines over the past decades. At the same time you never stop working to make the Corvair option better and better. Keep up the great work.

  4. Mr. Wynne,
    I know you field many outlandish “what if” emails but I need to pick your brain on a build that I am pricing. My background is a past Army and ASE mechanic (A1/A8, A5 & A6) that went back to school to get my Electrical Engineering degree. I’ve been working as a professional engineer for the past 20 years but still build and wrench a little. In July of 2016 I met one of my dreams by earning my private pilot license.

    The fact that you post your research and the decisions that led you to a solution is really what draws me to your methods. I agree that taking moderate, planned steps in aviation is the safest route. Which is the reason I purchased my conversion manual (#866) last year to look at a build. To that end I was working up an estimate using your site and the SPA information when I stumbled into an idea for a 3.0L with less machine work and less non-corvair parts. You have probably thought of this already, but I saw no info on the following combination.

    I like the idea of having a new crank prepped for the 5th bearing by SPA. The incremental expense just seems logical since you have to ship a crank back and forth to have it prepped and have a bearing added anyway. If you run the numbers, a stroker crank from PSA along with your 2775 piston and cylinder kit gives you a 3.0L engine. Pi x ((3.437+.060) /2)^2 x (2.940+.312) x 6 = 187.41cu.in. = 3.07L. So that’s roughly a 10% increase in volume “IF” the rods will clear the 2775 skirts and the base of the jugs. Even if you only gain a 5-8% performance increase, it’s basically free if you were planning to buy a new crank anyway. The aim isn’t to be cheap, it’s actually aimed at buying new parts. Just possibly another option without jumping to the next level of the 3.3L beauty.

    Conversions from basic to 3.3L run the same intake and carb so the increased velocity of the pistons using a stroker crank shouldn’t be an issue. You’re flowing a smaller volume of air than a 3.3L at what should be the same intake velocity since it is the same crank as a 3.3L. I need to see if SPA would even sell a stroked crank outside of their 3.3L kit, but are my numbers correct and would it physically work with the 2775 pistons, rods and jugs?

    Best Regards,
    David Gerdeman, PE

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