Corvair gut check

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Little Scrapper

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Hey guys. I’m exploring engine options For the Baby Ace and a Corvair came up as a possibility. While I have quite a bit of auto and motorcycle engine experience I’ve never worked on a Corvair and haven’t researched the actual conversion much. So looking for some simple advice to start out with.

Knowing this was a option I reached out to a airplane friend locally and as it turns out he has a complete original 110 engine yanked out of a 64 and it’s never been touched, 40k mile car. He’s now in his late 80’s and said to just come and get it.

So it’s available for free but before I commit I’d like to know what I’m up against as far as building a engine mount, rebuilding this, 5th bearing etc. What are some of the things to know about Corvair conversions and weight that could get me up to speed with just some general knowledge before I commit and go down this road. Seems like a big engine for this but not sure. What are your thoughts.

Will Aldridge

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One good site to peruse is n56ml.com. Mark Langford installed one on his kr2s. He did the big bore version and had 3 crank breaks. The last resulted in enough damage to the plane that it hasn't flown in years.

GeeZee

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I like the vairs a lot. I have one about ready to put together. A must have is William Wynnes conversion manual. Contains many many years of what works and what does not. He sells a bunch of parts for conversion that you may be able to fab on your own. The real must haves are the fifth bearing, Prop hub And maybe the distributER. The things like the starter conversion, alt bracket, intake and exhaust are pretty DIYable (especially for you).
The fifth bearing pretty much eliminated crank breakage. That was the last piece of the puzzle that really makes the vair a very nice AC engine. Total weight should be around 220lbs. If that engine weight works for the baby ace, I say go for it!

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Don't judge the Corvair by what happened to Langford's engine. Things have changed in the last several years. First thing to do is get the Corvair builders manual from William Wynne 0100 Corvair Conversion Manual Then you can spend a few days reading through all of the blog posts on the Corvair website.

That will get you well educated on what is needed to build a good running engine. One of our frequent posters, Dale Williams, has a Wynne Corvair in his Sonex and seems to love it.

GeeZee

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Oh yea , Mark and William were friends but have had a major falling out so if you visit Marks site take what he says with a grain of salt (as they say).

TFF

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Corvair, like VW, if overworked will break. The Corvair though is in the Continental realm of power per weight per cubic inch. Run a Corvair at 120 hp +, like trying to put it in the place of a O-200/O-235, is pushing it. Run it at 70 hp and it’s happy.

Plus side.
Three or more companies doing conversion packages plus you could get the original Piet drawings.
Parts are really not an issue.
USA baby!
Smooth runner.
Different without being too different.
Weight right at what a Continental weighs.
Be fun to build.

Minuses
Still not as robust as a regular airplane engine.
Got to find a good core. They haven’t made them in a long time.
It is a DIY project, not off the shelf like an engine design for an airplane, no matter how nice the conversion. More custom than the VW.
Might not be fun to build if you have problems.

Not sure
Is there a magneto ignition available if no electrical is preferred?

In a Baby Ace it would be like having the C-85 in It. It would have pretty good homebuilt street cred.

TerryM76

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FWIW....I have been considering using a Corvair engine in a project for quite a while. I've accumulated 6 cores in the past 5 years and have distilled it down to building a basic 2700cc engine and a 3000cc engine....through one purchase that I've made, Ive got over 85% of a 3000cc engine currently in work and maybe 40% of the basic engine. These engines offer simplicity and relatively low cost with demonstrated reliability. The engines are neither the lightest or the most powerful for their weight. I like that there is a high level of support and different aircraft applications. I haven't completely decided upon which airframe I would like but have few reservations about implementation.

Since you can get an engine core that hasn't been molested, you will gain a considerable amount of knowledge through tearing it down and determining the viability of engine components. Cleaning the case and heads will take some time.

Little Scrapper

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FWIW....I have been considering using a Corvair engine in a project for quite a while. I've accumulated 6 cores in the past 5 years and have distilled it down to building a basic 2700cc engine and a 3000cc engine....through one purchase that I've made, Ive got over 85% of a 3000cc engine currently in work and maybe 40% of the basic engine. These engines offer simplicity and relatively low cost with demonstrated reliability. The engines are neither the lightest or the most powerful for their weight. I like that there is a high level of support and different aircraft applications. I haven't completely decided upon which airframe I would like but have few reservations about implementation.

Since you can get an engine core that hasn't been molested, you will gain a considerable amount of knowledge through tearing it down and determining the viability of engine components. Cleaning the case and heads will take some time.
Why 6 cores? Were they all bad?

Last edited:

TerryM76

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I really only had one core with unusable heads due to corrosion and that was with the first pair that I bought. The second two cores came with many new parts and for whatever reason I ended up with a 5th core. I'm also looking at building up a "new" engine for a relative's car. The 6th core was the 3000cc engine that has a completely assembled bottom end with 5th bearing already in place.

Seems like Corvair cores are like potato chips......

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From WW's blog:
We sell complete engines from $12,750 to$17,750. However, 90% of our builders assemble their own engines working from our Conversion manual, DVDs, parts and support and a rebuildable core engine they pick up locally. Typically, they budget $8,500-10,500 to build a first class, zero timed, engine. Budget motors can be built for as little as$6,500.

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Corvair, like VW, if overworked will break. The Corvair though is in the Continental realm of power per weight per cubic inch. Run a Corvair at 120 hp +, like trying to put it in the place of a O-200/O-235, is pushing it. Run it at 70 hp and it’s happy.
Power: Corvairs have several different power ratings. 100, 105, 110, 120 and 125+hp. These correspond to the five displacements listed above. They make their rated power at 3,150 rpm. They have wide power bands, making 75% power at 2,650 rpm. All engines will exceed their rated power at higher rpm, and they can be continuously run at full power at 3,400 rpm without damage.

don january

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Mike. If you study into the Corvair engine you will find that the 164 ci engine is the one to go with for a build. The 145 ci can be done but the rods are to weak and if built with the desired crank shaft you will need to remove material inside the block to get bolt clearance and the location is not in a very good place. To get the right engine to convert is not like reaching into a bag of potato chips but more like a bowl of half burnt pop corn because a person has to pick through the pieces and get the best snack. 220 lb. weight is not that easy to meet but doable and don't forget they don't make new blocks for the Corvair any where. The Subaru is close to the same weight built for flight but water cooled and more FWF work to be done but parts are available from block on up for the Subs and by the way I flew my KR-2 behind a 145 ci Corvair back in the day before all the gold goodies from W.W. was available. I have a manual from WW and would be glad to mail it to you for you can research things deeper if you like give me a PM if interested. Don

Little Scrapper

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Mike. If you study into the Corvair engine you will find that the 164 ci engine is the one to go with for a build. The 145 ci can be done but the rods are to weak and if built with the desired crank shaft you will need to remove material inside the block to get bolt clearance and the location is not in a very good place. To get the right engine to convert is not like reaching into a bag of potato chips but more like a bowl of half burnt pop corn because a person has to pick through the pieces and get the best snack. 220 lb. weight is not that easy to meet but doable and don't forget they don't make new blocks for the Corvair any where. The Subaru is close to the same weight built for flight but water cooled and more FWF work to be done but parts are available from block on up for the Subs and by the way I flew my KR-2 behind a 145 ci Corvair back in the day before all the gold goodies from W.W. was available. I have a manual from WW and would be glad to mail it to you for you can research things deeper if you like give me a PM if interested. Don
Did you like flying behind a Corvair?

Victor Bravo

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I hope I'm not puncturing anyone's balloon, but what is the actual real-world FWF weight difference between the Corvair and a standard A-65? If they're the same, then I say go for it, make up amount for the Corvair and just design it so you will be able to go back to the A-65 if you want to. If the A-65 is 25, 40, 50 pounds lighter than the Corvair, then the weight - plus the weight and balance issue - favors the old standby Continental.

Little Scrapper

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I hope I'm not puncturing anyone's balloon, but what is the actual real-world FWF weight difference between the Corvair and a standard A-65? If they're the same, then I say go for it, make up amount for the Corvair and just design it so you will be able to go back to the A-65 if you want to. If the A-65 is 25, 40, 50 pounds lighter than the Corvair, then the weight - plus the weight and balance issue - favors the old standby Continental.
Agreed!

Just exploring here and asking for thoughts and opinions. Weight is not making me feel comfortable right now based on my reading. Corvair is pretty heavy.

TerryM76

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One of my goals is to do a weight comparison with a Continental C-85 and I would do that with an A65. I need to source an A65 for a Luscombe project.

don january

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Mike. "NO" at the time it was a very new auto conversion for me and caused a fair share of stress. Also with the weight of engine the KR-2 was a hand full with 2 souls on board and full fuel. I would consider a Aeromomentum 107 HP for the Baby Ace or the KR-2 if I was to go auto conversion. JMO

Little Scrapper

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I just ruled this engine out for the Baby Ace. I appreciate everyone’s input.

For the record I am NOT against the Corvair I actually like it quite well. It’s just not a good fit for my application.

Mike

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