Carburetor for Corvair???

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

buzzbauer1

Active Member
Joined
Jun 27, 2007
Messages
40
Location
Tallahassee Florida
One thing i am not sure of and have seen very little posted is carburetor on the Corvair conversion motors. DO I need the stock carburetors that come with the car. I have bought a motor and another is available, but he wants to keep the carbs. DO I need them or will I use another Carb from another source? Thanks, I am new and literally just starting. I don't even have possession of the motor yet.
 

Dave068

Member
Joined
Mar 20, 2005
Messages
8
The best start to get is go to www.flycorvair.com. Read the info William Wynne has presented and order his conversion manual, it will greatly help your quest.

The simple answer to your question is no, you will not need the stock carbs.
 

spduffee

Well-Known Member
Joined
Sep 22, 2011
Messages
569
Location
Renton, WA
Has anyone actually used a Corvair carb on their conversion? Wynne mentions it in his manual, as in "some have even used stock Corvair carbs with success", but nothing more than that. I have 4 at home, but they are from a 1964, 90hp. Would they also have to be from a 1965-69 too, like the rest of the conversion donors? I think ultimately I would like to go with an Aeroconversion carb (typical on and produced for Sonex), but for run ups now I would like to be able to use what I have. Any advice would be welcome.

Thanks,

Shawn
 

spduffee

Well-Known Member
Joined
Sep 22, 2011
Messages
569
Location
Renton, WA
Thanks.... I have a copy of his conversion manual. It only mentions the Corvair carb. He can't be reached, either by email or telophone. I guess he must be down at the Sebring events?
 

fredoyster

Well-Known Member
Joined
Mar 20, 2012
Messages
333
Location
Monterey Bay, CA
Thanks.... I have a copy of his conversion manual. It only mentions the Corvair carb. He can't be reached, either by email or telophone. I guess he must be down at the Sebring events?

Perhaps you should look at the manual more, or see Max's link. WW suggests either a Marvel-Schebler MA3-SPA or a Stromberg. If you dig on his site you'll find mention of a Carter automobile carb that would also work.
 

TFF

Well-Known Member
Joined
Apr 28, 2010
Messages
17,984
Location
Memphis, TN
I bet if you are not trying to go all out with HP, it would work. If it is weezy, change it after testing.
 

Pops

Well-Known Member
Supporting Member
Joined
Jan 1, 2013
Messages
11,521
Location
USA.
One of my neighbors built a Piet and bought the Corvair engine from William Wynne and it had a Marvel Schebler on it.
 

spduffee

Well-Known Member
Joined
Sep 22, 2011
Messages
569
Location
Renton, WA
Thanks for all the replies.
I have a converted engine, minus the carb (didn't come with one). I want to get it up and running for now and I have 4 Corvair carbs in my garage that I could use right now. I wanted to hear from anyone actually using the Corvair carbs. No biggie. It was a bad idea anyway, since the intake on mine is made for an updraft and was originally fitted with an MA3. My aim is to eventually fly it with an Aerocarb. It's not at the top of Wynne's list but is acceptable and I like the simplicity of it. Even on Ebay the MA3's are going from $400-700, unknown condition. I will scrap the idea and just buy the carb I need for the final setup. Thanks again,

Shawn
 

dcstrng

Well-Known Member
Joined
Oct 17, 2010
Messages
913
Location
VA or NoDak
Just to get it running you could use almost any carb that will run a 50-100hp sized engine – I wouldn’t, however, plan on doing any “tuning” and certainly not use the WW style of aggressive advance as your mixture could be all over the place… WW has experimented with all sorts of carbs but seems to have moved far away from his earlier Pietenpol-eque precepts of an automotive style engine with readily available parts to more or less converting the Corvair into a Continental – his earlier writing s will probably be more useful for “start-up” purposes… In any case, with a cobbled together carb set up I would not operate any anywhere near full load nor with full advance until you are absolutely confident the mixture is spot-on – unless you have all the parts at hand, my guess is you’d be money (and a whole lot of time) ahead to simply invest in whatever you plan to fly with…
 

Pops

Well-Known Member
Supporting Member
Joined
Jan 1, 2013
Messages
11,521
Location
USA.
Thanks for all the replies.
I have a converted engine, minus the carb (didn't come with one). I want to get it up and running for now and I have 4 Corvair carbs in my garage that I could use right now. I wanted to hear from anyone actually using the Corvair carbs. No biggie. It was a bad idea anyway, since the intake on mine is made for an updraft and was originally fitted with an MA3. My aim is to eventually fly it with an Aerocarb. It's not at the top of Wynne's list but is acceptable and I like the simplicity of it. Even on Ebay the MA3's are going from $400-700, unknown condition. I will scrap the idea and just buy the carb I need for the final setup. Thanks again,

Shawn

If you are not going to have a starter on your engine, have you thought about what happens to the engine if you get an air bubble in your fuel line when using a carb without a fuel bowl? And if you have a starter, enough time to try to restart.

Dan
 

spduffee

Well-Known Member
Joined
Sep 22, 2011
Messages
569
Location
Renton, WA
If you are not going to have a starter on your engine, have you thought about what happens to the engine if you get an air bubble in your fuel line when using a carb without a fuel bowl? And if you have a starter, enough time to try to restart.

Dan

Hmm... It does have a starter, but point well received. The bummer is, I recently sold an MA3 for next to nothing to a friend when I swapped out the engine on the 170A. It came with one better than my own. Time to go looking for another, I guess.
 

William Wynne

Active Member
Joined
Jan 24, 2015
Messages
30
Location
JacksonVille FL
Notes on Carbs for Corvairs:

While several of the comments on this topic were well considered, I would like to single out "Max Torque", for posting the correct link on our website and also mentioning the value of using the search boxes on the front pages of our sites. Mr Torque has been around flying Corvairs for 15 years, has been to the Colleges, has a lot of GA experience, and judgment and experience in flying that are had to overstate. He keeps up on Corvair developments and any comment he makes on Corvairs or flying is well worth reading.
.
As posted, our Carb Reference page is: Carburetor Reference page | flycorvair
If you sat down with a cup of coffee 3 evenings in a row, you could read the whole thing, including the embedded links and the sub stories. It isn't all dry, there are observations on carbs like the one I excerpted at the bottom of this post.
.
For people on the same topic, fuel systems, please note that I also have a Fuel Injection reference page that includes both mechanical and Electronic systems: Fuel Injection – Corvair flight engines reference page | flycorvair As you look through it it has many pictures of engines on our Dyno, and testing we have personally done. As you read through many websites about engines, just stop and note how many people claim to definitively know something to be true, but can not produce a single photo of any test of it. I have read perhaps 100 engine brochures speaking of dyno runs, but only seen maybe 5% of the same engines on one....as if photography was a more complex process than running an engine on a dyno. Think that over.
.
Random Carb thoughts:
.
I am not a big fan of Aerocarbs on Corvairs, and I would highly discourage their use in any application which is not gravity feed, and discourage their use in any new airframe / Corvair combination. They have tuning requirements that most builders are simply not up for. I am friends with the Monetts, and they don't take it personally when I say this.
.
The Correct MA3-SPA is the 10-4894 model only, this is the one for an O-200. The one from a Cessna 170's O-300 will not work well unless it has all it's guts converted to the 10-4894's, which isn't something to do at home as your first carb rebuild. Our manual lists a very good source for the correct MA3s and Strombergs in Michigan.
.
Don't try stop gap carbs on planes, it is a bad idea. Example, MGA carb on 601XL: How I became a genius in 6 minutes | flycorvair Just put the final carb on the plane you are going to use. Build your plane to the best standard you know of the first time.
.
We have a tremendous amount of data available to serious builders on our invitational discussion groups: ‘Zenvair’ Information board formed | flycorvair We have 50 flying guys on there, all with real names as known builders and flyers, who are accumulating and comparing CHT and EGT data operationally. The format is organized and moderated by this guy: Guest writer: Phil Maxson, flying a 3100cc Corvair in his 601XL | flycorvair . The information we have is not limited to what I can personally generate, because the Corvair movement is based on learning and sharing and giving back, we have many people making outstanding contributions to data. Other companies attract people who want to buy an engine. We gather, and develop people who want to understand engines, and for this reason, we have a comparatively far deeper well of knowledge.
.
---------------------------------------------
.
On Stromberg Carbs:
.
"Consider this: The Stromberg on my wife’s plane was made just about the same time that the Soviet Red Army adopted a device called the AK-47. Sixty plus years later, both of these devices have been used in countless numbers all over the globe. Both are often criticized as outdated, inefficient, inaccurate and stone age. Notice that their continued use in the face of all criticism is justified by the same three word sentence, “It is reliable.” People who have held either one in their hands, stared at its metal parts and though about how they would need to count on it, will have some appreciation for that three word sentence. If I can teach you only one thing about experimental aircraft, let it be this: There is no characteristic more important than reliability. Anything you could get in trade for reliability isn’t worth it." -ww.
 
Joined
Mar 24, 2015
Messages
8
Location
Coupeville, WA
I have almost 300 hours behind a Corvair motor built by Bill Clapp using an Aerocarb with fuel pumps. The set-up used the stock mechanical pump backed up by two facet electrical pumps and no gravity feed. The carburetor worked flawlessly through a Holley pressure regulator mounted on the firewall that entire time.

The one problem I had was the high failure rate of the mechanical pump diaphragm. These were only good for ~75 hours before they started to weep. Not good. The operation of the fuel system suffered no failures of problems other than the terrible mechanical fuel pumps.

Last year I converted to a gravity feed system to get rid of the mechanical pump while not relying solely on an electrically powered fuel feed. This set-up also allowed me to increase the range and safety of the bird by adding the feeder tank (3.5 gallons).

While I agree with WW's opinion the Aerocarb can be time consuming to adjust, once it is adjusted it works as advertised. I plan on putting one on my next aircraft, a Saberwing designed by Bill Clapp and powered by Bill's Corvair engine with a new crank.

One aviator's experience. Your mileage may vary. - Zip
 

rv6ejguy

Well-Known Member
Supporting Member
Joined
Jun 26, 2012
Messages
4,944
Location
Calgary, Alberta, Canada
WW's link about EFI is chock full of misinformation and opinion. If you want to use a carb, fine, they do the job but don't sprout nonsense like this with virtually no experience in the field. You can read my rebuttal here: http://www.sdsefi.com/air70.htm

1400 delivered aviation EFI systems over 21 years and 250,000+ flight hours says WW doesn't know what he is talking about: http://www.sdsefi.com/aircraft.html
 
Last edited:

TJay

Well-Known Member
Joined
Jan 18, 2014
Messages
201
Location
Maurice IA
I have the big Aero carb its the new style injector one. I bought it for the Corvair and decided to go a different direction. I would sell it for $150 plus shipping its real close to new.
 
Top