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PostPosted: November 15, 2017, 3:37 pm 
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Location: ontario
The engine is 2.7 L flat six, air cooled produced by GM between 1959 and 1969. (approximately 1.7 million units produced).
Engine weighs 230 lbs according to GM.
Transmission. Manual. 45 lbs
Differential. 70 lbs
Drive shafts (2) 6 lbs each
Clutch and flywheel 25 lbs
Starter 15 lbs.
Bell housing 6 lbs
These are the basic weights for a 1965 Corvair (my donor).

All this made (makes) for a remarkably light engine. The weight of the engine only without a flywheel was a factor in this engine's second career in general aviation where a large number of units have been rebuilt, converted to up to 3.1 L. The whole scene supported by a large number of dedicated engineers and vendors to this day.

As a car powering engine the Corvair 2.7 L has equipped numerous kit cars and dune buggies and still does. The maintenance and repair of these engines is relatively easy. The main dealer is IMO Clark's corvairs in Massachusset. I have bought a rebuilt transmission and differential from California Corvairs too. Both outstanding operators. Corvairs also have two rather large, busy and extraordinarily well connected forum membership including the participation of well known writers on this GM car.

The early Corvair was designed by GM to compete with VW and Renault. The original Corvairs were aimed at the working class family. A cheap car. The engine 140 ci was not outstanding (about 80 hb). The rear suspension (swing axles like the VW, BMW, Renault, Fiat etc) caused instability in a car that was longer and heavier than its European cousins. Commercially the car did not end up competing effectively with VWs and disappointed GM. However, Corvairs found a market that GM did not target: sporty drivers. A faithful following started and still lives to this day of people who enjoyed this remarkable vehicle. What they liked was the responsiveness of the air cooled flat six (the engine crank needs no counterweights), its lightness and in many cases the thought of driving the poor man's Porsche. GM banked on this unexpected market and changed strategy. The Corvair was extensively rethought in 1965. A new engine 164 ci with a base Hp of 110, 180 (at 4500 rpms) with the turbocharged version. The main change however was the rear suspension. The 1965 Corvair lost its swing arm system and was equipped with the type or rear independent suspension to be found on more elaborate cars such as the GM Corvette and Jaguar. Picture the rear suspension with not two universal joints but four. That way the rear wheels always remain perpendicular to the ground, addressing the stability issue. These cars were successful on the roads and races. However. the public relations negative campaign started by Ralph Nader in 1963-64 contributed to give the car a bad name and GM, I have read, decided around 1967 not to invest further in this line of product. Some observers have noted that GM was not forced into abandoning the model by Ralph Nader's bad press but rather because to carry further the development of this air cooled vehicle (and compete with Porsche) would take investments that they would rather make elsewhere. The last kick at the can (engine wise) was a flat six with overhead cams, capable of 7000 rpms and more than 250 hp. This engine never reached production.

Altogether, looking back at the Corvair adventure, I am sorry that GM did not persevere. Today we could have on the road North American cars that would potentially out perform Porsches

To us Locost seven builders, the Corvair engine is an interesting but marginal engine. One has to like the sound and the spontaneity of the flat six and rear drive engine to embark on a Corvair powered Seven build. In my case, I am rebuilding for my Locost a 1965 Corvair engine with 4 carbs, a sporty cam, a supercharger, water injection, a performance exhaust system. My expectation is 180 hp. Possibly 200. One last word: it will not be a LOW COST project when I am done.


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Last edited by phil on November 16, 2017, 5:46 pm, edited 4 times in total.

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PostPosted: November 15, 2017, 4:11 pm 
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I am going to be making a few Weber IDA-3 to Triumph MC ITB conversion plates.
I've seen lots of Corvair to Weber IDA-3 modified heads on feeBay but the cost of IDA-3's has gotten crazy.
Just another option if you're looking at MS anyway.

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PostPosted: November 15, 2017, 4:33 pm 
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That's quite the infomercial! Where are the pictures of it in your Locost? For me, engine choice depends on being able to walk into a parts store and get parts. Not sure this one passes the test.

I'm skeptical about the transmission weight. I recall my all-aluminum Honda transaxle weighing about 85 lbs, around the same as a Miata transmission.

It's also amazing the power output difference between those engines and today's. All that work, a turbocharger, and 150 hp is it?

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PostPosted: November 15, 2017, 5:12 pm 
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Location: ontario
RichardSIA wrote:
I am going to be making a few Weber IDA-3 to Triumph MC ITB conversion plates.
I've seen lots of Corvair to Weber IDA-3 modified heads on feeBay but the cost of IDA-3's has gotten crazy.
Just another option if you're looking at MS anyway.



Thanks,
I already have 4 single barrel 34 ICH webers. I take that moving from 2 to 4 carbs (even ordinary ones) will provide a jump from 110 to 140 HP (on paper). My hopes are rather invested in a small turbocharger which I have bought and which I will discuss if any one is interested :cheers:


Last edited by phil on November 15, 2017, 8:14 pm, edited 1 time in total.

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PostPosted: November 15, 2017, 5:29 pm 
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KB58 wrote:
That's quite the infomercial! Where are the pictures of it in your Locost? For me, engine choice depends on being able to walk into a parts store and get parts. Not sure this one passes the test.

I'm skeptical about the transmission weight. I recall my all-aluminum Honda transaxle weighing about 85 lbs, around the same as a Miata transmission.

It's also amazing the power output difference between those engines and today's. All that work, a turbocharger, and 150 hp is it?



Not to worry I have no shares in Clark's Corvairs. I was only trying to file a summary of my experience with this engine so far.
I have posted pictures of a variety of engines other than mine because mine is in many pieces, rather uninteresting, sitting on shelves. However here is a photo taken a year ago when I pulled the engine out of a Corvair I just bought.

You cannot "walk and get parts" with the corvair engine But you can order parts online. That's how I do most of my shopping nowadays.

The transmission? Well I put mine on a scale. That's what I read. May be the scale is wrong. My 1991 Suzuki Samurai transmission was 55 lbs???? Hummm. I will try to check this.

Yes the 1965 pushrod engine cannot measure up to modern fuel injected bangers. I never thought that was my point. IMHO HPs are not everything. Flat engine such as the Porsche's are highly responsive because as I said the crankshaft does not need to be counterbalanced. The Corvair can be pushed up to 5500 rpms as is which is not much. But at that speed stock GM cars were developing 180 hp. My hope is that with my own project I will get 180 to 200 hp. This is with 4 carbs. In a modernized engine, with EFI and better ignition control, I was told by folks on the Corvair Forum that 250 hp would be common. The bottom line is I am not here to advertise the Corvair engine but to provide what I think may be interesting reading to some. A push rod engine will never be able to compete effectively with overhead cam equivalents. Some have argued however that on the scale of things below 6000 rpms the pushrod design is still the most reliable (don't kill the messenger!!!) :cheers:


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PostPosted: November 15, 2017, 8:57 pm 
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Many years ago I did some work on a custom bodied Corvair.
The car itself was not too special.
But the engine was a GM Experimental prototype with one-piece heads and cylinders similar to several aircraft engines.
It also had a very light plastic cooling fan.
Not sure if the car's restoration/modifications were ever finished.
It may still be in the SF bay area. :?:

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PostPosted: November 15, 2017, 10:41 pm 
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RichardSIA wrote:
Many years ago I did some work on a custom bodied Corvair.
The car itself was not too special.
But the engine was a GM Experimental prototype with one-piece heads and cylinders similar to several aircraft engines.
It also had a very light plastic cooling fan.
Not sure if the car's restoration/modifications were ever finished.
It may still be in the SF bay area. :?:


Thanks,
I would be curious to see that. All I know of is that in the seventies the Corsa newsletter published the story of a guy who fitted water cooled heads (not a one piece head-cylinder)on a performance corvair engine. As you probably know, overheating was part of the corvair engine challenge :cheers:


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PostPosted: December 15, 2017, 9:53 am 
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[quote="KB58"]That's quite the infomercial! Where are the pictures of it in your Locost? For me, engine choice depends on being able to walk into a parts store and get parts. Not sure this one passes the test.

I'm skeptical about the transmission weight. I recall my all-aluminum Honda transaxle weighing about 85 lbs, around the same as a Miata transmission.


I checked the transmission weight with another scale. The reading is 50 lbs instead of 45 lbs as I previously stated. Sorry for the error.


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PostPosted: December 15, 2017, 11:59 am 
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I think Kurt missed that the diff was weighed separately, his Honda and most transaxles are one-piece. He's not trying to rain on your parade the progress in cylinder head and cam shaft design has been remarkable.

Over head cam engines are mostly more efficient when you measure the engine displacement. That is not such a real thing though it's a measure of the empty space inside the engine after all. It's an issue pushed by things like tax laws and racing rules. If you measure the weight of an engine or the total physical size then push rod engines start to look more efficient.

Airplanes use pushrod, large displacement, horizontally opposed engines because the laws of physics are more important than tax laws or racing body rules. My recollection is that a Lycoming 360 CID engine with 180 HP weighs under 200 lbs.. It's possible that does not include the carb.

I'm sorry I missed this thread when you started. I am quite fond of Corvairs, the man who introduced me to road racing when I was in high school drove one. It was the best handling USA car at the time.

I looked at trying to fit a Corvair transaxle into a locost as a way to move some weight to the back of the car. It's a good unit and seemed relatively easy to mount etc.

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PostPosted: December 15, 2017, 3:01 pm 
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GM already did that, in the Pontiac Tempest. Same setup at the Porsche 928 and newer Corvettes.


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