A Flat 8 Corvair Engine

[valkry9]

So,like
I purchased 2 Corvair engines this past fall with the intention of simply re+re the 6 into my new 914.
Having had a look at the efforts a man in Australia has made to "make" a flat 8 Porsche engine,I have made the decision to emulate the idea with the Corvair engines.
A tall order,yes.A ton of work.Not only difficult,expensive too.
In researching I have found that only Bruce Crower attempted such an engine with Cosworth Vega heads.
(Other than aero apps,Northrop used twin engine Franklin-8s buried in the Wing)

Has anyone on board ever hear tell of such work by gm in the 50's?

Simple,right?Easy as Pie.
A measure of welding talent is required,with commensurate experience in 356 die castings.
Welding magnesium Porsche cases has got to be tougher.
Comment?

[miniman82]

http://oppositelock.jalopnik.com/flat-1 ... 1561901258


I spoke with Ray Sedman about having a billet 8-cylinder crankshaft made for such an engine, and he said he would be happy to do the work but that the cost would run somewhere north of $2000. I have a pair of engine cases squirreled away in the garage for whenever I am finally able to scrape up enough money to actually go for it, till then it's just a crazy idea I had been kicking around. Even have the TIG machine now to be able to join the cases together.

Biggest problem is that no 2 cases are alike when it comes to dimensions, meaning you can't even align the crank/cam tunnels between the two in order to weld them together. Instead you would get them close enough, keeping in mind the top cover and oil pan surfaces, do the welding, then linebore both tunnels and machine all the other surfaces to make them match. A lot of work to be sure, but it could be done. I anticipate I'll have my own mill capable of doing this work myself before beginning, which means it could be a lot of years before I get around to it. Only when I am successful in joining the 2 will I give Ray a call, so he can chuck me up a piece of 4340 and go to town on it...

Then there's the heads- since the cylinders come in 3's, you have 2 options:

1. weld a 4th cylinder onto a Corvair head, do the necessary machine work- do this twice.
2. Cut a cylinder off a Corvair head, then simply add the valve cover rail- do it 4 times.

Personally I'd rather have 2-cylinders/head rather than a super long 4-cylinder one, for the simple fact that it would be easier to do and it would also be easier to remove/replace 2-cylinder heads in the event something goes wrong. And you still have all the other problems with how to cool it and handle induction, but those are simple compared to assembling the longblock for sure. My engine would be fuel injected with ITB's, but would be set up for low RPM torque production with a roller cam- another Sedman part.

[Augie]

I believe GM has already done this in a 8, 10, and 12.

[azdave]

Read #20.

http://articles.chicagotribune.com/2009 ... end-heater


20. Modular Corvair engines were built to bolt together in 4-, 8- and 10-cylinder configurations. One, a 10-cylinder front-wheel-drive configuration, was used in the development of the Olds Toronado.

[valkry9]

Incredible.A ten!
This is good news,that GM did it all in the early 60's has made my day.Not only was it a viable idea then,it still is.
Some modifications for a 21st century world and it will be good to go.All of the above and then some,even the TwinCam.
A long term endeavour for a unique result.
1.)Get 2 engines.check.
2.)Weld wirecut or machined cases to best fit together,front 2 + rear 2=8.
3.)Cylinder heads also front 2 + rear 2.
4.)Crank and cam to custom specs,sizes.
5.).....more to come.

[azdave]

Matt over on Corvaircenter saw this discussion and sent me this old photo of the GM prototype 10-cylinder Corvair engine.


Some other cool prototype Corvair engines here.
http://blog.hemmings.com/index.php/2010 ... -stratton/

[valkry9]

Metal Casting in non ferrous alloys:
https://www.youtube.com/user/myfordboy
Years ago I recall the saga of a custom Jaguar powered custom roadster of a certain 30's design.
The unique aspect was the direct crank driven blower,in the style of W.O.Bentley's earlier bigmotor behemoth.
The builder wanted something that fit perfectly between the frame rails and around the busy area of the transverse crossmember.
As it was necessary to make a cast housing he inquired at the foundries of SoCal and was told the deeply finned design was too difficult to do.
"If the founders of Italy could do it in the 30's why can't you?"he inquired.
The challenge was met and his exquisite blower housing was a work of the moulder's art.
A diecast flat 6 engine redesigned for a sandcasting method is no mean feat.
http://www.polomotor.com/
So then,the objective is the patternmaking,moulding and pouring of a flat-8 Corvair engine block and heads.
https://www.youtube.com/watch?v=B5wCVI7 ... 3088#t=204
http://www.youtube.com/watch?v=7adNd2VctmI#t=99
And,an additional enhancement of the 50's design.
Utilizing off the shelf parts.
gonna be fun.

[valkry9]

Anyone here recall this article?
Does anyone have the full text?
So,if an early visionary built this engine that long ago,whatever happened to it?
(note:This is not an -8,but rather an 8 carb setup.)

[bbodie52]

The article appears to focus on some efforts to experiment with Corvair intake modifications. The engine on the cover looks like it has eight Dell'Orto Italian motorcycle carburetors mounted.



A used copy of this issue would be easy to obtain. A quick search for "Hot Rod Magazine February 1963" on eBay produced over 30 results for about $4.00 and up.

http://www.ebay.com/sch/i.html?_odkw=Ho ... 3&_sacat=0

http://www.ebay.com/itm/Hot-Rod-Februar ... 5d4fa9d0cf

It can even be purchased on Amazon.com...

http://www.amazon.com/Magazine-February ... B005IHT2JK

Interesting that this experimental highly tuned Corvair engine on the cover was apparently configured to mate to a 2-speed Powerglide transmission... not exactly considered an optimum performance setup!

[valkry9]

I initially figured the engine had been done to 8,but on closer inspection saw that it was indeed 6 iron cylinders.
The DellOrtos look the business,very sophisticated for '62-'63.I'm incllned to think the response was smooth and sweet sounding.
I never had a copy of the HRM,though I do recall seeing it on the stands at the hardware/general store.
The very different Corvair in those days was still novel to the general public.

Interesting aircooled Tatra 2.5L V8 from Czechslovakia.
Manufactured for 60+ yrs,must be a lot of them.
Does anyone here have any data regarding bore/cylinder stud spacing?
603=75/72mm BXS
later
613=3.5L,4.3L model w DOHC.

07-tatra-blocks.jpg (14.7 KiB) Viewed 16386 times

H-4 SOHC 1.5L 1937?
reminds me of the Astro Heads.
simplify a similar install on a corvair shortblock.

[martyscarr]

Does anyone here have any data regarding bore/cylinder stud spacing?

Not sure if the book "Air Cooled Motor Engines" would have any engine specifics, but it does contain a lot of info about Tatra engines. It is written by Julius Mackerle, who was chief engineer at the Tatra factory. It is a rather expensive book but you might be able to borrow a copy through inter library loan. Search worldcat.com for a library near you that has it http://www.worldcat.org/title/air-coole ... ef_results

Marty Scarr

[valkry9]

Thanks for taking the time to search Martyscarr,much appreciated.
That's the first reference to the designer's book I've seen.
I am sure the info I'll require will be within.
I recall looking at the engines and their history many years ago and had always assumed
their design was of a utilitarian nature,with a wide range of applications.
Watching a pullrope start of a 603 has validated that observation.
http://www.youtube.com/watch?v=upvpMCnnSq8
No battery?no problem,use a strap.

[valkry9]

bare block
Tatra 613 3.5/4.4L DOHC V8
integral differential housing,axle under crank

cam carriers removed

reminds me of the Astro
gee I wonder if they would fit.

a link to info(not english)
http://www.lhotkanet.cz/mirror/aek4470.finalnet.cz/

[valkry9]

a sophisticated aircooled 3.5/4.4L dohc 16v v8
axle passes below crank about an inch
model#613=4spd
model#700=5spd

[MBlaster1]

Here is a lot of engines you might use for parts.
http://losangeles.craigslist.org/sfv/pt ... 56237.html" onclick="window.open(this.href);return false;

[Wagon Master]

If space was no concern, I would think it would be a lot more cost-effective to go with a flat 12 instead of a flat 8 or 10. Just need to couple the ends of the crankshafts together. Let each engine rotate its own cam.