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Re: Special cylinder head engineeringdrawing
Posted by: ral1963 ()
Date: May 05, 2019 02:12PM

Found it, I had this snippet in my notes. I also had a note that just said Bob Helt, so I think this came from one of Bob Helt books, unless I just had that note there to ask him something...


A fuel injection system for the Corvair engine was considered one route to increased performance by Chevrolet engineering. In 1957, an optional mechanical fuel injection (FI) system was offered by Chevrolet to boost their 283 CID V 8 engine output to one horsepower per cubic inch – an industry first. This high-performance option was not without its problems however. It was rather expensive, selling for nearly $500 on a $2500 car. Also it was a very complex unit, prone to clogging, and not easily serviced. Since the FI units had to be calibrated on a flow bench to get the proper settings, most problems could only be fixed by installing a rebuilt unit, which was a very expensive was to go. But the FI did produce the desired power along with some excellent fuel economy due to its precise metering.

Could these obstacles be overcome for the Corvair engine while still delivering the anticipated high performance and economy? Chevrolet engineering thought it could be done and launched the Corvair FI development program.

The FI program started on 11 August 1962 with a series of pre-tests to evaluate feasibility. The fuel injection unit initially used was a mechanical injection system commercially produced by Marvel Schebler, a division of Borg Warner Corp. At the start, six individual ram pipes with no plenum were used. The test engine was already mildly modified for performance increases.

Displacement of this test engine was 164 CID (two years before release to production!). Highly modified Bill Thomas 4X1 cylinder heads with 1.70 inch intake and 1.38 inch exhaust valves were purchased and converted to accept the FI ram tubes. These same heads were also the inspiration for the 4X1 heads later released to production on the 140 hp engine. High-lift and long duration camshafts were purchased from Iskenderian and used in nearly all subsequent FI tests.

During the approximate 30-month development period, standard items on most FI engines included 164 CID, Isky camshaft and Thomas heads.


Rick Loving
Corvair historian & chronicler of useless facts
CORSA
Performance Corvair Group
Chicagoland Corvair Enthusiasts

RAL1963@COMCAST.NET
Just south of Chicago IL

Current Ride
63 Sprint Vert 140/4sp

Past Rides
60 700 Sedan 80hp PG
63 Monza Vert 102hp 4 spd
63 Monza Coupe 140hp 4 spd
63 700 Sedan 80hp 3 spd
64 Monza Vert 110hp 4 spd
64 Monza Coupe 95hp 3 spd
64 Monza Sedan 110hp PG
65 500 Coupe 95hp 4 spd
65 Monza Coupe 110hp PG
65 Corsa Coupe 140hp 4 spd
66 Turbo Coupe 180/4sp
68 Monza Vert 140hp 3 spd

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Re: Special cylinder head engineeringdrawing
Posted by: scottymac ()
Date: May 05, 2019 07:07PM

If you have access to the fastvair group on yahoo, Scotty Grover, beginning in 15 June 2015, has over 20 files of Corvair head design - individual heads, even double overhead cam designs. A sample -

Scott
Danville, In.
'65 Corsa basket case
'66 Monza coupe



Edited 2 time(s). Last edit at 05/06/2019 06:04AM by MattNall.

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Re: Special cylinder head engineeringdrawing
Posted by: SteveInMarietta ()
Date: August 26, 2019 06:22PM

Bill Johnson's CR-0001 drawing has finally been digitized. The 3' x 8' drawing is rather frail and required 48 separate scans, which were then photomerged. From the snippets reproduced above it's obvious that there was a lot of discoloration which adds a lot of size (64 MB ) to the final image. To make it more portable, I photoshopped out the background as best possible, with a little loss of resolution, and moved some of the individual drawings into closer proximity to reduce the image dimensions. The file I have posted here is about 3.5 MB.
Comments on the drawing?
Steve

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Re: Special cylinder head engineeringdrawing
Posted by: MattNall ()
Date: August 26, 2019 06:36PM

Thanks for your efforts!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Special cylinder head engineeringdrawing
Posted by: vairmech ()
Date: August 26, 2019 06:38PM

Having just seen an original set of Bill Thomas heads they were indeed 60 heads! The valve angles were noticeably wide with dual valve springs and very large valves. There was also angled exhaust ports. I may get a chance to see the complete setup with headers later on.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Special cylinder head engineeringdrawing
Posted by: v8vair ()
Date: August 26, 2019 07:07PM

I know Bill Thomas gets all the credit but Mike Jones did a lot of the development work for Bill, From everything ive read Mike was a major part of 361s success.

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Re: Special cylinder head engineeringdrawing
Posted by: ROD ()
Date: August 26, 2019 07:48PM

Neat drawings thanks for posting.

Rod Tetrault
El Cajon , CA
65 Corsa Yenko Clone / 65 Corsa EO Creampuff Vert
66 Corsa "JIMISH" Mid engine Turbo LS1 currently 2nd fastest Corvair in the USA
Class 5 Corvair powered Baja
Corvair powered Buggy x 3
Enough hidden parts to build a space ship

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Re: Special cylinder head engineeringdrawing
Posted by: chris ()
Date: August 26, 2019 08:13PM

v8vair Wrote:
-------------------------------------------------------
> I know Bill Thomas gets all the credit but Mike Jones did a lot of the development work for Bill, From everything ive read Mike was a major part of 361s success.

Not only that, but didn't Mike do a lot of the driving on the cars?

'65 Monza 4 door
4 speed
110hp
Gardner, KS

Heart of America Corvair Owners Association

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Re: Special cylinder head engineering drawing
Posted by: kdrolt ()
Date: August 27, 2019 06:23AM

YES that dwg is worth digitizing.

BT was modifying heads at the very beginning of hot rodding Corvairs. One of the first set of mods was using larger "Corvette: valves, aluminum pushrods, higher ratio rocker arms (from the 348/409 v8 engine), compression ratio increase, and cam swaps. Further changes were 4x1 carbs, rotated for non-flooding. GM actually obtained Thomas heads to evaluate, and these were no doubt the inspiration for the so-called 140 hp heads.

So it makes sense that BT would have created a head dwg, based on a GM dwg for a stock head (with quench on the 95hp, 98hp, 102hp probably as the starting point) with the appropriate changes to make it breathe better. GM obtained modified heads from BT, and chances are they got a copy of the BT dwg as well.

Very cool find.

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Re: Special cylinder head engineering drawing
Posted by: kdrolt ()
Date: August 27, 2019 06:39AM

Differences & observations
1.50" intake valve (140s got 1.72")

Spark plug boss is positioned closer to the chamber center for faster burn (just like modern heads, and UNLIKE all Corvair heads).

3.74" bore, as approx used on 140 cid engiens of 1960 model year


Squish regions below the valves (large area) and on spark plug boss.

Straight entry tuned intake runner with integral stiffening flange that also serves as the rocker pocket. Intake runner has same ID as intake valve (1.50").

It appears to be a modular head but it could also be that the author showed only the details for each cylinder, and could have used a separate dwg to detail the 3-in-1 casting.

Not sure if there are provisions for air cooling tins, which would suggest drag use only.

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Re: Special cylinder head engineering drawing
Posted by: martyscarr ()
Date: August 27, 2019 11:04PM

Steve - Great job on the cleanup of the old drawings, it's great to see what Bill Thomas was doing.

Ken Hand, did you happen to take a picture of the heads you saw?

Anyone else have any pictures to show?

Anyone have a picture of an assembled engine with the heads?



Edited 1 time(s). Last edit at 08/27/2019 11:04PM by martyscarr.

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Re: Special cylinder head engineering drawing
Posted by: BobV66Vair ()
Date: August 28, 2019 07:14AM

If you took these to an AutoCad engineer or even an architects shop they could draw a new set exactly like these. Maybe better since they would be drawn in a computer and interferences could be seen. Then the sky's the limit on mods.

Just thinking out loud. I think the air cooled limit would still be a factor though. Porsche Turbo got about as much HP out of an air cooled engine, that would live, as possible. That's an awesome target though!

Bob Vinnacombe
Sandy, Oregon
1965 Corsa 140 stock
1966 Monza Soon to be race car
1968 Monza Parts for now

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Re: Special cylinder head engineering drawing
Posted by: jjohnsonjo ()
Date: August 28, 2019 07:33AM

Lets not forget Kevin's new fan. That project could solve a lot of our cooling issues.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: Special cylinder head engineering drawing
Posted by: kdrolt ()
Date: August 31, 2019 02:10PM

The intake runner looks a lot like those shown on the front-engine rwd midget cars shown in the versions of How to Hot Rod Corvair Engines (by Fisher, then Emerson).

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Re: Special cylinder head engineering drawing
Posted by: SteveInMarietta ()
Date: September 01, 2019 01:54AM

Here is another drawing, RX8000, dated 1959, which I believe is an experimental Corvair fuel injection system, but I know not how it is developmentally related to the Bill Johnson drawing or the GM Corvair FI program about which Rick quoted above. Drawing was very large but of poor quality and have been extensively Photoshopped to make portable and more legible. Thoughts....?
Steve

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Re: Special cylinder head engineering drawing
Posted by: Max Roeder ()
Date: September 01, 2019 05:44AM

Note the designer of the cylinder head is "Hildebrand" and the "Bill Thomas" in quotations with Signature Products under his name. This makes me believe Bill Thomas was using a freelance aerospace designer named Hildebrand to assist in development work. Most all air cooled aircraft engines use single cylinder heads.

Note also the specification of material/ heat treat of a 356 T6 value. The stock heads off corvairs aren't of the T6 process due to their mass. With the smaller cylinder head a T6 would work without leaving stresses internally like would be seen with the mass of the existing corvair design. The 356 is interesting because most high end aluminum castings are A356, the A denotes the higher purity of alloy. Not sure when in time the SAE recognized the A356 over the 356.

Also what is curious is the intake port runner design. There appears to be no "venturi" effect desired to speed up the air flow. The drawing being numbered "1" makes me believe this was a concept drawing and quite possibly never placed into a manufacturing scenario.

Thanks again to Steve Spilatro for his time to render a useful drawing, just like the Phoenix!

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Re: Special cylinder head engineering drawing
Posted by: CORSATURBO65 ()
Date: September 08, 2019 09:49AM

I am certain, that somewhere one there in cyberspace today, there MOST certainly is is a present day version of a "Hildebrand" that using the present day CAD design technologies, cutting edge modern casting processes, and modern far superior aluminum alloys, and then fully incorporating the known combustion chamber and port design lessons already learned and trialed by Tom Knoblach, Ray Sedman, Michael LeVeque, and others,... that simply designing a 2020 version of a completely modern standard or modular design Corvair cylinder head can not be that far out of reach.

Would you trust a truly modernized cutting edge design "signed off on" by someone like Tom Knoblach? I would. Order me some of those.

Designing and building a significantly improved and modernized Corvair cylinder head, or even an 8" wide modular cylinder head head is not rocket science. Complex, certainly it is. Impossible? Hell no. No more impossible than designing and building a modern high output air cooled lawn tractor cylinder head. Same type of design efforts, same type of manufacturing processes.

Maybe we should ask Techumseh or Briggs & Stratton to design and build it???

Once a design drawing was completed, it could be cast out of premium alloys, using lost foam process or any one of modern pressure casting processes.

A manufacturer like Briggs & Stratton, Mercury Marine, Edelbrock, or any similar job shop who casts durable, precision, small parts all of the time day in and day out could be commissioned to do it.

Once designed "on paper so to speak" the casting is simply a job shop process. This is by no means rocket science or an "impossible to do" task.

Someone design it, and you can count me in to help find a job shop to cast it, using an ultra-modern high-temperature aluminum casting alloy such as some of the newer variations made by Alcoa and others for casting high performance aluminum cylinder heads that are going to be subjected to high heat.

There are CAD design and small parts casting experts out there. Social media could help us find them.

CORSA TURBO 65
RICH

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Re: Special cylinder head engineering drawing
Date: September 10, 2019 05:46PM

Thats a good idea.
Just a couple 100k to Start. If money is no Problem,

We can manage this i agree.

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Re: Special cylinder head engineering drawing
Posted by: SteveInMarietta ()
Date: September 10, 2019 09:39PM

FYI: I also have scans of a large number of Bob Anderson CIDCO drawings of reengineered differentials, including reverse rotation. Here's a few low resolution snippets:







Steve

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