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Re: Billet cylinder heads UPDATE!!
Posted by: REM654DPG ()
Date: January 13, 2020 09:27PM

If you lay a set of heads on the bench and look at the chamber side you can see this offset in the lower stud hole and this is what prompted me to come up with this print. The case has the same offset and you can see it just the same with a visual inspection. Being that I did not have the factory print I figured the reverse engineering process would actually be more accurate for what I was doing.

Just to clear up some of the doubt, the dimensions on my print are a compilation of measuring 5 cases and 5 heads - which were on average +/- .005 of each other - and then dividing all the numbers to sum up the average number. I did this measuring on my EZ-Trak mill which has a 4 decimal place DRO, precision lead screws and with a Drake CO-Ax. I needed these actual dimensions to make my new torque plate assembly and wanted to make sure the dimensions mirrored the actual case and heads. I’ll attach a few pictures just for conversation sake.

Thanks for posting the factory print as it confirms the accuracy of my physical measurements. If you do the math from the dimensions shown using GMs tolerances given of +/- .010 on the X&Y and only a .006 spread on the lower rt studs X location, my average numbers show that what we actually have is within the factory specs and that this offset anomaly was purposely designed in from GM for who knows what or why.

Regan Metcalf
Portland, OR

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Re: Billet cylinder heads UPDATE!!
Posted by: John Luscinski ()
Date: January 14, 2020 04:13AM

Reagan just curious, Where did you get the large piece of Aluminum?

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Re: Billet cylinder heads UPDATE!!
Posted by: vairmech ()
Date: January 14, 2020 04:30AM

The only issue with reverse engineering is if something is off but within tolerance, then you make a print from parts that are off but within tolerance and then put tolerances in again, suddenly you have a piece that will be non standard if the piece is made at the limit of the tolerances of the copy.

It then becomes a copy of a copy of a copy and we all know that the quality of the copy down the line is not as good as the original.

BTW, I'm NOT bashing you Reagan.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

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Re: Billet cylinder heads UPDATE!!
Posted by: jjohnsonjo ()
Date: January 14, 2020 05:48AM

Did GM ever use torque plates when they made them new?

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: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: January 14, 2020 08:04AM

GM wouldn't have used torque plates. They are more of a "lets make this as close to perfect as possible" performance thing, rather than a "lets make a lot of these and make a profit." thing.

Beautiful job though!



Edited 1 time(s). Last edit at 01/14/2020 08:05AM by racingguy2.

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Re: Billet cylinder heads UPDATE!!
Posted by: wv-geo ()
Date: January 14, 2020 05:31PM

The bottom two stud holes are offset from the top two so that the bottom two are closer to the valves and could be used as the mounting points for the rockers.

Dan Stark
Hurricane, WV

1961 Lakewood 500, 80HP, PG
1964 Corvair 500 Coupe, 140HP, 4spd (Christine)
1965 Mustang Coupe, 6cyl, 3spd

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Re: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: January 14, 2020 06:59PM

On the heads, the plan is to rough machine, heat treat, age, then finish machine so that when I finish the surface that the cylinders seat against I can hold them all within .0005 height or better.

Anybody know how parallel and consistent height the cylinder jugs are?
Or for that matter, how consistent height the shoulders in the case are?

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Re: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: January 15, 2020 03:44PM

Finally got our electric installation approved this afternoon! Of course it was another $1000 for a second electrician, but it's done! The electric company is scheduled to connect on the 22nd, but at least it's progress! Meanwhile, we've had plenty of time to organize, so the shop is looking really nice!

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Re: Billet cylinder heads UPDATE!!
Posted by: MattNall ()
Date: January 15, 2020 03:49PM

Hate to hear what you've spent so far... and not a single chip cut!

Just like building a house!

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: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: March 29, 2020 08:57PM

Progress! We've had the shop up and running for a couple weeks now, and are catching up on the paying work! Right now I'm running some prototype medical parts for the current crisis, then I may be making a set of molds, but then on to something cool and much anticipated! I've got material, tooling, and programs ready to go for my first set of billet Corvair heads, and plan to be running them soon!

Right now, my biz partner and I are working opposite shifts, avoiding each other with the excuse of "social distancing", so we are actually getting a lot done!

Also bought more equipment since the last update. Bought a Citizen L20 CNC Swiss lathe, a nice Atlas-Copco screw compressor, and a few other basics.

Eric
Plymouth, Michigan
74 Kelmark GT (Mid engine Corvair 140)
02 Maserati CambioCorsa Spyder
06 Porsche Cayenne
89 Jaguar XJS 12
86 Alfa Romeo Graduate (7200 miles!)
1902 Curved dash Olds
70 Fiberfab Avenger
57 Ford Custom 300 (factory 312Y)
80 Mercedes-Benz 450SL
05 Audi TT
Cylinder head and valvetrain engineer, PhD Nuclear Engineer
Originator of strange ideas and over-complicated solutions!

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Re: Billet cylinder heads UPDATE!!
Posted by: REM654DPG ()
Date: March 29, 2020 11:07PM

That's great news Eric and I'm glad you are staying busy during this shut down. Nice set up you have too with all the new equipment and I bet you wish you could be making only Corvair parts with it all. I wish you well

Regan Metcalf
Portland, OR

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Re: Billet cylinder heads UPDATE!!
Posted by: Ron62 ()
Date: March 30, 2020 08:11AM

Will you be making stock replacement heads for the street or only modified for the racers..

Ron

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Re: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: March 30, 2020 08:25AM

Ron, there will be a street performance version.

Eric
Plymouth, Michigan
74 Kelmark GT (Mid engine Corvair 140)
02 Maserati CambioCorsa Spyder
06 Porsche Cayenne
89 Jaguar XJS 12
86 Alfa Romeo Graduate (7200 miles!)
1902 Curved dash Olds
70 Fiberfab Avenger
57 Ford Custom 300 (factory 312Y)
80 Mercedes-Benz 450SL
05 Audi TT
Cylinder head and valvetrain engineer, PhD Nuclear Engineer
Originator of strange ideas and over-complicated solutions!

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Re: Billet cylinder heads UPDATE!!
Posted by: Ron62 ()
Date: March 30, 2020 01:12PM

Excellent !! Looking forward to the progress.

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Re: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: April 11, 2020 08:57PM

I've got everything ready to cut the first set of cylinder heads, as soon as we are allowed to go back to work! We were still running, just working opposite shifts, behind a locked door, but someone actually called the police on us. The cop was nice about it, (even though I answered the door with a chem respirator on, and sprayed the door with lysol!) but advised us to shut down, or only have my partner working. (He's a world class machinist, but just learning cnc, so we are taking a break and catching up on car projects.) The shop is on the same property as his house, and I live 20 miles away.

So, I've got the material, design, tools and programs.
We've already named the tool for cutting the fins "Eric's spinning wheel of death" spinning smiley sticking its tongue out
Picture a 5" carbide circular saw blade mounted on a 1" shank in a CNC mill!

Probably the biggest update is that I've been discussing an agreement with Ken Hand for valve work and testing!

Eric
Plymouth, Michigan
74 Kelmark GT (Mid engine Corvair 140)
02 Maserati CambioCorsa Spyder
06 Porsche Cayenne
89 Jaguar XJS 12
86 Alfa Romeo Graduate (7200 miles!)
1902 Curved dash Olds
70 Fiberfab Avenger
57 Ford Custom 300 (factory 312Y)
80 Mercedes-Benz 450SL
05 Audi TT
Cylinder head and valvetrain engineer, PhD Nuclear Engineer
Originator of strange ideas and over-complicated solutions!

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Re: Billet cylinder heads UPDATE!!
Posted by: doug6423 ()
Date: April 12, 2020 03:34PM

Thanks for the update! Looking forward to the finished product.

Doug
65 Monza
Cincy, OH

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Re: Billet cylinder heads UPDATE!!
Posted by: v8vair ()
Date: April 13, 2020 06:13AM

wouldn't it be advisable to find someone with a superflow flow bench for final port work and valve work, A true Cylinder head racing shop like Kent Ford at Racing systems inc ? Who has already brought the Corvair head to the next level with some fast Racers . Or Ray Clay Clayton that has a engine dyno just for corvair motors and a real Flow bench ?I never realized how much more flow can be gained by a proper racing valve job with the depth of the valve being place properly.As you would know a lot to be learned with a real flow bench

1965 Crown V8 Racer
1964 Bill Thomas Monza Replica Racer
1964 Spyder Street Car
1979 Mazda RX7

Mike Levine



Edited 1 time(s). Last edit at 04/13/2020 06:17AM by v8vair.

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Re: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: April 13, 2020 02:14PM

Mike, I'll do the flow testing and tuning, but I expect it to be very close. I've done a lot of comparative research on flowbenches and flow vs. velocity tuning. SuperFlow sucks (joke intended). They measure pressure drop at a given flow, not flow at a given depression. I have access to a couple that I've compared. Including the wet flow bench that was Smokey Yunick's and a 2500cfm @28" unit at Thermolift that I built. Research showed that the SuperFlow numbers were inflated even on RCR's $250k unit, and repeating the same tests varied by as much as 5%. In contrast, Audie's Flow Quik was the most consistent and accurate with test results varying less than 1% over multiple tests. (And since it calibrates to an orifice plate every time, accuracy is a scientific process.) I've made a deal to acquire a bench, that I'll probably retrofit with a Flow Quik unit.

Ah, just scrolled up and re-read! Ken Hand will likely be doing the real world testing on his race car. He's a genuine corvair genius, a true gentleman, and is less than an hour away from me.

Yes, I agree. Valve and seat geometry is quite critical! For the all out race version, I'll be sourcing valves and seats from Trick Titanium, but they are my own design to match the airflow of these heads. Ti intakes, Inconel exhaust. (I used to work there as their engineer.) About $700/set.

Teaser of the day: Computational Flow Dynamics estimate intake flow at 200cfm at .5". Needless to say, the intake is a little bigger than stock!

Eric
Plymouth, Michigan
74 Kelmark GT (Mid engine Corvair 140)
02 Maserati CambioCorsa Spyder
06 Porsche Cayenne
89 Jaguar XJS 12
86 Alfa Romeo Graduate (7200 miles!)
1902 Curved dash Olds
70 Fiberfab Avenger
57 Ford Custom 300 (factory 312Y)
80 Mercedes-Benz 450SL
05 Audi TT
Cylinder head and valvetrain engineer, PhD Nuclear Engineer
Originator of strange ideas and over-complicated solutions!

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Re: Billet cylinder heads UPDATE!!
Posted by: v8vair ()
Date: April 13, 2020 03:07PM

Awesome, looks like you and ken have all the bases covered smiling smiley
Don't need my input, good luck

1965 Crown V8 Racer
1964 Bill Thomas Monza Replica Racer
1964 Spyder Street Car
1979 Mazda RX7

Mike Levine

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Re: Billet cylinder heads UPDATE!!
Posted by: racingguy2 ()
Date: April 13, 2020 03:16PM

Mike, I'll take all the input I can get please!!!!
While I've been designing race cylinder heads for about 20 years, I'm still a Corvair newbie, so I've been searching all the issues I can solve and incorporating them. This thread has provided a lot of Corvair specific insights that I wasn't aware of. Thank you and everyone else for the questions, input and ideas!

Eric
Plymouth, Michigan
74 Kelmark GT (Mid engine Corvair 140)
02 Maserati CambioCorsa Spyder
06 Porsche Cayenne
89 Jaguar XJS 12
86 Alfa Romeo Graduate (7200 miles!)
1902 Curved dash Olds
70 Fiberfab Avenger
57 Ford Custom 300 (factory 312Y)
80 Mercedes-Benz 450SL
05 Audi TT
Cylinder head and valvetrain engineer, PhD Nuclear Engineer
Originator of strange ideas and over-complicated solutions!

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Current Page: 6 of 7


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