<VV> Corvair Cylinder Heads

[RoboMan91324 at aol.com]

Gary,
 
Welcome back to Corvairs.
 
First, as far as towing a vehicle, if you are towing a Corvair  on a 
trailer the issues are those that have to do with your tow vehicle and  weight 
distribution on the trailer.  Remember that the Corvair has the  engine weight 
in the back.  If you are going to flat tow or tow on a dolly,  there are 
issues with the transaxle.  I do not want to reopen this train  unless you 
intend to tow with the drive wheels on the ground.
 
Regarding your desire to make new Corvair heads, are you going  to merely 
reproduce the heads as they exist today (with the interchangeable  intakes) 
or come up with a new combustion chamber design?  There are  literally dozens 
of head part numbers.  Some have very little difference  between them and 
some have very significant differences.  In any case,  there are significant 
differences other than two intake ports vs. four  intake ports (one and two 
per head.)  Some heads are so common and low  performance that you do not 
want to waste your time looking at them to  reproduce while others may be 
desirable to replicate.  However, even  the 140 HP heads (arguably the most rare 
and desirable) are available at a  price.  Only you can determine what your 
development and manufacturing  costs are compared to the purchase of good 
used or even NOS parts.
 
If you are considering a whole new design, if you are not  contacted by 
Smitty very soon, I would be very surprised.  Smitty has been  investigating a 
head redesign for some time.  I don't know the present  status.  I don't 
have his email address handy right now but I am sure  others do.  Some things 
you may want to consider ......
 
1.  Deeper valve seats.  Dropped valve seats are a  problem with Corvair 
heads especially in the 140 HP and the turbo applications  which have bigger 
diameter valves and higher operating temperatures  respectively.  The 
interference fit of the seats to the heads are beginning  to fail in these older 
heads especially in high performance applications or when  overheated.
 
2.  Early model (EM) heads have smaller diameter  seats for the cylinders 
while the late models (LM) heads are larger
 
3.  Up until 1965 (I think) the bolts used to attach the  sheet metal to 
the heads are smaller than those in 1966 and later.
 
4.  The 140 heads have two intake ports each, larger  valves and larger 
exhaust ports.  This will need to be a unique  design.  
 
5.  Are you going to have just the two intake designs or  will your intakes 
be able to handle other after market carbs?
 
6.  The above is only touching on the surface of the  variety of 
considerations you face.  On the assumption that you use the  folks here on Virtual 
Vairs as a resource (highly recommended) as you progress with this project, 
you will have many opinions offered on  every design aspect.  Even individuals 
with significant expertise may have  strongly differing opinions on a given 
subject.  Brace  yourself.
 
Welcome and good luck,
 
Doc
 
1960 Corvette, 1961 Rampside, 1962 Rampside, 1964 Spyder  coupe, 1965 
Greenbrier, 1966 Canadian Corsa turbo coupe, 1967 Nova SS, 1968  Camaro ragtop

~~~~~~~~~~~~~~~~~~~~~~~~
 
In a message dated 4/15/2011 9:00:49 A.M. Pacific Daylight Time,  
virtualvairs-request at corvair.org writes:

Message:  1
Date: Thu, 14 Apr 2011 23:13:29 -0400
From: Gary Rockwell  <cordax1964 at gmail.com>
Subject: <VV> Corvair Cylinder  Heads
To: virtualvairs at corvair.org
Message-ID:  <BANLkTi=vXuurHoVaMxMH3RbYzg_bc_Huvg at mail.gmail.com>
Content-Type:  text/plain; charset=ISO-8859-1

I am looking to get back into  Corvairs.  I have a 1974 GMC Motorhome
and would like to ideally get a  1967 Corvair Convertible (4 speed) to
make as my tow car.

I have  been making intake manifolds for the guys in the GMC  Club:

http://www.bdub.net/grockwell/

I would like to start  making aluminum cylinder heads for the Corvair
next.  I would  appreciate any input you may have on making
improvements to the cylinder  heads.  As a minimum I will make the
intake manifolds interchangable  so you may select how many carburetors
you want, etc.

Unless you  have a lot of money to spend, it takes a very long time for
these projects  to complete.  So I would appreciate any inpout and also
your patience  until we have them cast and machined.

If anyone near Dayton, OH has an  old cylinder head I can by cheap or
borrow to measure from please let me  know