<VV> Single Carburetor

[Shelrockbored at aol.com]

This was my point when I said that there will be many challenges.  I  am 
not a carburetor expert so if you have gotten it to work on other automobiles  
and feel that it can be done on a Corvair, that's great.  As has been  
bourne out in this thread though it is not a simple bolt up and  adjustment.  
For a single carburetor (2 barrel or 4 barrel - 2 barrel is  rare)  to work on 
a Corvair one must find a way to apply heat to it.   This is a MUST in all 
cases and as I've learned from this thread, have found out  why and how it 
is done on an in-line engine.  
 
If I were going to effect this installation in a Corvair (I have no plans  
to do so), I would use the modified intake manifold (as described by below  
by Mike) and duct hot oil to it to keep it warm.  
 
Hope it works out for you.  Good Luck.
 
Steve Sassi
 
 
In a message dated 4/23/2013 12:29:13 A.M. Eastern Standard Time,  
mmccrae6 at cox.net writes:

This was  my letter to “Corsa “ RE: use of single carbs....perhaps there 
are some words  in there that may help with your problem....
Regards, Mike  McCrae

09/08/2010



Dear Larry,

I found the four  barrel manifold article interesting, but what always gets 
me is that no one,  VW, GM, etc. has ever made a remote carb work well 
without applying heat to  the manifold. Remember the Grand National....they had 
to plumb the turbo  intake manifold to accept heated water from the 
radiator. There is a very  simple answer which I provide, and solves these problems. 
The bottom of the  four barrel intake manifold is machined away, and an 
aluminum box is  fabricated and tig welded in place to carry engine oil. The 
oil comes from the  oil filter log which I machine off....A remote filter is 
then used on the  return line from the heater box. This system not only heats 
the plenum, it  cools the oil as well. The oil leaving the manifold is 
generally 10-12*  cooler.

Exhaust could be used for heat if one wants to replumb an AIR  exhaust 
manifold. The perfect example is the single carburetor V W engine.  

All carburetors become refrigeration systems, due to the Fuel/Air  (F/A) 
compression in the venturi and idle systems and later expansion in the  
plenum. All modern engines compensate for this phenomenon by locating the  
carburetors over the oil valley in a V-8-6, or over an exhaust manifold in  inline 
engines. Corvair engineers wisely mated the intake manifolds directly  to 
the head, keeping the F/A mixture warm, and in suspension.  The lack  of heat 
to the remote 4-barrel manifolds we use allows the F/A mixture to  condense 
on the sides of the frozen plenum, creating a very lean situation,  and 
resultant hesitation (lean skips). Winter operation becomes almost  impossible 
due to carburetor ice formation with resultant frozen idle  circuits. Most 
folks compensate for the problem by using the 50 cc accelerator  pump and 
fire-hose nozzles. The result being poor gas mileage and extreme  dilution of 
the oil at the top compression ring. With my system, one can use  the stock 
Holley accelerator pump and normal nozzles.

My suggestion for  initial carburetor settings in the Holley 390, 4160 
series is as  follows:



Stock accelerator pump (NOT the 50cc)

.031  Accelerator pump nozzles

.057 primary jets

.059 Secondary plate  jets

75 power valve

Electric choke

Purple secondary  diaphragm springs





Best wishes, Mike  McCrae

619-466-0014




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