180 Vacuum Advance Re: <VV> distributors

[FrankCB at aol.com]

Jim,
    I think the only problem with the Dale vacuum  advance/pressure retard is 
that is uses MANIFOLD vacuum for the  advance.  All NA Corvairs use a PORTED 
vacuum source in the carb so that  there is NO vacuum advance at idle.  With 
manifold vacuum at idle, you have  full vacuum advance at idle and as soon as 
you accelerate off idle speed, the  timing advance takes a big drop, not too 
good for off the line acceleration  and throttle response.  There are at least 2 
solutions to  this.  The most obvious one is to switch out the 150/160 
throttle body of  the YH (which is separate from the rest of the carb) with a 
similar YH throttle  body from a NA early Corvette or Nash or ?  Those throttle 
bodies have a  vacuum advance port just like on the Corvair Rochester carbs.  But 
you have  to find that non-Corvair YH throttle body.  
    Another way is to install a microswitch on the  throttle linkage that 
controls a vacuum solenoid valve you install in the  manifold vacuum line.  
Adjust the microswitch so that the vacuum to the  distributor is shut off at idle 
and turns on as soon as the throttle goes off  idle.  I think Ray Sedman has a 
kit for this setup.
    Frank "try it, you'll like it" Burkhard
 
In a message dated 6/26/2006 12:57:36 PM Eastern Standard Time,  
Jim.Duane at it.BAESystems.com writes:

Ah, so  true.  An "alternative" is to re-curve and put in a  vacuum
advance.  Actually, on my 180, the Dale vacuum/advance and  stock turbo
distributor are just "ducky" in non-boost driving, but not  optimal, like
this "ducky" weather on the east coast...
JED

Jim  Duane
'66 180 Corsa CVT