180 Vacuum Advance Re: <VV> distributors

[Duane, Jim (US SSA)]

Hi Frank.
    True, and the "down side" is lots of advance at idle.  I haven't
researched the availability of the Nash/Vette throttle body (I
understand the YH was also used on tractors) and should do that
first...Grant?  Not really a problem for me, but others who have
attempted to "smoothly launch" my car find it difficult.  I thought abut
the idle switch and switched vacuum, but the Electrical Engineer in me
wanted to try something different.  
    In addition to a Pertronix I, I also have installed an EKE that is
ancient transistor technology, but works.  It retards the timing,
progressively, with each impulse from the knock sensor, until a max of
10 degrees.  Sooo, I designed (haven't built yet) a missing pulse
detector that sits on the pertronix output to the EKE and intend to have
it adjusted to trigger at about 1100 RPM.  The missing pulse detector's
output pulses are wired to the knock sensor wire.  Should work.  I'll
build it, er, ah, some day...
 
Jim "procrastination" Duane
 

JED


 

  _____  

From: FrankCB at aol.com [mailto:FrankCB at aol.com] 
Sent: Thursday, June 29, 2006 5:14 PM
To: Duane, Jim (US SSA); hyarnell1 at earthlink.net; ron67ran at hotmail.com;
virtualvairs at corvair.org
Subject: 180 Vacuum Advance Re: <VV> distributors


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