Mark,
    Same here.  I runa pertronix on all my air-cooled, and have the points and condenser in the tool box.  I like the low maintenence aspect, and the consistency of breakerless ignition.  However, in a pinch, I could put the points on.

Adam Puzerewski
81 westy
74 beetle
-----Original Message-----
    From: Mark Rokus <marokus@VOYAGER.NET>
    To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
    Date: Saturday, May 13, 2000 11:33 PM
    Subject: Re: [VANAGON] dwell
    
    
    To add even more trivia to a beat to death subject:
    Yes, Pertronix are Hall effect based.  A hall sensor turns on based on the strength of the magnetic field that they see, thus, it is logical to conclude that you can effect the dwell by changing the distance from the collar (with the magnets in it) and the sensor.  ie... the closer the pick-up is to the collar (magnets) , the longer the sensor will see it.  Obviously, if you get too much of a gap, the pulse will be shorter.    
    
    Personal experience: Don't get you hand anywhere near the business side of one of these (coil output).  Not only does the module decide when to fire the coil, it gives it a sustained spark. It hurts lots more than when you get hit by points.  I ran one in a beetle that I circle track raced for years and it brought home more than one trophe.  It later went into a '73 bus and ran fine.  In case it matters, I also carried a set of points and a condenser in the bus just in case. 
     Mark Rokus
    '87 Syncro (wifie's)
    '87 Syncro Westy: Mine :-)  
    '81 Westy
    '82 Diesel Rabbit
    '72 Karmann Ghia 
    ----- Original Message ----- 
        From: jeff crane 
        To: vanagon@GERRY.VANAGON.COM 
        Sent: Saturday, May 13, 2000 10:54 PM
        Subject: dwell
        
        
        Yes dwell angle is  still a factor in  transistorized ignitions.  It is no longer adjustable but through software it is possible in distributorless ignitions,   but  no the service tech cannot do so. 
         Dwell is  expressed in  degrees of distributor shaft rotation.   30*dwell on an eight cylinder engine  would leave  120*  of  cumulative rotation for the coil to  be off charge and therefore cooling somewhat. 45* on a four cylinder engine would  leave 180* to cool,  and 180* to charge the coil cumulatively. Simply because the distributor shaft rotates 360* of course.  If you have a transistorized ignition, breakerless whatever, you  can still measure the dwell angle.  If the system is weak  chances are you will find a  shorter dwell angle when you test it.  I have done this and I know it works.  In fact,  transistorized ignitions can and do have variable dwell periods factored  into the circuitry  on some  applications. In reality the hall effect sensor is simply a switch and not the conductor that all current must pass  to charge the coil and this  leaves  you many possibilities. 
          To understand this best it is best to realize that dwell exists even in distributorless ignitions, though it is   often ignored, it is  a percentage of  time in a given engine revolution.  That doesn't matter but that it is important to realize that   without contact points you do still have a dwell angle.
        
        

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