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Re: Dizzy Vacuum Advance bad?

To: Christian Stanton <cstanton@pixley.com>
Subject: Re: Dizzy Vacuum Advance bad?
From: Trevor Boicey <tboicey@brit.ca>
Date: Thu, 29 Jul 1999 23:30:52 -0400
Cc: Spridgets@autox.team.net
Organization: BRIT Inc.
References: <s7a04d5f.096@pixley.com>
Reply-to: Trevor Boicey <tboicey@brit.ca>
Sender: owner-spridgets@autox.team.net
Christian Stanton wrote:
> The Dizzy is an EID type converted with an unknown type of
> external Electronic Ignition.  The car is a '78 California
> but the engine is from a Tr***ph Spitfire. (I haven't
> exactly determined the year of the engine yet).

  Sounds like you stole my car, I had better check the
driveway. ;>

> There is the chopper (slotted disk) which is friction fit on the shaft.  There
> is no descernable indexing.  How do I align it relative to the rotor?  I
> looked at an older dizzy I had from an MGB and eyeballed the slots to
> coorespond to the high spots on the mechanically cammed shaft.  Is
> this right? (it runs like this).

  Turn the engine until it was about 20 degrees BTDC, this
is in the middle of where your sparks will happen. Make it so
it's at cylinder #1 firing stroke. (one or both valves will
be open on #4 cylinder, take off the valve cover if you
are unsure)

  Install the rotor, and figure out where it is pointing. Turn
the distributor until the rotor points at a plug lead. Any
lead will do, that will be where #1 spark plug wire will
go. (then it's 1-3-4-2 counter clockwise from there)

  Take the spark plug wire out of the center of the distibutor cap,
and put it somewhere near metal so you can see it spark. Turn
on the ignition, and slide a piece of paper between the electronic
sensor and pull it out, you should see the spark jump from the
wire to the metal. What you are trying to determine is
"does the unit fire the spark when the light beam is interrupted,
or when it is re-established". 

  Then, have the chopper installed, and open the little screw
that holds the opto unit in. Move the opto unit around
until it is such that, with the chopper turning counter
clockwise, the light beam is either just broken or just
returning, depending on the above test. Basically, set it
so the spark will fire when the rotor is there.

  The car should start here. Then fine tune it normally
using a timing light and rotating the distributor. As long
as you don't have to move the distributor too far, the
rotor still should line up to the terminal in the cap.

> Are the vacuum advance units that fragile?

  They don't like solvents...

-- 
Trevor Boicey, P. Eng.
Ottawa, Canada, tboicey@brit.ca
ICQ #17432933 http://www.brit.ca/~tboicey/
"Wanna see me comb my hair really fast?" - Johnny Bravo

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