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Re: [alfa] Dead springs on Magnet Marelli advance mechanism?



Hi matt. There is a primary spring and a secondary spring. The secondary
spring shouldn't come into action until say 3500 so your description sounds
normal to me. You can substitute springs and verify the results with the use
of a timing light. The car should idle between say 5 and 8 degrees and
should not go beyond the max advance mark on the pulley which I believe is
36 degrees all though that can also differ between models. What you want is
a nice soft primary spring so the advance picks up early and a heavy
secondary spring to slow the advance curve as the revs rise. With the
marelli dizzy there is a advance slot that a pin slides in. make sure the
slot is square at the end of its travel because if you have a weak secondary
spring this slot can wear causing over advancing and melted piston landings
around the rings. It is worth playing with a few different springs if you
have a good timing light.
Cheers,
Dean
-----Original Message-----
From: Matthew Hanselman <mjhanselman@domain.elided>
To: dwc@domain.elided <dwc@domain.elided>; alfa@domain.elided <alfa@domain.elided>
Date: Friday, 18 June 2004 1:54
Subject: Re: [alfa] Dead springs on Magnet Marelli advance mechanism?


>Thanks for the replies
>
>I have a PLEX 10 system in the car, which was used in the 80-81 spiders.
>True, I don't truly know the springs are dead, but there are two different
>kinds of springs in the advance mechanism (different weigths and coil
>counts), and one of them is overstretched so it doesn't even engage in the
>first 1/4" of travel of the weight.  The rest of the SPICA is still in
>place.
>
>Oh well.  The car still runs pretty well when it's wide open... :)
>
>- Matt
>
>>From: "Dean W. Cains" <dwc@domain.elided>
>>To: alfa@domain.elided
>>CC: "Matthew Hanselman" <mjhanselman@domain.elided>
>>Subject: Re: [alfa] Dead springs on Magnet Marelli advance mechanism?
>>Date: Wed, 16 Jun 2004 22:19:23 -0400
>>
>>Hi Matt:
>>
>>I'm not sure what criteria you're using to determine the condition of the
>>advance springs, but a fair amount of free play is built into their
>>mechanism.  The only proper way to check your timing, and advance/retard
>>with rpm changes, is with a timing light (preferably an "advance" timing
>>light with a dial indicator or digital display).  Tried that?  Assuming
>>that you have, there are other considerations, and given the choice
between
>>having the timing set properly at 5000 rpm's or idle. most of us would
>>choose the former, and that's not necessarily something that needs
>>intervention.  Further, if the distributor is in fact from an '80 Spica
>>Spider, you'd be better off with the original distributor, with regards to
>>having an advance curve that suits the '73 Spica engine.  Finally, I'm
sure
>>most of us are unsure what distributor you're speaking about, since all
the
>>Spica cars used Marelli distributors, although among the later cars, some
>>had dual sets of points and some were breakerless.  Do you have a model
>>number?  Does your '73 have its Spica system still in place?
>
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