[alfa] Re: distributor advance curve and timing

[Jim Neill <papajam@xxxxxxxxxxxxx>]

Vangelis asked;

>I was hoping that someone in the list can explain this
>mystery to me.  According to the alfa shop manual as
>well as Alfa Ricambi's catalog, most distributors
>fitted to the 2lt engines have a max mechanical
>advance of at most 18deg (my marelli-plex has a max
>advance of 12deg) that is reached near or before
>2500rpm.  Therefore, in order to get a max advance of
>about 38deg as suggested by Wes' SPICA manual, the
>static advance should be about 20deg advanced...
>(20+18=38)... However, static timing is supposed to be
>somewhere near 5deg... What gives???

Many times, distributor specs are given relative to the distributor, not the engine. Since the dist turns one half of engine speed, multiply the dist specs by 2. So a dist spec of 18 deg @ 2500 rpm equates to 36 deg @ 5000 rpm at the crank.

Jim
68 1750 GTV
papajam@domain.elided
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