RE: alfa-digest V7 #1156 Spica "Improvements"

["Brian Shorey" <bshorey@domain.elided>]

> I have a sincere request regarding the oft-mentioned post-production
> "improvements" to the Spica fuel distribution pump attributed to Wes
> Ingram (and others).
>
> I would appreciate receiving detailed definitions and descriptions with
> documentation of these "improvements" from anyone involved so I can pass
> them along to Dario Radaelli (the developer of the system) for his
> comments.

i'll try.

for the non-ingram mods, i know of two.  the first was done by ven fonte,
although i don't know if he thought it up himself or was told by others.
basically it involved stretching or replacing with a looser one) the spring
in the section of the pump that holds the centrifugal ball.  the idea is to
allow the ball to increase its orbit faster, which slides the 3d cam
sideways (or lengthwise) faster, which pumps more fuel faster...

this mod certainly seems to enhance the perceived responsiveness of the
engine.  the first spider i owned, purchased from ven, had this mod (among
others) and would eagerly pull to 7500 rpm and beyond.

the other mod i know of was done by fred dimatteo.  it involved adding some
external plumbing to lubricate the rear section of the pump that apparently
isn't well lubricated under harsh circumstances.  this mod is described in
detail in the spica notes that the club offers.

now, on to what wes ingram provides..

wes provides two basic pumps - a street pump and a high performance pump.

the street pump is 'simply' a rebuild, to much tighter tolerances than
original, of a stock pump.  wes told me at one point that even the
relatively low mileage pumps that he's tested had variances of 10% - 40%
between cylinders.  the ingram street pumps are all well within 10% of each
other (wes targets 0% tolerance).  wes states that a street pump on a stock,
blueprinted motor with euro cams will deliver 10 - 15 additional horsepower.

the high performance pump is the street pump with a modified cam.  wes does
not recommend this pump for a street motor, the motor has to be fairly
heavily modified to take advantage of the high performance pump.

for the record, *my* rendition of the ultimate gtv ('71 of course) has a
stock 1750, balanced, with euro cams, very mild porting (just a clean up),
and an ingram street pump.  if it wasn't going to be primarily a street car
i'd lighten the flywheel a bit.  wes tells me to expect 155 hp with that
setup.  with a gear-lightened box by tom sahines, i'm looking forward to a
very enjoyable ride.

> I'll refrain from making my own.....

personally i'd love to hear of your experiences with the spica pump (and all
things alfa).  i was still a youngster in grade school back when you were
making huge technical contributions to the club, and i have yet to find the
entire alfa owner collection at a reasonable price.  even the benson spica
stuff was before my time, however the dimatteo/hertzman spica compilation
has made all of that information readily accessible.

fwiw,

bs

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