Distributor curves

[alfacybersite <acs@domain.elided>]

In #1262 Bill Sinclair feels cheated out of 'curve' on his AR Ricambi's
electronic ignition installed in his 1600 Duetto: "If I set it  as
described above (static method), however, it was somewhat hard to
start.  I had to find a compromise point about midway.  Based on some of
the comments in this thread, it seems that I need to find out what is
physically limiting the travel of the advance weights and try to give
them a little more room to travel.  Am I inviting disaster here or is
this something that could be accomplished without sophisticated
equipment?  It runs pretty good right now but I feel like I'm being
cheated out of some of my top end power."

In #1263 Norm Riffle suggests: "...the Kartamalakis book goes into some
detail
about modifying the distributor most importantly, shows how to attach a
protrator to get an accurate measurement of the advance curve."

********

To repeat Dean Cains' remark regarding modifying the advance springs, it
won't change the total advance. I just re-read the ignition section of
Kartalamakis' book. There's good information in there especially the
four items which have an effect on advance requirements.

Since Bill's system is based on a modified Bosch distributor, possibly
modifying as Kartalamakis outlines might help. However, all that will
happen is he will be 'speeding up' the advance which is already steeper
than a MarelliPlex. I base this on the graph in the (vintage) Ricambi
catalog which shows both the Ricambi and MarelliPlex's curves.

I just pulled apart a Bosch 0231 178 006 distributor and assume this is
the one Ricambi used. There are arms which limit the amount the weights
move. They could be bent or ground down, but imagine you might well be
traveling down a dark and winding road.

I strongly suspect someone out there (Tom Sahines) probably has a darn
good idea why we aren't getting the full 'range' of advance from our
systems. Tom did email me and said what most other's have said is to set
the timing light to read on M (maximum advance).

In the case of the MarelliPlex, one would have to grind off metal on the
weights so they could open farther. Now, would they then begin hitting
the sides and would losing weight cause them to not open as fast??

While I didn't spend lots of time, I advanced the distributor on my car,
took a reading and it fell about 5 degrees short of M. Then I advanced
it some more and it still fell about 5 degrees short. Possibly I didn't
rev the engine enough or...? I left it and will drive it like this for
awhile. Obviously I've had to bring the idle down considerably. Even
though, I'm still a big believer in plug checks and seat-of-the pants
feeling as to how well the engine is responding.

Still claim knowledge of electricity is a black art.

Biba
Irwindale, CA USA
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