I'll take a stab at this, someone jump in and correct me if I'm wrong. My
experience on 1500's has been 1979's in California Emissions trim.
Basically speaking, the distributors on the 1500's have very little
mechanical advance available because advance = higher NOX emissions. I
think it is in the neighborhood of 12-14 degrees mechanical advance by
2500-3000 RPM. For optimum performance without regard to emissions, total
advance should be around 32-34 degrees. (I'll assume you are not running
vacuum advance or retard) Therefore, a static timing of 22 degrees, plus
the mechanical advance of 12 more would yield the ideal 32 degrees. The
draw backs of this much static advance is the possibility for dieseling, and
hard starting. I have found these two problems to crop up before pinging.
If they do, back up the timing one degree at a time, until the symptoms
stop.
A nice solution is to fit a distributor from an A or B series MG that has
more mechanical advance available. You can then run less initial advance
with the same combined advance available at higher Rpm's. Adapting vacuum
advance helps as well. The 48 state MGB distributor is a good choice. it
has 22 degrees (again from memory, could be off a pinch) of mechanical
advance available, and 6 degrees of vacuum advance available. I have this
distributor on my 1275 and have added a vacuum port to the DCOE 40 just
infront of the throttle plate. At idle, no vacuum, at part throttle, high
vacuum, wide open low vacuum. I have the initial timing set at 6 degrees,
which makes for easy starting, but total advance while cruising at 3000 RPM
and above is 34 degrees.
Hope this helps.
David Riker
74 Midget
63 Falcon
70 Torino
http://home.pacbell.net/davriker
----- Original Message -----
From "Brent Wolf" <wolfbj at prodigy.net>
To: "Spridgets" <spridgets@autox.team.net>
Sent: Saturday, February 02, 2002 9:39 PM
Subject: 1500 Weber and Timing
> Under fine tuning, it says to reset the timing to match the additional
power
> output. It says to reset the ignition timing to 22-25 BTDC at 900-1000
> rpm.. I am a little leery here. This entire instruction is titled for an
> MGB. I don't know what the original ign. timing was. My 1500s original
> timing was either 2 ATDC or 10 BTDC (depending on where you read).
>
> I have adjusted my timing to 16 BTDC and I am impressed with the
> performance, etc. My question - Is anyone running around with a1500 set at
> 22-25 BTDC? What kind of indications should I expect if I advance my
timing
> to far? Overheating??? Ping or knock?? (none yet) Run on (None Yet)
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