[TR] TR4A - Breakdown Update - Dizzy Replaced

[Randall]

>  I've heard rumor 
> of advancing the
> wheel until the engine begins to "ping" (premature detonation?), then
> retarding until it stops.  Does this really give you the best advance?

Best achievable by ordinary mortals, yes.  You could probably do better with
a dyno, though.

> 2. When the mechanical advance kicks in, it does rattle a 
> bit, but nothing
> like the Pertronix.  What can I do to cure this, if anything?

I'm not sure I understand this statement; but it seems like you are
describing pinging (aka ignition knock, aka detonation, aka premature
ignition) from too much advance.  The advance itself should be totally
silent, all you should really hear is the exhaust note rising in pitch.
Anything that "rattles" is a Bad Thing.

Since you've had this problem with two distributors now, I'm wondering if
perhaps your compression ratio has been increased (perhaps by oversize
liners or by modifying the head); or you are running really low grade fuel.

While it would be best to isolate the cause, you should retard the spark now
to stop the detonation.  If not, there will likely be one of these in your
future
http://goo.gl/54z9U

-- Randall