Re: HEI vs low voltage ignition

["turbodmc3113" <turbodmc@xxxx>]

Hi Bill,

Part of your post is misleading, at least the way I read it and I 
wanted to clarify something for those following this thread. 

A coil dose not store a charge like a capacitor. A large capacitor 
can store a charge (almost like a battery) and discharge even with 
the device turned off days weeks even months later.

A coil does build up a magnetic field; it is when the power going to 
the coil is turned off that the coil creates High voltage by virtue 
of the magnetic field collapsing.
This happens because a coil will resist an instantaneous change in 
current and when the current flow is stopped, the magnetic field 
collapses and tries to maintain current flow.
The net result is that a voltage (a high voltage) is produced.

Once the power is turned off to the coil and the field has collapsed 
(happens instantaneous for the purposes we are talking about, the 
coil is harmless (unlike a capacitor).

Another thumb rule for sparking and arcing. 10,000 volts will jump 
about 1 inch at normal atmospheric pressure. The one inch rule has 
many variables and inside the combustion chamber of an engine has 
very little to do with what happens outside at atmospheric pressure 
but I thought it was an interesting bit of trivia.

One other thing and I'm not picking on you if it is a typo. When
you 
refer to HT are you referring to HV for high voltage?
If not pleas let me know what HT is. 

Regards,

Mike D.


> Plug gap has absolutely no bearing on coil output. Is going to build
> up HT even if never grounded (that's why you have to be careful
> grabbing distributor lead wire even after ignition turned off -- if
> last plug never fired YOU'LL become the ground). Gap has everything 
to
> do with flame propogation, and ability of HT to jump (too big gap 
with
> too low voltage won't fire).
> 
> Bill Robertson
> #5939
> 
> >--- In dmcnews@xxxxxxxxxxxxxxx, "Elvis Nocita" <elvisnocita@xxxx> 
wrote:
> > 
> > I still don't get you guys with that high voltage stuff.
> > Tha max-voltage on the plugs depends of the gap (and the mixture).
> 
> > My 2 cents, and my book about car electrics and stuff proves me
> right....
> > 
> > Elvis & 6548