Pinging can be caused by dirty disposits of cabon on the pistion crown, and other selected areas of the combustions chamber. Street engines are bad about acummulateing such deposits. This is why is isimportant to tear down highmilageengines, just to cleanthem if for no other reason. Hope tis helps, Dave A12
Thor Lancelot Simon wrote:On Tue, May 06, 2003 at 03:15:24PM -0700, Chris Krok wrote:
>
> > From: Zachariah Mully
> > Subject: Re: Re: Carb question
> >
> > How would a lean condition cause
> > pinging? Simply by raising the cylinder temperature to a point where it
> > pre-ignites the fuel?
>
> I think that's basically it... Don't have firsthand experience, but I
> do know that guys who mod turbo cars have to increase the fuel supply
> (lower the A/F ratio) at high levels of boost to suppress detonation.
Another option is to run a cooler plug, but that hurts combustion
efficiency more. I think the actual problem is often that the spark
plug can stay hot enough, in a really lean condition, to occasionally
act like a glow plug...
In the turbo-Volvo circles I used to hang out in (I kid you not, there
is a whole culture of folks who hot-rod their Volvos!) two semi-popular
hacks for addressing this were:
1) Run bigger injectors than stock, so more fuel per pulse than the
engine computer thought, thus more heat in the cylinder at the end
of the combustion cycle but less risk of detonation (this probably
would work a lot less well in an engine without an intercooler).
2) Rig a 2- or 3-liter soda bottle to drip *water* into the intake
(at any of several convenient points) at a very slow rate. This
does not actually hurt combustion in any significant way but
cools the cylinder, plug, and all a *lot*, thus allowing more
turbo boost, a hotter plug, a leaner mixture, advanced timing,
or whatever other detonation-prone modification might be desired.
On the other hand, you'd have to stop every so often to refill your
water bottle.

I think this was much more popular at some point
in the past when SCCA rules had a loophole permitting "water injection".
Thor
List sponsored by Dual Sport News at
www.dualsportnews.com. List FAQ courtesy of Chris Krok at:
www.bigcee.com/klr650faq.html
Unsubscribe by sending a blank message to:
DSN_klr650-unsubscribe@yahoogroups.com .
Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
---------------------------------
Do you Yahoo!?
The New Yahoo! Search - Faster. Easier. Bingo.
[Non-text portions of this message have been removed]