[Date Prev][Date Next][Thread Prev][Thread Next]
Re: [ST] General thoughts on ping
- Subject: Re: [ST] General thoughts on ping
- From: John Ulizzi <jaulizzi@xxxxxxxxxxxxx>
- Date: Thu, 1 Jun 2006 04:00:43 -0700 (PDT)
Carbon build up? In one of your motors ? Yea ,
--- Jonathan West <triumphnutter@xxxxxxxxx> wrote:
> So, I don't know who originally posted the original
> "ping" thread but here's my
> thoughts on it. Sorry it's late, I'm just getting
> caught up from the holiday
> Ping=pinking=kock and ping=detonation. It's all the
> same thing. It can be
> catastrophic to an engine if ignored. It can warp
> pistons, damage valves,
> destroy rings... any number of really bad things.
> It literally hammers the
> combustion chamber when it happens. It is nothing
> more than part of the
> fuel/air mixture exploding prematurely due to a
> number of different causes.
> Essentially, the fuel air mixture is ignited by the
> spark, and the resultant
> flame travel and gas expansion compresses the rest
> of the mixture to the point
> that it detonates prematurely before the flame
> travel can consume it. It's
> like two different explosions, and the combination
> of the two is way more than
> the parts were ever meant to handle. The poor
> timing of the second explosion
> is counterproductive to the mechanical efficiency of
> the power stroke. It can
> be catastrophic.
> How do you eliminate it? There are a number of
> factors that affect it.
> 1) Detonation thrives in high temperatures. Try to
> avoid heavy throttle in
> slow moving traffic where the engine temps might be
> higher. Also, full
> throttle at low rpm increases the combustion chamber
> pressures moreso than full
> throttle at high rpm, so know that you are inviting
> detonation by doing this in
> an engine that is susceptible to it.
> 2) High Octane fuel helps quell it due to the slower
> burn rate. The slower
> burn rate helps mimimize the compression of the
> unburnt fuel so it does not
> ignite prematurely. That's why the best octane fuel
> is the lowest octane you
> can run without detonation.
> 3) Retard the ignition timing. Starts the whole
> ignition process later in the
> stroke giving it less chance of detonating due to
> lower compression speed.
> Obviously you're not gonna change this without a
> 4)Reduce compression ratio. Clean out any carbon
> buildup on the piston or
> chamber that is consequently shrinking your
> combusion chamber volume, and
> thusly raising your compression ratio.
> 5)Sometimes a colder range spark plug can help...
> all this does is dissipate
> more heat into the head, so depending on the design
> of the combustion chamber
> and how the flame propagation and travel was
> originally designed and
> anticipated, this may or may not help. In other
> words, you could be putting
> more heat into the wrong place with a colder plug.
> Incidentally, my 99 ST started doing this same thing
> on 89 ocatane fuel. I've
> been using 91 or better and have not had any issues.
> I have to wonder if there
> is substantial carbon build up now with 24k miles.
> It did not always do it. I
> would also be inclined to believe that the fuel
> quality is not what it was
> years ago.
> Anyway, hope this helps whoever was having trouble.
> Good luck,
> Jonathan West
> Do You Yahoo!?
> Tired of spam? Yahoo! Mail has the best spam
> protection around
> Triumph Sprint ST/RS mailing list
> Send list posts to ST@xxxxxxxxxxxxxx
> Change your list options at www.Triumphnet.com
Triumph Sprint ST/RS mailing list
Send list posts to ST@xxxxxxxxxxxxxx
Change your list options at www.Triumphnet.com