Re: [ihc] RE: David's decarbonisation

[Steven Stegmann <steve.stegmann@xxxxxxxxxxxxx>]

The combustion chamber deposits can cause hot spots
that are actually glowing.  When a fresh charge comes
into the cylinder, this ignites it ahead of time,
usually shows up as pinging.

With a carbureted engine this causes dieseling when
you switch off the ignition.  There's still a source
of ignition you can't shut off but it isn't occuring
at the right time so you get dieseling.  Sometimes the
engine is running backward, seen them do that.  Really
rough and ugly running.

Steve
--- "ken.dunnington" <ken.dunnington@domain.elided> wrote:

> Jim Grammer wrote:
> 
> JG> Back in the day, a tune up at a good shop
> included pouring a can of
> JG> 'combustion chamber cleaner' down the carb as
> quickly as possible without
> JG> killing the engine. Said cleaner was a witches
> brew of aromatic solvents,
> JG> and produced great gouts of satisfying white
> smoke out the tailpipe. Very
> JG> impressive :)
> 
> JG> I use mineral spirits in place of ATF or
> SeaFoam. Fill a mustard bottle(with
> JG> the dispenser nozzle) and trickle it in as
> rapidly as you can.
> 
> 
> OK, so I'm a little slow on the take here...
> 
> The carbon could be the source of the "diesel"
> rattle David reports.
> Is the rattling noise the reason for the combustion
> chamber cleaning
> or was it something else?
> 
> In my "piston slap" post I mentioned a manufacturer
> that had some
> engines produced with piston slap resulting in a
> knocking sound.
> In my readings concerning folks' experiences with a
> rattling noise
> inherent to their relatively new engine(less than
> 10K miles) I did
> read of owners of the same model engine, without
> piston slap, but with
> 50K-75K miles on the odometer, experiencing similar
> noises.  More than
> once I read of excessive combustion chamber deposits
> being blamed as
> the cause of the noise.  IE, cleaning of the
> combustion chamber
> resolved the noise issue.  I do not recall whether
> the cleaning was
> achieved by pouring solvents into the intake of a
> running engine or by
> disassembly, but obviously, pouring some mineral
> spirits down the
> throat of the carb is a quite cheaper/easier
> possible solution.
> 
> Unfortunately for the low mile "rattlers" the fix is
> not nearly so
> easy on the wallet.
> 
> Are there possible detrimental outcomes to the
> solvent down the carb
> "trick"?
> 
> Ken