Date:         Mon, 14 Oct 2002 11:12:18 +0100
Reply-To:     Clive Smith <clive.harman-smith@NTLWORLD.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Clive Smith <clive.harman-smith@NTLWORLD.COM>
Subject:      Re: High Octane was: what's the best kind of gasoline?
Content-Type: text/plain; charset="iso-8859-1"

> >Pinking now and again is a different set of cylinder conditions and
doesn't
> >in the short term cause a lot of damage.
>
>   I believe it can crack heads and piston crowns...

 Yup, and maybe its part of the WBX problem too - maybe, I haven't lived and
breathed with one for years to find out - yet.

Pinking (tinkling) around town can go on for years, doing slight damage,
upsetting the top rings (shock waves) etc and is never 'good' unless you
want some carbon removed for free at a risk. On the Costas and in Portugal
in summer, you hear all the hire cars being laboured about around quaint old
towns in 2nd gear, pinking at every application of throttle (heat and fuel).
Presumably they don't all end up with cracked heads. A 'granny engine' can
do this light tinkling until its been taken on along run for a while or
Stans been at it with his Marvel Mystery Oil

Depending on the engine and as I said, we are talking about one helluva
subject, one helluva lot of engines, and one helluva grey area - I'm sure
quite a few engines can come to harm and suffer piston damage - there just
is no dividing line - but I'd say that IF it occurs at higher load and
throttle settings, rather than really light throttle, low rpm, then its an
immediate danger and should be sorted, at least with some higher Octane
fuel - the first job being to glance at the coolant temperature, and also
suspect a whiff too much advance.

Clive


----- Original Message -----
From: "Andrew Grebneff" <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, October 14, 2002 6:48 AM
Subject: Re: High Octane was: what's the best kind of gasoline?


> >High speed detonation isn't pinking. You'll not hear it at full power on
> >many engines,  but it'll damage the engine in seconds flat, the spark
plug's
> >earth electrode often being the first to go (with inevitable damage to
> >cylinder walls/rings) , then bits off the top ring land. Looking for
> >microscopic ally
>
> "Ally"... UK short for aluminum, the misspelled metal... in the UK,
> NZ, Australia etc... it was named, according to the rules for naming
> metals, after its ore alumina (NOT aluminia; the metal ending is -um,
> NOT -ium), by an Englishman. Pity the English journal introduced a
> typo... the US journal didn't.
>
> Had this problem on my old Honda CB450. Just ate the plug, right up
> into the threads... no engine damage, fortunately.
>
> >spatter on the plug's ceramic insulator will reveal
> >'incipient' high-speed detonation - always cast a cursory eye over your
> >plugs whenever they are out.
> >
> >Pinking now and again is a different set of cylinder conditions and
doesn't
> >in the short term cause a lot of damage.
>
>   I believe it can crack heads and piston crowns...