Date:         Mon, 14 Oct 2002 18:48:11 +1300
Reply-To:     Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Subject:      Re: High Octane was: what's the best kind of gasoline?
In-Reply-To:  <007a01c272b1$40cf4ae0$0d00a8c0@TIGER>
Content-type: text/plain; format=flowed; charset=us-ascii

>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...