Date:         Sun, 13 Oct 2002 13:08:33 +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?
Comments: To: Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Content-Type: text/plain; charset="iso-8859-1"

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 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.

Clive

----- Original Message -----
From: "Andrew Grebneff" <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, October 05, 2002 8:31 AM
Subject: Re: High Octane was: what's the best kind of gasoline?


> >
> >The key is to listen for pinging. If you can't hear your motor very
> >well, try warming the motor up thoroughly, then take the motor cover
> >off, and drive up a fat hill in 4th. Ping? Retard the advance slightly.
> >No ping. No worries.
>
> Be careful. Just because you can't HEAR pinging, it doesn't mean that
> it itsn't happening (ie subaudibly).
> --
> Andrew Grebneff
> 165 Evans St, Dunedin 9001, New Zealand
> <andrew.grebneff@stonebow.otago.ac.nz>
> Seashell, Macintosh, VW/Toyota van nut