jaltman@altlaw.com wrote:
>
> Well, the advance has to exist (either in mechanical or vacuum or some
> combination of both as the early 6 has) because even as the engine goes
> faster the explosion from the gas still occurs at basically the same rate.
> Therefore the spark needs to occur earlier in the stroke at higher speeds
> for the main force of the explosion to occur at the "right" time.
>
> There is debate over the reason for the retard, some here on the list think
> it was for emissions, others think it gives a smoother idle. Me? I am exempt
> from emissions testing and have my retard disconnected and think I have a
> smoother idle without it. My timing is set 10 BTDC.
>
> Nonetheless there is never a time when both function. Look at the diagram
> of advance and retard in the catalogs for the 69 6 (BTW Moss and VB have the
> dizzy connections reversed, TRF has it right), but notice that there is a
> switch in the line operated by the accelerator shaft. The retard only
> functions at "foot off the gas" idle. Moreover, retard is connected to
> manifold vacuum, which declines as engine speed increases, as opposed to the
> advance line which connects to the carburetor and increases vacuum as speed
> increases.
>
> Jim Altman jaltman@altlaw.com Illigitimi non Carborundum
> http://www.altlaw.com/metro/jaltman.html 69-TR6#CC28754L W4UCK
>
> -----Original Message-----
> From: owner-triumphs@autox.team.net
> [mailto:owner-triumphs@autox.team.net]On Behalf Of Janssen, Lee K
> Sent: Thursday, October 08, 1998 8:11 AM
> To: 'triumphs'
> Subject: distributor advance/retard
>
> Could someone explain why the early model TR6s had both a vacuum advance AND
> retard??
> Thanks for the info.
> Lee Janssen
> Denver CO
On a Model "A" Ford the spark advance/retard is located on the steering
wheel, when starting cold you "RETARD" the spark completely, as it warms
up you slowly pull down on the control to advance it until when running
and warmed up completely the control is at full advance. Move the control
just a small amount when warm and the engine boggs down, starting when
warm always advance the spark completely. Also the gas mixture is also on
the dash for adjusting for richer or leaner as well as the choke. Ford's
were also post. ground until 1955 and this guy was a true pioneer. The
rear brakes on the datsun 240Z to 300ZX were the same as the "A" design,
one set of brake shoes, one set for the emergency brake, same today on
the Datsuns. Any way this guy was a real pioneer in automotive
engineering, and it seems still is today.
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