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Re: Speedo changing speeds?

To: Atwell Haines <carbuff@tempest.nac.net>
Subject: Re: Speedo changing speeds?
From: "Kirby T. Kenyon" <kenyonkt@maple.lemoyne.edu>
Date: Fri, 11 Sep 1998 08:44:27 -0400
You mean my raisin is dried up?  If I put a plum in there, will I go
slower or faster?

Atwell Haines wrote:
> 
> At 08:48 AM 9/10/98 -0400, Kirby T. Kenyon wrote:
> >I've got a weird one on my '80 Spit.
> >
> >I drive the NYS Thruway to work.  When I drive my Spit, early in the
> >drive the Speedometer reads the correct speed (70MPH @ 3400 RPM with OD,
> >verified by time over mile marker method) but approximately 30 miles
> >later, it reads low (63MPH @ 3400 RPM).
> >
> >I verified that I was still going about the same speed at the end of the
> >trip that I was in the beginning so I know there is no slip in the drive
> >train.
> >
> >Could this be a symptom of a slightly binding speedo cable?  It does
> >bounce some at lower speeds but smooths out about 30MPH.
> >
> >Has anyone else encountered this?
> 
> Kirby,
> 
> To answer this one it is neccessary to understand the principals of
> speedometer operation.
> 
> Inside the Instrument is a small yet nimble mammal (similar to a Marmot,
> but not really, and on a much smaller scale.)   The one in my car is named
> Eric.
> 
> As the car goes faster or slower, a raisin is held closer or farther from
> Eric's nose, causing him to run correspondingly fast or slow.  This moves
> the needle you see from the cockpit.
> 
> After several miles, Eric is tired from all that running (and on a toll
> road no less!) so it is understandable that he runs a bit slower when the
> car is going the same speed.
> 
> This is not always a real problem.   Do not be concerned, unless Eric
> starts leaping and jumping, in which case he is on his "Last Legs".  In
> that case you may have to rely on the Tach to gauge your speed.
> 
> Sometimes the raisin falls out of the speedometer.  In this case, the
> indicated speed will be zero.
> 
> Please try to be more understanding of the forces at work inside the
> machines we use every day.  I hope this helps you.
> 
> Your Public Servant,
> 
> Atwell Haines
> '79 Spitfire  FM96062 UO
> (53 HP)
> 
> Succasunna, NJ USA
> 
> The One Immutable Rule of Automotive Satisfaction:
> "It is more fun to drive a slow car fast than to drive a fast car slow"
> - Cory Farley in Autoweek, 8/17/98

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