Date: Sat, 3 Oct 2009 10:10:08 -0700
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: Technique For Removing Speedo needle?
In-Reply-To: <20091003163924.8ABDB1165C3@hamburg.alientech.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
"Slope" is a good way to view it. My speedo reads 12% high. This has been
determined by GPS.* If I just had an offset then I might be tempted to
adjust where the needle points, though I'd hope that those with of a wiser
nature would try to talk me out of it, being the fumble-fingered fellow
that I am. But slope -- that's a horse of another color altogether.**
There doesn't seem to be a easy, cost-effective way to deal with that. So
I do the math in my head and subtract 12% (well, 10% is easier and close
enough) from what the needle says.
Maybe it would just be easier to re-do the artwork on the speedo face.
=============
* I'm running stock-sized tires.
** We've got a musical event coming up here. It's a Bluegrass version of
Dark Side of The Moon with various local artists. I'm definitely gonna go.
The connection to "horse of a different color" may be obvious to some.
--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
Bend, OR
KG6RCR
On 10/3/2009 9:38 AM Mike S wrote:
> At 11:43 AM 10/3/2009, Max Wellhouse wrote...
>> Has anyone tested the accuracy by spinning the speedo on the
>> work bench with a drill at say 60 rpm and have a value for that in
>> MPH?
>
> The speedo RPM for 60MPH is shown at the bottom of the gauge, something
> like 805 (it's revolutions per mile, same as 60 MPH).
>
> The problem is how do you know your drill is going 805 RPM?
>
> I've "calibrated" by using a GPS to determine my actual speed. I drove
> so the GPS indicated 60 MPH, and noted what the speedo read.
>
> Back home, take it out of the cluster again, and remove the back for
> older speedos, remove the impulse sender for newer ones. If you look at
> the mechanism, there's an outer fixed metallic shell, then a ring which
> moves with the needle, then a center portion which moves with the
> cable.
>
> Gently move the needle to the position you noted above. Take a
> permanent marker and mark the position on the ring and outer shell. I
> then wedged a toothpick in between the ring and shell to hold it in
> position. Remove the needle, double check that the marks are lined up,
> then put the needle back on, pointing to 61 MPH (so it indicates just
> over the actual speed). Check the marks again, and push the needle on
> firmly if they're still OK.
>
> Reassemble, and you should be done.
>
> This makes it accurate at the calibrated speed. That doesn't mean it
> will be accurate at any other speed. There's both an offset and a
> slope. The above calibrates the offset. Slope is calibrated by tweaking
> a spring, and/or the magnets in the mechanism, either should be left to
> a competent speedometer shop.
>
| 
