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Number: 4615
From: "Sandy Block"
Date: Mon Mar 1, 2004  4:55 pm
Subject: Re: [ASC McLaren ] NOW - - I NEED HELP !!!

Body:
Re: [ASC McLaren ] NOW - - I NEED HELP !!!

Thanks, guys. Regarding the Speedo, NO, it does NOT jump around
erritacly or boucne around. It reacts to speed changes very smoothly.

"S"

-- In ascmclaren@yahoogroups.com, "SNP Marq" <infosyssec@i...> wrote:
> Hi Sandy....
>
> My first thoughts on your tale of the mysterious 'whirrrr' sound
are this : That model of car would have a mechanical speedometer -
meaning that there is a flexible cable running from the transmission
up to the back of the speedometer. Basically the speedo cable
looks like a bicycle cable with a plastic coated wire outer casing
and a 'multi-wire' center core. The problem with the multi-wire
center core is that it has the potential to 'rust'.
>
> So if you can imagine this multi-wire core spiining around within
the plastic coated and metal reinforced jacket, there is the
potential for a bit of noise when a car has been sitting for quite
some time.
>
> Normally the inner tube of the cable is saturated in lithium grease
and the constant spinning of the inner wire keeps the lubricant well
distributed - hence little or no noise.
>
> If the cable is making the noise, it would travel the length of the
speedometer cable and you would hear it at the the speedometer and
down at the ratio gear at the transmission.
>
> Being a 'cheap SOB' I would do one thing to test the theory out.
Normally you can gain access under the dash to be able to get a hand
up an on to the back to the dashboard. I know for certain this is
possible with the Firebirds, and I seem to recall having done this
with my Mustang as well. Normally the part of the speedo cable that
clips into the speedometer is held in position by a clip that pinches
it from both sides. If you depress the clip you 'should' be able to
disconnect the speedo cable from the speedometer.
>
> Ok... having accomplished that.... you should 'normally' be able to
pull the inner core wire out of the cable that it is encased in.
Once out you can inspect it to see if it has the brown evidence of
rust. If everything looks shiny and black ( from the lithium
grease) than it may be that this was not where the problem was. You
can than recoat the inner cable with fresh grease and stuff it back
into the speedocable. The trick here is to make sure that when you
insert it that it goes all the way back down to the ratio fear and
fits back into it snuggly. The ratio gear end of the cable has been
formed to have a 'square' shape and by gently twisting the cable as
you reach the gear ratio you can ensure that you have insert the
square end snuggly into the square receptable at the rear ratio.
You than simply snap the speedometer end of the speedo cable back
into the back of the speedometer.
>
> NOW... if the cable turns out to have been rusty... than you can
steel wool the length of the cable to clearn all the rust shards off
the inner cable, re-grease it up, shoot some lithium grease down the
cable to grease it up, and than go through the re-insertion steps I
mentioned above.
>
> One thing about speedometers themselves, is that they are know to
go flakey at some point with normal wear and tear. In the case of a
vehicle that does not have much mileage on it, one would have to
assume that 'atrophy' may simply set in at some point - and affect
the speedometer mechanicanism in a way somewhat similar to normal
wear and tear.
>
> With regards to the possibility of just ignoring the sound and it
may disappear... I believe that is the course of action that most
people would take. If it was a lack of lubricant on the inner
speedo cable... than putting some milelage and use through the cable
would hopefully re-distribute the grease that is probably sitting in
the cable - bringing about silence.
>
> Similarly, if the speedometer itself has gone slightly wonka from
lack of use, than possibly putting some miles on it would also have a
similar positive effective on ending the 'whirring' sound.
>
> If the 'speedometer's time has simply come to act 'wonka' than
there is not much that can be done about that. Usually the initial
signs of the speedometer going 'wonka' is that the needle of the
speedometer jumps a bit eratically when driving along at a steady
speed. Normally you don't get to the noisy 'speedometer' stage until
the car has done a bit of erratic behavior in its reporting of your
rate of speed.
>
> Nuff said.. .hope this helps give you some additional thoughts.
>
> Marq