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Old 11-01-2018, 10:16 PM
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Default Tachometer brightness

Hi guys- not sure what I have here from the PO. Notice how the in dash tach does not have any of the luminescence of the 3 other gauge pods in the dark photo. U can also see where some type of paper backing in the tach at the top is eschew and some direct bulb light is peeking through. I am assuming this is a repo tach and just does not light up like original? Or is there some trick to get this to look like the others? Thoughts appreciated.

Included a shot of tach with flash too so u can see in light...
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Old 11-01-2018, 10:52 PM
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Not familiar with that particular year but I expect that maybe the bulb for that pod popped out of the hole and maybe that's why the light is bleeding through from the back but not actually illuminating the gauge face?

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Old 11-01-2018, 11:51 PM
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That looks like a plastic reproduction tach from about 15 or 20 years ago.


If it is, indeed is one of those, whoever made that had absolutely no clue as to how the dash gauges are suppose to light up at night.

Here are a few photos of that plastic tach opened up ( side by side next to a GM original 64 GTO in-dash tach) so you can see what's wrong with it.

You would need to take yours out of the dash and open it up to try and see what you might do to improve the night time lighting. There are 2 bulb sockets that go to that tach, they both plug-in from the backside.

The interior of any '64 GTO tachometer housing including the backside of the circle dial ought to be painted in several shades of light blue (so as to reflect the light coming from those 2 bulbs). To make the one you have better for night time driving you would need to study an all original '64 GTO tach opened up so you can see how GM did it. To start with I will post a few photos of the one I think you have. The housing to that is most likely made from black plastic which is a problem as the black can't reflect any light off of the bulbs.
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  #4  
Old 11-02-2018, 12:02 AM
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Quote:
Originally Posted by Greg Reid View Post
Not familiar with that particular year but I expect that maybe the bulb for that pod popped out of the hole and maybe that's why the light is bleeding through from the back but not actually illuminating the gauge face?
This is it - you’ll need to pull the instrument panel to take a look. It’s easier if you pull your front seats and your steering wheel out.

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Old 11-02-2018, 08:10 AM
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Ok thanks guys appreciate the feedback. Startling difference between real and repo. Great context. Taking out the instrument cluster would be way new for me. How big of a deal is that to do?

I will crawl under and see if I get lucky and it’s just a bulb loose. Still sounds like it’s a junk part so probably does not matter. But I’ll try and report back

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Old 11-02-2018, 09:42 AM
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Peter would it be crazy if I tried to paint inside of tach blue?

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Old 11-02-2018, 12:17 PM
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Default Tachometer interior light, the blue paint.

You could try that, the way the plastic tach is put together the circle dial does not appear to be a separate disc as in the way the GM parts were made. So you will never be able to have it light up at night and get a round illumination "halo" as with the other circles in your dash.


If you want to try painting your tach now; prime the black interior using a flat white primer first. Allow to dry for about a week. Then go with your light blue. Let me post up a few more photos of the interior pieces from the GM tach and you can see how the shades of blue were painted.

GM used reflected light to bounce the glow off of the bulbs and then off of the inside of the parts (painted in shades of light and medium blue) of that tach. It is the way all 1950s, 1960,s 1970s and 1980s GM car gauges were done so that they were visible at night.

First 2 photos are a tach housing that I restored. The 2 photos are before I put the parts back inside of it. I made a cardboard & masking tape template as far as the color and the separation lines went. The darker places are where they are toning down the glare off of the bulbs and the lighter blue is where they are putting more light potential down into your "view" area window.

Your best bet would be to look into a newer reproduction tach or a GM original. Those older plastic reproduction gauges are very poorly made and really, today, you have better choices.
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Last edited by Peter Serio; 11-02-2018 at 12:19 PM. Reason: added some more info.
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  #8  
Old 11-03-2018, 09:16 PM
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Ok I can confirm that repo example you have Peter is exactly what I have. Saw the back of my tach and it’s the same. So unfortunately it’s not loose bulbs. It is a garbage part. So two questions- peter do you have any of these tachs in stock? If not, a recommendation on where I should look?

is there anywhere that describes the steps to extract the tach from instrument panel in a 1964 lemans/gto? my shop manual does has a very abbreviated description to the degree that it’s not really useful. It is an ac car...

Thanks for thoughts

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Old 01-29-2023, 09:34 AM
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Coming back to this really old one as something to tackle this winter. Does anyone have a recommendation for one of these newer repo tachs that are good?

Also, I am not critical of year-correct stuff on my car and actually like the later year in dash tachs better. Can see the sweep better. what years are interchangeable with a 1964 cluster pod?

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