The Stovebolt Site Forums The Shop Area Interiors AD Speedometer Freshening

Video 2:

https://share.icloud.com/photos/0ab7ceXuASwNtT1ps3XQC9BoA

I didn’t hit record on time, but the needle very slowly rose to its position when the video started, and then you can see it climb a bit more. Seemed to be sort of leveling out at 12 mph.

Weak magnet or friction/ resistance somewhere in the system?

That needle looks very sluggish like it’s rubbing maybe
How does it behave if you move it with your finger
Lift it up and let it drop
-s

Watch video 1 for that

If I hold the speedometer head parallel to the ground, I can blow with my mouth and push the needle up to 40-50 mph with minimal effort.

If I push the needle with my finger, there is very little resistance until you get somewhere north of 60mph. Above that, you can feel the spring resist more.

Not sure what “normal” is supposed to feel like, but I’m leaning toward the magnet vs some kind of friction issue.

I don’t know how the spring would be any stronger that it was before. The needle spindle…should it be lightly lubricated where it passes through the bracket that holds down the cup? Or perhaps where it passes through the gauge face? I did not do that.

Okay that sounds normal then
Seems maybe the poles aren’t saturated sufficiently
-s

I’ll get some new magnets coming.

Should have some bigger, better magnets here tomorrow. A couple questions in the meantime:

1) Would it be a good idea to lightly polish the inside of the copper cup? Say with some fine scotch brite? Mine is kinda grimey.

2) Any suggestions for creating more of a snug fit for the needle hub on the spindle? I think mine will creep a bit as it over time as it contacts the stop. Thought about a tiny drop of blue loctite. But I don’t want to do anything that will make future removal impossible.

There is little value to polishing the inside of the needle cup and you might damage the clock spring in the process
If that tiny spring is disturbed and bend from its factory shape the speedo will read wrong

The needle could be made to fit tighter by ever so slightly putting a dimple onto the tiny sleeve that is embedded in the needle counter balance weight
I’ve had that sleeve pull out the weight on some units and I had to glue it back in
But be carful it’s such a delicate area
I haven’t ever had to make a needle fit tighter, it’s usually the opposite situation for me but I’ve only worked on few to date.
-s

All back together after 24 hrs with some much larger and stronger magnets. Medium drill speed (which I think is 1100ish) still registers about 40 mph.

I think I’m about over it. It might just need to go back in the dash. At least it’s steady and quiet now.

Somewhere I believe I have a head I rebuilt to use as an example of how to do it (not here...for another forum). Do you want me to see if I can find it?

Could the clock spring be a whole turn too tight?
Did you take it out or move it too much maybe?
I’m curious what is going on here
-s

I spent a fair bit of time studying and fussing with the spring based on that same theory. Best I can tell, the spring is set at its natural resting point. Another turn “loose” is sort of forcing it loose and it gets all weird looking.

However, I’ve learned that sometimes things look differently of you step away for a day. I will probably try once more to see if another turn in the loose direction is a possibility.

Also need to make another run at validating my strobe tachometer. Perhaps I’m worried about nothing here. I borrowed one from my parents but it was some sort of modern USB thing that was much smaller. I’ll just make a mark on the balancer if one of our vehicles and check it.

Sending you an email, Jon G.

May have had a little breakthrough. Wanted to test my free strobe tachometer app against another tach. Made a mark with whiteout on the crank pulley of my sons Nissan and started it to let the idle steady out. The dash in the truck says 750ish rpm, and the tach thinks it’s 1200ish.

The strobe tach thinks my drill is spinning at 1075 rpm and that speed spins the speedometer up to 38 mph. But that 1075 (via the wonders of cross multiplication) is something more like 671 rpm. 671 rpm should be 40 mph.

It’s dang close if all these assumptions are correct.

I’d still like to validate the drill speed via something more accurate. Once I button up the dash…I don’t want to do it again for a very long time.

I checked another free tachometer app against my 1951 where I can dial the idle speed with just one screw. Running my drill on high, once adjusted for error, is something like 925 rpm. That drill speed produces 54 mph on the speedometer.

I’m gonna call that close enough. Thanks for the help, yall.

Let us know how it compared to a gps speed app on phone when you are driving at a steady speed down the highway later
Hoping for the best of luck for ya!
-s

I’ve not had any time to button the dash back up. I’m going to attempt some “pre-work” for my rewire project to minimize the pain and suffering later.

Another thing I’ve been noodling on:

Some different hardware to make gauge/ speaker grill removal easier. I bought a few knurled brass thumb screws for areas where socket access to the backside gauge mount it nuts is tough. Going to experiment with that.

I’d really like to find some longer nuts, like coupling nuts. Might have to order online. The only #10 coupling nuts I’ve seen locally are coarse thread.

Curious if anyone else has a suggestion for making dash disassembly less awful.