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How do you get into an early type speedo

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bob hughes

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Hi Guys

I am following Rogers trail to improve the lighting in the speedo and rev counter. I have a BJ7 so have the earlier mechanical drive type speedo. I am experiencing difficuly in removing the mechanical bits inside as I want to spray the inside of the can white. The bezel and the glass is off at the front and the two screws at the back have also been removed. The mechanism is free to move around inside the can but the trip meter reset spindle and / or the dial is in the way of removing the mechanism completely. There are two very small screws on the dial face that may hold the clue, if they are removed then the dial may tilt enough to clear the can and allow removal. Has any one carried out this operation?

By the way I will be posting some piccys and information on bulbs and holders for the instrument lights on Rogers thread later today.

:cheers:

Bob
 
Done this many times with my BJ8 speedometer (all Healey speedometers are mechanical). The face must come off. GENTLY pull the indicator needle straight out and unscrew the two screws (jeweler's toolkit works best). Then, the odometer reset shaft comes apart--should be a tiny roll pin unless it's been replaced with a cotter/split pin--and is spring-loaded so it has to be pushed up through its hole. You can contort the mechanism and get it out now, but it's easier if you remove the housing for the high beam light--which will have to come out when painting anyway--gives a bit more wiggle room. It's got a weird--British (just teasing)--little spring clip retainer but it's evident how it should come out.

The indicator needle stop is spring-loaded; before you remove the needle depress it and let the needle come to rest with the unit held in 'normal' position. You'll want to replace the needle in the same location to retain your calibration. There's also a tiny white dot at what would be the -5 ('minus five') MPH location, and that's the normal calibration point.

This might help: Anthony Rhodes' Smiths/Jaeger speedo info doc
 
I wouldn't do it! Even the most careful will damage something.
You could locate a broken spare, (as someone else's mistaken efforts) and paint that one, then ship all to Nissongers to reassemble, calibrate etc.

Just my humble opinion.
 
Johnny said:
I wouldn't do it! Even the most careful will damage something. ...
Click to expand...

Please allow me to respectfully disagree. I was intimidated by instruments, too, but got tired of being without for two weeks to a month and spending $200 every time something went wrong. I did pay to have gears replaced when I went to a 3.54 rearend because I had no idea where to get the parts, but could now put the old gears back in if I go back to the 3.91.

Yes, the parts are small and disappear easily, but there is nothing magical--or even particularly fragile--inside a mechanical speedometer or tach (I haven't messed with the electronic tachs, except to calibrate). It's not a Rolex. Keep in mind a lot of people won't touch a starter, or generator, or voltage regulator or even an engine because, well, because they haven't tried it (or they have and failed, but that's different and not applicable to the people on this forum).

Work on a clean, flat surface (I lay paper towels down on my kitchen table). Get a jeweler's toolkit. Read the doc I linked to. Study the instrument carefully; taking notes and/or photos isn't a bad idea. Pay attention. Be patient. You CAN do it (esp. if it's just to paint the case). While you're in there and your confidence has built you might pull the magnet housing apart and clean and apply fresh grease to the 'drive shaft.' The original grease is likely gone, or dry and hardened and isn't helping even if it isn't causing any problems (yet).

If you truly are a total fumblefingers by all means pay someone else to do it. But, I find this work interesting and satisfying. Also, I have a spare for parts. Yep, that helps a lot.
 
Right on Bob!
I agree with you and how you expressed it.
Some of us will venture into the unknown, not sure of what we are getting into, but with the right frame of mind and laying things out like you explained, we learn along the way, then share a how-it's-done with our peers. Good for you for digging into this. You're going about it the right way. Best of luck!
Roger
 
:blush:

Thanks for the replies guys but I have done it, I was looking into removing the needle but in the end I discussed it wih my friendly Healey guy ( I only use him as a last resort otherwise I will wear out my welcome)and he said that I had to be strong and forcefull, in actual fact it comes out if you push the reset pin right in and push out the threaded end where the cable attaches - there is a slight scraping of threads and it is out.

I have now lined the can with self adhesive aluminium foil and polished it up further with some silver polish. When testing it as a mirror against the house lights it works a treat.

Looking at the ring enclosing the glass, it is painted on the back and I would think that is to reflect the light seeping around the edges of the dial back onto the dial face.

I am now sourcing the reset pin and all the bits that attach to it as the existing is broken. There is a firm in South Wales that make the parts for Smiths instuments so I am hoping that there will not be a problem.
I will keep you posted
:cheers:

Bob
 
"Ring enclosing glass" = bezel

Not really, the glass is located in a stepped ring, black or dark on the 'front' face/edge and an off white on the 'rear' facing the dial. The chrome bezel along with a rubber ring clamps the glass setup to the can.

Thanks for the lead to Nisonger by the way.

:cheers:

Bob
 
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