1967 sprite earth?

[longbridgehealey]

Brain dead moment - is a 67 negative or positive earth?

Thanks!
Larry

 

[dklawson]

If your question is aimed at originality I cannot help you. If your question is aimed at making sure you put a new battery in the car in the correct orientation, there is hope.

Carefully measure the two battery cable clamps on the car. The cable terminal with the larger diameter hole is the positive cable.

If the car has an alternator, that's almost 100% indicative that the car has been set up for negative ground.

If the car has been sitting for years and still has a generator, you probably should "flash" (re-polarize) the generator anyway just to make sure the generator has a working magnetic field.

 

[longbridgehealey]

Well, here’s what it is all about. I have a 59 Bugeye that, a few years ago, I replaced the 948 with a 1275 from a 67 Sprite. At about the same time, I switched the Bugeye to negative, and converted to a alternator. So now I’ve acquired a tach from a 67, and I want to put its mechanism behind the faceplate of my 59 Bugeye, but I don’t know its polarity.

 

[nomad]

Pretty sure they were still positive ground for at least a couple more years. Usually polarity is marked on the face of the tach.

Kurt

 

[dklawson]

As above, look carefully at the face of the donor gauge. It should say whether it is positive or negative earth.

EDIT: Sorry, it occurs to me that you are facing a couple of other issues.
1) Your Bugeye should have had a mechanical tach from the factory and you are proposing to mount an electronic tach behind its face. That may involve a bit more work than you expect.
2) The '67 donor tach is probably an RVI type. Keep in mind that the RVI tachs are generally not compatible with electronic ignitions. This is not a problem if you are running points but it is something to keep in mind should you wish to use an electronic ignition later.

Something that will increase your flexibility is to buy the Spiyda Design RVI tach conversion board (see link below). That board will convert the RVI tach so it functions like a later RVC type. At the same time it will give you more flexibility in calibration so you can better match the needle position with the Bugeye face.

Spiyda Design Tach Electronics Link:
https://www.spiyda.com/tachometer-electronics.html

 

[Jim_Gruber]

ened changeover from Negative to Positive Ground happened in 1968. My ‘68 Sprite was Negative Ground. It is possible to change a Positive Ground Tach to Negative Ground. Involves swapping a couple of wires. I’ve get a Step by Step from “The Godfather” Frank Clarici also an article in inserting electronic tach guts into a BE Tach.PM me if you need me to dig it out.

 

[nomad]

Doug's right on the RVI. If you are going to change the guts, a later RVC tach would be a better choice or a more modern junk yard tach out of a Japanese vehicle with the same sweep to the needle. As Jim mentions Frank described how.

I have a Spyida unit that I have been going to fit to a RVI. Haven't done it yet because I need some help from someone that is actually technologically up to date. Need a constant signal generator to calibrate it.

Kurt

 

[dklawson]

Need a constant signal generator to calibrate it.

Take a look at the Spiyda page linked below. It explains how to use a downloadable WAV file and your laptop PC (or cell phone) as a calibration source.

EDIT: It would help to provide the link!
https://www.spiyda.com/tacho-calibration-information

 

[nomad]

Thanks Doug....don't have laptop and I'm still using a flip phone!:rolleye: Need to talk my son into it.

Kurt

 

[dklawson]

I don't even have a cell phone but I do have a laptop. So... without a laptop and having a flip phone... how do you post here?

 

[longbridgehealey]

Thanks everybody, I think it’s coming together. And Jim, I have both those instructions from Frank, but thanks. Also, check your messages, I tried to answer the one you sent me. I’m not very good with this messaging thing!

 

[nomad]

I don't even have a cell phone but I do have a laptop. So... without a laptop and having a flip phone... how do you post here?

Doug, they still have these things that sit on a desk! Not very portable though.

 

[dklawson]

Doug, they still have these things that sit on a desk!

Cats?

I agree, desktops aren't very portable.