12 replies to this topic

[new_van_man]

Hi,

I have fitted an electronic dizzy and followed the wiring diagram posted on here. Now i also have a 3 clock dash. I have found the two wire behind the dash and connected them up but my query lies with the wires at the coil end.

The coil currently has teh following wires into it

Black and white wire from module on dizzy to neg terminal of coil. (replaces standard black and white wires on one plug for standard dizzy. i also have aonther white an dblack qwire i think which is on its own which is meant to go to the dizzzy.

So my query is this. In order to make the rev counter work can i connect the other black and white wire " on one clip tothe -ve on teh coil, will this interfere with the electronic module? Or do I need to separate tehtwo wires and only add the wire for the rev counter?

Any help much appreciated.

Cheers,

[dklawson]

I have no first hand knowledge about Lucas electronic ignitions. However, a voltage pulse sensing tach (like those that would have been used in the 3-clock dash) will have a sense wire that should be connected to the coil (-) terminal (the terminal with the wire going to the dizzy).

The sense wire is a high-impedance connection so it will not affect the operation of the ignition module. The voltage on that wire will swing from 0V (earthed when the module is conducting) to about 14V when the module is not conducting. Those voltage pulses/swings will be "counted" by the tachometer.

[Mini Ed]

Hi Everyone
My first post in the world of Mini’s; I not long ago bought a Morris Cooper 998, and decided to upgrade to an Electronic kit (Accuspark 25D) after a lot of messing about with the Points & condenser.

This was fitted, and tuned on a rolling road, it was then noticed that I had lost the Rev counter (separate Smiths Rev Counter) directly after fitting the Electronic kit.
The Black & white wire (negative earth) that was connected to the Dizzy terminal was left off, as there was not terminal point on the kit. I spoke with the manufactures, in which they said it should work, and that the wire should be connected to the negative side of the coil, in which we did and still no joy it.

Will the pulse be good enough to detect on the Rev counter? Or will I need to fit another mod?

I still need to trace the cables, to make sure another fault hasn’t developed, but I can’t believe this would be a coincident?

Cheers

[dklawson]

Electronic kit (Accuspark 25D) after a lot of messing about with the Points & condenser.

noticed that I had lost the Rev counter (separate Smiths Rev Counter) directly after fitting the Electronic kit.
The Black & white wire (negative earth) that was connected to the Dizzy terminal was left off, as there was not terminal point on the kit.

Will the pulse be good enough to detect on the Rev counter? Or will I need to fit another mod?

There are several possibilities.
You said the engine had points before. Did you install the electronic ignition or did you have this installed by someone else? On cars with points AND a tach, the normal wiring scheme is for a SHORT white/black wire to connect coil (-) to the distributor. A SECOND white/black wire (also connected to coil (-) ) passes through the firewall and is connected to the tachometer sense terminal. You MAY have connected the wrong white/black wire. If you connected the short white/black, the other end of that wire is not connected to anything once you fit the electronic ignition.

Since you say this tachometer is a separate add-on, are you sure that prior to installing the new ignition that the white/black wire ran to the tachometer? Being an aftermarket part, perhaps a previous owner installed the gauge using a different wire color.

More serious would be if you have a Smiths RVI tachometer (look for those letters on the gauge face). An RVI tach does not connect with a single wire but is connected in series with current flowing to/through the coil. RVI tachs also tend to NOT work with electronic ignitions.

Take a look again at the wiring and tach face and let us know what you find.

[Mini Ed]

Thanks for your help Tech Doc.

I got Sanspeed at Bexleyheath to fit the Electronic Kit. When fitting the kit, the negative cable from the electronic kit was too short in reaching the negative terminal on the coil, in which he extended. I must say I didn’t study the wiring as Pete was working on the car. It’s strange why you would only need to extend the negative cable, when the positive wire reaches the positive terminal on the coil okay.

Should the negative cable from the electronic kit be fitted to the white and black cable that was initially fitted to the Dizzy? I believe this is the problem??

I’m not sure if the Morris coopers were initially installed with Rev Counters? I’ll check the clock identification tomorrow, but I believe it’s not a RVI.

Many thanks for your help.

[dklawson]

The early cars with "Cooper" in their names would not have originally had a tachometer. Factory tachometers came about later when the gauge clusters positioned in front of the driver arrived.

The way most electronic ignition (add-on) modules work is by connecting two wires. On negative earth cars a (typically) red wire is connected to a switched 12V source. Sometimes this is the coil (+) terminal if the car does NOT have a ballast ignition system. The second ignition module wire is typically black and it connects directly to coil (-). The factory white/black wires are typically disconnected when the electronic ignition is installed. Like you, I am a bit surprised that the shop had to extend one of the wires.

Do take a look when possible to see what wire colors are connected to the coil and look to see if other wires in the vicinity of the coil and distributor have been left disconnected. If possible, also look at the wires connected to your tachometer. If you have a later RVC type tachometer (which only has one connection wire to the coil), look carefully to see what color wire is attached to the male bullet connector on the back of the gauge. You may find that same color wire has been left disconnected in the vicinity of the coil.

[Mini Ed]

Problem solved.

I disconnected the Black wire (which was extended) from the Dizzy to the (-) negative terminal on the coil, and re-connected the original white/black wire that was fitted to the Dizzy to the Electronic black wire (negative). Car started first time (which took around 10 attempts prior, when incorrectly wired) with tachometer now fully working!

The tachometer which is fitted to the car is indeed a RVI counter, so all appears to be okay, other than an increase in rev’s once the car is warmed up... another challenge for another thread.

Thanks for you help Doug, invaluable to us noobies

[dklawson]

I guess I remain confused about what the "black" wire is that allows the engine to operate when disconnected. I thought from your earlier post that the extended wire came from the ignition module... so if that were disconnected the engine should not run. Regardless, I'm glad the engine starts easier.

Returning to the RVI type tach, it is not a modern type. They date from the mid-1960s and were not used after the mid-1970s. Modern tachs sense voltage pulses using a single wire connected to the coil (-) terminal. The RVI tachs used an inductive loop in/on the tachometer to monitor current (not voltage) pulses to/through the coil. To achieve this the RVI tachs were wired in series with power flowing to the coil (two wires, not one).

As I mentioned earlier, RVI tachs typically do not work well with electronic ignitions. You observed that the RPM do not read correctly now. If your readings are even close you are among the very lucky few. I cannot recommend spending money having this tach recalibrated. It was designed for use with points and is likely over 40 years old. Most people replace them with RVC tachometers or have them converted to voltage sensing.

[Mini Ed]

The Black & white wire (negative earth) that was connected to the Dizzy terminal was left off, as there was not terminal point on the kit. I spoke with the manufactures, in which they said it should work, and that the wire should be connected to the negative side of the coil, in which we did and still no joy.

The electronic module black wire went directly to the (-) negative on the coil, so the car was running. The initial white/black wire to the dizzy was left off by the garage, which must of by passed the tachometer. Pete, tried connecting this white/black wire that was fitted to the dizzy to the negative terminal on the coil, which failed to work the tacho.

Interesting comments regarding the taco type; when the car is hot (normal temperature) the taco reads around 1800rpm, I tried bleeping the throttle & lifting the accelerator pedal, which can lower the Revs, a noticeable change is audible. Which was also the case with the point & condenser configuration.

The Crabs are Twin SU 1” ¼, with two K & N filters (doughnut type), I think it may have something to do with a return spring, but having said that the idle with the coke off when cold, is not as high - 1000rpm.
Back to the RVI counter, there are two whites at the back, and a number of other wires going into the back of the taco. I’ll look into getting this converted or the RVC type, once I can establish the cause of the idle increase.

Cheers

[Dan]

Can you get a photo of the back of it? I suspect it's already been converted if I'm honest.

[dklawson]

To be honest, replacement with an RVC type is much less effort and expense than paying for conversion.

If you see two (2) white wires on the back of the tach, it is still an original RVI. The two white wires are the ones wired in series with current through the coil. There should also be a green wire (switched 12V power), a black earth wire (may be on a spade lug or fitted with a ring terminal on a threaded post). Finally there may be an additional wire which may be one of several colors (white, red, white/red...). That last wire should be connected to the illumination lamp for the gauge.

[Mini Ed]

https://picasaweb.go...feat=directlink

Not sure if you can see the image. I believe the RVI tachometer hasn't been converted. Might be easier just to replace the Tacho with a RVC gauge.

Thanks.

Edited by Mini Ed, 21 September 2011 - 10:20 AM.

[dklawson]

The picture does indeed show the back of an RVI gauge. Note the loop of white wire secured to the back of the tachometer. That external loop indicates this is an "early" unit from the mid to late 1960s. The multiple connection points for the other wires indicate this is probably the type that can be run on 6V and 12V cars and that the gauge can be set up for both positive and negative earth.

Apart from their inability to work accurately with modern electronic ignitions, the type of RVI gauge you have is very versatile.