Rev counter wiring

[john_classic]

Hi all,
I've got hold of a 2nd electronic rev counter (blew the first one by wiring it incorrectly!) from a 2.5pi and I was hoping someone could check the wiring for me so I don't destroy this one too!
I'm fitting it to my GT6 so I don't have a handy haynes manual or any other reference and I've had no joy from google.
There are 4 connectors from top to bottom:

1) male bullet connector.
2) male spade connector.
3) female bullet connector?
4) male spade connector.

1) I'm guessing is a +ve or -ve coil connection not sure which.
2) Earth?
3) I'm guessing is a +ve or -ve coil connection not sure which.
4) Must be a ground as it's connected to the casing.

Any pointers welcome!

[john_classic]

I hate to bump my own thread, but, does anyone know how to wire one of these up?!

[Silvery]

Not a clue, sorry! Best bet would be to look at a 2500 dash harness if you can. This counter obviously has fittings that can only be wired up one way with the original wiring, so knowing what colour wires go where and tracing them back on a diagram would obviously be the best bet, but I guess you already know that!

Not sure why there's so many connectors though. Could it be the counter sits in the middle of the LT circuit, instead of taking a wire off the coil like normal? In which case I'd say male spade earth, male spade positive (that'll be insulated by a plastic grommet most likely), and then the two bullets for the LT circuit.

The only counters I can clearly remember fitting (I think I had one that sat in the LT circuit many years ago, but it's a very dim memory) have three connectors - Positive, negative, and wire from the coil. That's certainly how the ones in my Dolomites have been, and how the TIM pod one I've got kicking around wires up.

[john_classic]

Thanks Silvery,
I think it's an early rev counter... read in another thread that the early ones have 4 contacts and later ones only 3 (unfortunately the thread didn't metion how to wire one up!).
I'm afraid you're gonna have to tell me what LT stands for (not heard of that before)  :B

Hey TimB... did you have a diagram of the wiring?....

[Silvery]

Sorry, LT = Low Tension, as in the switched 12v to the coil, and the points to earth switched coil to dizzy.

I have some vague recollection of trying to fit a similar counter to some car or other in the past, it took the coil to dizzy wire in one connection, and back out another to the dizzy, ie it was "in" the circuit instead of being on a spur, if that makes sense? I also have an even vaguer recollection I fried it trying to fit it, so I'm probably not a lot of help!

[john_classic]

That sounds familiar, I fried the last one!

Anyone else have any idea?  :-/

[john_classic]

Just to let you all know, I got it working:

1) +ve 12Volts
2) +ve 12Volts
3) LT (+ve) side of coil
4) Earth

It's eratic as hell, swooping from 2000 to 3500 on tickover!
After some googling I have finally found some info on these puppies and there are two types:

This one was an RVI which usually doesn't work with electronic ignition and even if you do get it working, does not give a very useful reading ( I can vouch for that! :-/)
The other type (which I previously fried) is an RVC which should work (if wired correctly!).

So I'm hoping to pick up another RVC at a local auto jumble on Saturday, if I get no luck there I suppose I'll be visiting ebay or Spitfire Graveyard as I can't afford a fancy new one!

NOTE: Please don't take my wiring as gospel, all I'm saying is that with those connections it worked, not that it's how you're supposed to wire it up!

[john_classic]

Here's the wiring diagram I found on the web if anyone is interested  ;D

[Silvery]

How odd - One to coil, which makes sense, but then a 12v *and* a 12v ignition switched feed. Why does it need 2 12v feeds?

Just in case I come across one of these oddballs if I get a dash from a 2000 with the extra clocks, I'd love to know why it's done th way it is :)

[Tim Bancroft]

Stanpart 2000/2500 Manual:

1: Fused ignition controlled positive supply
2. Negative earth
3. From ignition controlled positive supply (Pulse lead)
4: To ignition coil via a ballst resistor

Sorry to be late replying.

[Richard B]

I think the two types work in quite different ways.

The early type of Rev Counter has the feed to the coil going through the rev counter. Thus Electronic Ignition will not make the needle work as there is not sufficient current to move the needle when EI is fitted.

The later type oof Rev Counter counts the pulses from the coil by having a tap from the feed. This is why it needs a separate 12v feed to move the needle.

Hope that makes sense (or have I got it completly wrong)?

Richard

[Crockett]

Hi,

I got a rev counter out of a 2.5 (I think) dashboard. This has only three connections (see attached). It says "RVC" on the dial.

(3) is obviously ground, as it's connected to the casing . (1) is a bullet type connector and the (2) is a spade type connector.

From reading the other posts, I would assume that the bullet connector (1) is for the 12v +ve feed (from the ign switch) and the spade connector (2) goes to one of the connections on the coil or the distributor CB connection?

I do have electronic ignition fitted so I guess I may need to experiment a bit with where to connect the pulse lead (whichever of the two connections that actually goes to).

I'll probably start by trying the distributor CB connection (-ve of the coil) then try the +ve of the coil, until it works.

Hopefully doing it this way will allow me to experiment without frying it. Hopefully if the +ve and ground connections are at least correct, this will not happen.

From what most prople have said, it looks like the +12v feed goes to the bullet connector (1)? Unless anybody can offer any advice or info?

Regards
Daryl.

[Crockett]

Hi,

Okay, with a little help from a multimeter and some trial and error, I have managed to get the rev counter working.

With regard to the image attached:

Connection 1 (bullet) goes to the contact breaker.
Connection 2 (spade) goes to the switched live.
Connection 3 (spade) goes to ground.

I have a "Lucas transistor assisted electronic ignition system" (Original? If not then fitted a while ago as it looks pretty old but works well) fitted and the rev counter works just perfectly.

Regards
Daryl.