Rev Counter

[russ spake]

Chaps, need your help please with my 1972 Mk1 which has a Rover V8 fitted. The rev counter used to work fine, then started twitching about with no accurate read on the revs and finally stopped. I bought a good condition replacement but there's no sign of life. The light works as it should with all the other dash lights, the engine stops when you disconnect the dialbut the needle doesn't move.

As you'll probably know there's a fair number of wires in the back of them and I was wondering whether there's a power feed in addition to the circuit with the coil which powers to dial whichhas failed. If so, how do I test it and how do I test whether the second rev counter I've bought is working properly - other than putting it in another car!? Appreciate any help, thanks. Russ

[stoutgoose]

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Do you have electronic ignition fitted?

If you have, then you need to get the rev counter rewired to cope properly with modern electronics. You currently have 4 wires in the back. This will be reduced to 3. Two of the wires are part of the ignition circuit (I can't remember from memory which ones, but light green rings a bell), and as you mention, when you disconnect them, the engine cuts. You can wire these together to complete the circuit and bypass the rev counter; this is basically what 'speedy cables' (see below) will tell you to do. Their remaining wires will run to + and - on the coil and to earth.

Try 'speedy cables'. They sorted mine out for about £50. It had exactly the same symptoms as yours, as did the replacement, until fixed. They also supply wiring instructions for refitting.

If you don't have electronic ignition, using a wiring diagram, you'll need to trace and check wiring connections, earths, etc.

[mad cyclist]

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russ spake wrote:

Chaps, need your help please with my 1972 Mk1 which has a Rover V8 fitted. The rev counter used to work fine, then started twitching about with no accurate read on the revs and finally stopped. I bought a good condition replacement but there's no sign of life. The light works as it should with all the other dash lights, the engine stops when you disconnect the dialbut the needle doesn't move.

As you'll probably know there's a fair number of wires in the back of them and I was wondering whether there's a power feed in addition to the circuit with the coil which powers to dial whichhas failed. If so, how do I test it and how do I test whether the second rev counter I've bought is working properly - other than putting it in another car!? Appreciate any help, thanks. Russ

purist will tell you it's just what happens when you fit a rv8 in a stag, things start to look a little ragged and then start to pack up, just when you think it cannot get any worse the car will go in to John Hurt type convulsions and the 'alien' will burst out of the bonnet through your garage door, and run along on it's ht leads looking for a tvr to infest............apparantly

[StagnJag]

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mad cyclist wrote:

russ spake wrote:

Chaps, need your help please with my 1972 Mk1 which has a Rover V8 fitted. The rev counter used to work fine, then started twitching about with no accurate read on the revs and finally stopped. I bought a good condition replacement but there's no sign of life. The light works as it should with all the other dash lights, the engine stops when you disconnect the dialbut the needle doesn't move.

As you'll probably know there's a fair number of wires in the back of them and I was wondering whether there's a power feed in addition to the circuit with the coil which powers to dial whichhas failed. If so, how do I test it and how do I test whether the second rev counter I've bought is working properly - other than putting it in another car!? Appreciate any help, thanks. Russ

purist will tell you it's just what happens when you fit a rv8 in a stag, things start to look a little ragged and then start to pack up, just when you think it cannot get any worse the car will go in to John Hurt type convulsions and the 'alien' will burst out of the bonnet through your garage door, and run along on it's ht leads looking for a tvr to infest............apparantly

Mad C. you are on form tonight! lol

Dave

[stustag]

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mad cyclist wrote:

russ spake wrote:

Chaps, need your help please with my 1972 Mk1 which has a Rover V8 fitted. The rev counter used to work fine, then started twitching about with no accurate read on the revs and finally stopped. I bought a good condition replacement but there's no sign of life. The light works as it should with all the other dash lights, the engine stops when you disconnect the dialbut the needle doesn't move.

As you'll probably know there's a fair number of wires in the back of them and I was wondering whether there's a power feed in addition to the circuit with the coil which powers to dial whichhas failed. If so, how do I test it and how do I test whether the second rev counter I've bought is working properly - other than putting it in another car!? Appreciate any help, thanks. Russ

purist will tell you it's just what happens when you fit a rv8 in a stag, things start to look a little ragged and then start to pack up, just when you think it cannot get any worse the car will go in to John Hurt type convulsions and the 'alien' will burst out of the bonnet through your garage door, and run along on it's ht leads looking for a tvr to infest............apparantly

Is this not what happens then?:?If you fit a Jag V8 does it do the same but looks for an Aston Martin?

Stuart

[russ spake]

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Thanks stoutgoose, I do have electronic ingition so I'll follow your recommendations - much appreciated.

Mad c, just laughed out loud, great response. Look forward to passing you by on the verge, don't worry though I've got plenty of power and torque to towyou to the nearest specialist to get you back on the road again! It's a good job BLdidn't use theRV8 orginally, just think how little we'd have to talk about - besidesthey'd havebuilt so many Stags that they wouldn't have their exclusive appeal.

Happy motoring all!!

[stoutgoose]

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StagnJag wrote:

mad cyclist wrote:

russ spake wrote: purist will tell you it's just what happens when you fit a rv8 in a stag, things start to look a little ragged and then start to pack up, just when you think it cannot get any worse the car will go in to John Hurt type convulsions and the 'alien' will burst out of the bonnet through your garage door, and run along on it's ht leads looking for a tvr to infest............

.....or maybe a yellow Stag owned by an illusive fellow who hides his identity behind a rubber mask!

[V Mad]

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russ spake wrote:

Chaps, need your help please with my 1972 Mk1 which has a Rover V8 fitted. The rev counter used to work fine, then started twitching about with no accurate read on the revs and finally stopped. I bought a good condition replacement but there's no sign of life. The light works as it should with all the other dash lights, the engine stops when you disconnect the dialbut the needle doesn't move.

As you'll probably know there's a fair number of wires in the back of them and I was wondering whether there's a power feed in addition to the circuit with the coil which powers to dial whichhas failed. If so, how do I test it and how do I test whether the second rev counter I've bought is working properly - other than putting it in another car!? Appreciate any help, thanks. Russ

Just out of interest, I am working on a RV8 Stag fitted with Lumenition, and the rev counter leaps around all over the place.

The reason this happens is that the electronic ignition can produces spikes whichinterfere with the instrument, andin theory this could also happen with the Stag V8 engine.

I fitted a filter into the ignition feed (white)wireand the reading is now accurate andsteady as a rock.

[polly]

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:?

[StagnJag]

imported post

mad cyclist wrote:

russ spake wrote:

Chaps, need your help please with my 1972 Mk1 which has a Rover V8 fitted. The rev counter used to work fine, then started twitching about with no accurate read on the revs and finally stopped. I bought a good condition replacement but there's no sign of life. The light works as it should with all the other dash lights, the engine stops when you disconnect the dialbut the needle doesn't move.

As you'll probably know there's a fair number of wires in the back of them and I was wondering whether there's a power feed in addition to the circuit with the coil which powers to dial whichhas failed. If so, how do I test it and how do I test whether the second rev counter I've bought is working properly - other than putting it in another car!? Appreciate any help, thanks. Russ

purist will tell you it's just what happens when you fit a rv8 in a stag, things start to look a little ragged and then start to pack up, just when you think it cannot get any worse the car will go in to John Hurt type convulsions and the 'alien' will burst out of the bonnet through your garage door, and run along on it's ht leads looking for a tvr to infest............apparantly

Sounds like Krytens aliens have come out of hibernation and are back to work again!

[maverick]

imported post

V Mad wrote:

russ spake wrote:

Chaps, need your help please with my 1972 Mk1 which has a Rover V8 fitted. The rev counter used to work fine, then started twitching about with no accurate read on the revs and finally stopped. I bought a good condition replacement but there's no sign of life. The light works as it should with all the other dash lights, the engine stops when you disconnect the dialbut the needle doesn't move.

As you'll probably know there's a fair number of wires in the back of them and I was wondering whether there's a power feed in addition to the circuit with the coil which powers to dial whichhas failed. If so, how do I test it and how do I test whether the second rev counter I've bought is working properly - other than putting it in another car!? Appreciate any help, thanks. Russ

Just out of interest, I am working on a RV8 Stag fitted with Lumenition, and the rev counter leaps around all over the place.

The reason this happens is that the electronic ignition can produces spikes whichinterfere with the instrument, andin theory this could also happen with the Stag V8 engine.

I fitted a filter into the ignition feed (white)wireand the reading is now accurate andsteady as a rock.

Chris,can you elaborate on the filter please.

Thanks Mark