4-cyl and 6-cyl rev counters - what is the actual difference?

[Danish 294]

I have in front of me two rev counters, one is for a 4 cylinder engine, one is for a 6 cylinder engine.

 

I've looked at the driver circuits and they're identical with the same layout and same value of resistors and capacitor. So what is the difference between them? I'm guessing the coil must be wound differently?

 

Edit: also, can you remove and re-fit the needles on a tacho?

Edited June 4, 2016 by Danish

[do it sideways 41]

Just calibration,,

[Danish 294]

Thanks Steve. Is it possible to re-calibrate?

[John Mack 286]

Try Speedy Cables, pretty sure they do recalibration?

[Danish 294]

Try Speedy Cables, pretty sure they do recalibration?

 

They seem to do speedo calibration at least, but I'd rather do it myself.

 

Having thought about it for 24 hours, if DIY calibration isn't possible, I might design a new driver circuit - remove the Ford electronics and hook up my own micro-processor to drive the needle directly.

[Pete-H 66]

They seem to do speedo calibration at least, but I'd rather do it myself.

 

Having thought about it for 24 hours, if DIY calibration isn't possible, I might design a new driver circuit - remove the Ford electronics and hook up my own micro-processor to drive the needle directly.

 

Jayne

 

If you design your own driver circuit would it be a for any electronic rev counter or just Mk4/5 rev counters?

[Danish 294]

If you design your own driver circuit would it be a for any electronic rev counter or just Mk4/5 rev counters?

 

What I had in mind would work for the 'generic' Ford tacho which seems to have been fitted in a few formats through the the mid-70s to mid-80s on Cortina/Capri/Escort/Granada.

 

But once it's working I can send you one to try on a different make.

[Pete-H 66]

What I had in mind would work for the 'generic' Ford tacho which seems to have been fitted in a few formats through the the mid-70s to mid-80s on Cortina/Capri/Escort/Granada.

 

But once it's working I can send you one to try on a different make.

 

Please :thumbup:

[Danish 294]

Please :thumbup:

 

No problem. :thumbup:

[sheffieldcortinacentre 610]

needles can be pulled off, speedy cables will re-calibrate.

 

what ever it is , is in the gauge, you need to have a look inside one of the switchable ones as they do 4/6/8 cyl have one in the V8.

[do it sideways 41]

The Ford tacho is adjustable

[MK5CortinaEstate 52]

My V6 rev counter had a twiddly pot on the back. I used it to adjust mine to read right with the V8.

[Alpina 0]

I'm looking to find a way to make my V6 rev counter start working again as my car has electronic ignition fitted?

 

Wiring direct to the coil has only produced a very weak reading.

[Pete-H 66]

I have a similar problem on my V4 Corsair the electronic ignition is not putting out a powerful enough signal for the Tacho detect it and register the impulse Jayne will sort it but it may be a little wait but it will be worth it I'm sure of that.

[Danish 294]

My V6 rev counter had a twiddly pot on the back. I used it to adjust mine to read right with the V8.

 

MM3 loaned me a PFL one today and yes, it has a 4k7 pot on the circuit board. So it might be that our new circuit will only be needed for facelift gauges, or PFL ones with broken circuit.

 

I'm looking to find a way to make my V6 rev counter start working again as my car has electronic ignition fitted?

 

Jayne will sort it but it may be a little wait but it will be worth it I'm sure of that.

 

We're building a prototype at the moment, once that's working we'll be looking to get a batch of circuit boards made up. But, it's not obvious at the moment how to make these available as the board will need calibrating to the engine and gauge - the prototype needs a special USB cable and software to programme a calibration value from a PC or Mac. Maybe we can add '+' and '-' buttons onto the board or something... watch this space.