Morris Minor Owners Club

hi there which is the best rev counter to get electric or manual and how do i fix one up to my morris with a 1098cc engine

a mechanical rev counter? i thought they were all electric and as for wiring them up it depends on the gauge you get, simply follow the instruction in the box.. the last one I fitted simply took a "feed" from the coil and a few other lines lights / earth etc


I think, having thought about your question..by mechanical do you mean a analogue gauge ( i.e. with a needle ) and electrical you mean a digital gauge. To answer that question is very simple, both work and an analogue gauge will be far more in period with the moggy but i fitted a digital gauge last as it was a great deal cheaper.

The only thing to make sure is that you buy a gauge for a 4 cylinder car for obvious reasons.. many gauges will allow you to change between 4 / 6 / 8 cylinders.

i have bought a old smiths electric rev counter with the needle for a 4 cylinder engine and just dont know how i wire it up

These threads might be useful:

http://www.mmoc.org.uk/viewtopic.php?f= ... ev+counter

http://www.mmoc.org.uk/viewtopic.php?f= ... ev+counter

Have a look here....... http://mk1-performance-conversions.co.u ... trical.htm

click on the smiths tacho and the complete smiths guide

Other interesting stuff there too

FOUND THIS WARNING ..... http://mk1-performance-conversions.co.u ... arning.htm

not sure what they mean by modern? ...modern cars or all elecronic ignition?

Hello Charlie,

there are a few cars about with mechanical tachometers, driven by a cable from the distributor, similar to a speedometer in action.

Jaguars used to have a generator connected to one camshaft which fed the tachometer, so one of those tachometers would not work by it's self.

Alec

Sprite Mk I had a mechanical drive taken off the back of the dynamo to run a tachometer. Personally I don't see the point in 'counting' the revs. What good will it do?

What "they" actually its I mean is ANY modern transistorised ignition system. These old Smiths instruments (the ones with the white coil of wire on the back) are ONLY designed for use with the original points & coil ignition system. he currents created by modern transistorised ignition systems thats Aldon Ignitors & the like will blow the old Smiths clocks to bits in seconds.

I hope that this makes sense.

Mark F
(MK1 PC)

Sprite Mk I had a mechanical drive taken off the back of the dynamo to run a tachometer. Personally I don't see the point in 'counting' the revs. What good will it do?

The MK1 Frogeye setup is excellent. Its a very, very expensive way of getting a rev counter though, the mechanical gubbins that I use on 1 of my cars was well over £500, it look s nice though.

There are many good reasons to "count your revs". If you have a standard car you can ensure that you are getting maximum fuel economy & the engine is working with minimum effort. But much more importantly on a highly tuned engine it helps you to stop blowing the whole thing up. I have a 999cc A series that revs to over 10,000 it picks up so fast that a tacho is the only real way of monitoring when you do or don't over rev it. I'll grant you this is probably not a major concern on the average Minor though.

Alec wrote:
there are a few cars about with mechanical tachometers, driven by a cable from the distributor, similar to a speedometer in action.

Alec

seems a very odd way of doing things but very interesting..

As for why would you want to fit one?

I fitted a tacho when i rebuilt the engine, i found it very useful to ensure that i took it easy / varied the revs when running it in.

I sold my 970 S engine to Morspeed - he put a BMW head on it, and shipped it out to Sri Lanka! My racing Mini (no - that's not it - that's the engine in Sri Lanka!) had NO 'revcounter' - there is no time to sit looking at instruments, I can assure you. It only had a LARGE orange light on a 15 psi oil pressure switch - no 'instruments' at all! I just revved it till it would go no more - then changed up. Seemed to work ok .......[frame][/frame]

Hello BMCE,

that may be the case for some engines, but my Triumph 2.5 will easily exceed the accepted limit which breaks the crank. I also bent the valves on another car I owned by exceeding the safe engine speed.
Certainly when racing it means that there is more things to watch so that's where a rev limiter comes in to ensure that engine damage is not experienced. Interestingly the first 2.5 P.I. Triumph introduced had a rev limiter as, I think, did the Lotus Twin Cam engine?

I do use mine to keep down engine speed when cold as well.

Alec

Alec - surely your natural mechanical sensibility tells you not to rev your 2.5 engine so hard! I don't think I have ever had my TR7 engine up to high revs - it runs nicely as a 'slogger'. As for keeping revs down when cold - you are not seriously telling me you need a 'rev counter' to tell you to do that.......... Yes - the Lotus Cortina Twin Cam came with a very simple rotor arm which had a spring loaded contact - too many revs and the contact pulled back away from the cap. Crude - but effective. I know of a case where the Escort version was sold to a young lad - who immediately removed that rotor arm, and 3 weeks later the crank broke. He tried to bring it back for money-back! And I'm sure that car had a 'rev counter' - so really - they are just a waste of space........... When revving the nuts off an engine - there really is no time to be watching a daft rev-counter!

Hello BMCE,

"surely your natural mechanical sensibility tells you not to rev your 2.5 engine so hard!"

It really picks up to 6,000 so easily in the lower gears and to tell between 6,000 and 6,500 is not so easy. No I don't need a rev counter but I find it pleasing to run up to 3,000 in the gears, each to his own. I'm sure you are aware that modern competition cars use lights to indicate the optimum speed to change up?

Alec

I can only assume that's because the drivers can't hear the engine - because they have their ears stuffed full of sound proofing!

Does that mean I shouldnt use my i-pod

Do you want an App with that?

i got luminatrix ignition and one of these rev counters will it work or blow

bmcecosse wrote: My racing Mini (no - that's not it - that's the engine in Sri Lanka!) had NO 'revcounter' - there is no time to sit looking at instruments, I can assure you. It only had a LARGE orange light on a 15 psi oil pressure switch - no 'instruments' at all! I just revved it till it would go no more - then changed up. Seemed to work ok .......[frame][/frame]

well it was my first engine rebuild and it cost me a lot of time and money and I needed the car for work.. but with a race engine you blow it up and if you can afford the rebuild you out for the rest of the season or until you can afford the rebuild i doubt my boss would have been too happy with me not turning up for work for a few weeks...

As for sound yes after it was run in i was more than happy to change up and down on sound but not during the running in period and with it being a 1300 A+ with marina / dolomite O/D box and marina axle i did not sound anything like the 1098 moggy that it once was. I also fitted oil pressure and water temp gauge so I could keep a close eye on what was happening

hotrodder13 wrote:i got luminatrix ignition and one of these rev counters will it work or blow

hotrodder my car had electronic ignition and the rev counter worked fine

thanks glad to know