Speedometer Sigma 2009

[Tuck2020]

Please be gentle, this is the first of many, many novice questions.

 

My ex academy car appears to have no speedo sensor fitted on any hub, and I can't find one on my gearbox (although I'm not entirely sure what I'm looking for, although google has helped). Therefore I'm starting to think my car hasn't got one, and that the race kit (vbox etc) was the source of speed info.

The speedometer shows the mileage with the ignition on, and the needle twitches slightly when I turn the ignition on, so I assume power is not the issue. 

I have had the car raised slightly, and having crawled underneath (not an easy task with lowered floors and a lockdown beer belly) I can see a couple of wires dangling down to the gearbox, but nothing obvious that they would connect to. So, in layman terms if you please;

 

Is it possible my car has never had a speedo fitted? It's always been a race car.

Am I looking in the wrong places? Could someone point me in the right direction?

What do I need to rectify the situation?

 

All advice gratefully received. Many thanks 

 

[K7 VCT]

Guess the wires are for reverse light switch .

As you will have a ford gearbox, speedo is a cable drive unit not electrical ?

The drive is an angle drive, which maybe the issue.

Sure someone will soon confirm.

[Jonathan Kay]

Private Message sent.

Jonathan

[Tuck2020]

Thanks everyone, in particular for the detailed PM and guide, I'll work my way through it. I'll check reverse lights etc and report back.

In relation to the transmission tunnel hole, ive already had a look and taken a picture on my phone, I'll add it.

[Scotland North AR]

Mine is a 2009 Sigma and has the speed sensor gear on the driver's side hub. It may be that the speed sensor itself is not fitted. You could take a picture of the drive'r sid hub from the front and it can be marked up what you are looking for.

[Tuck2020]

[Tuck2020]

Thanks Nigel. Following a bit of web research I haven't found anything resembling one on my car anywhere.

[Garth]

Sent you pm

[John Vine]

Welcome.  And fear not, we're always gentle here!

You say your speedo shows the mileage.  Does this increase on the road or simply show the same value all the time?

The speedo on a road car of your year would normally be driven by a sensor adjacent to the outer end of the RH driveshaft.  The sensor is mounted on a bracket, the shape of which depends on whether or not you have a rear anti-roll bar (ARB):

From the Assembly Guide:

With ARB:

Without ARB:

Also, is there a connector emerging from the wiring loom close to the hub shown above?  If so, it could be that all you need is the bracket and sensor.  Photos of the hub and nearby wiring loom would help us advise.

JV

[Matthew Willoughby]

My car is also ex 2009 Academy. I agree that the speedo sensors were on the nearside rear hub and would have been required for the IVA. Race cars always seem to have them disconnected but I don't know why. My sensor is missing from the ARB bracket but it's a 10 year old car that has never been MOT'd which tells you how much road use it's had. The mileage has read just over 3,000 for many years I suspect. I have a GPS Speedo on my lap timer that I can use if necessary.

[Tuck2020]

Thanks everyone. No sign of a serrated disc, sensor bracket or sensor at all on my hubs. It's always been a race car, not mot'd until last week (when it may well have still had the vbox etc fitted). In relation to the mileage increasing I'm afraid I didn't take note, and I'm reluctant to take it out without a speedo, even if I avoid the towns there are plenty of camera vans around here. I'll whip the wheels off and take photos between rain showers in case I'm missing something obvious.

[Tuck2020]

offside rear. Am I looking in the right place?

[John Vine]

Yes, you're looking in exactly the right place.

This is where the serrated (reluctor) ring would normally be:

You can see it here.

I don't know whether you could retrofit one, but my guess would be yes.  No doubt someone who's done it will be along shortly.

JV

[Tuck2020]

Thank you John. 

[Garth]

You could download a 'speedo app' on a smartphone and use that for the timebeing? 

[Tuck2020]

Thanks Garth, funnily enough I did that this afternoon.

[Tuck2020]

So, could anyone point me towards my next course of action please?

My guess is that I need to trace the wires from the rear of the speedometer and see where they terminate? Then what? Is it a case of deciding if I want a hub mounted, or gearbox sensor, and sourcing the relevant parts, or am I over simplifying things to a great degree?

As you have probably guessed by now, I am very much a novice, however I am thoroughly enjoying myself!

 

Any thoughts would be most welcome.

[John Vine]

No, I don't think you're over-simplifying things.  The age and model of your car suggests that the best solution would be to go for a driveshaft-driven speedo, matching the factory spec.  Of course, this assumes that the car has the factory-supplied sensor loom in place.

First, check whether there's a 3-way Econoseal connector just above the rear ARB chassis mounting clamp, near the front of the O/S wheel arch:

This might be tied up out of the way, but should look like this:

If there isn't one, we'll need to think again.  But if there is, you're in with a good chance of getting a working speedo.

You'll then need:

• A 43-tooth reluctor ring attached to the RH driveshaft.  I don't think CC sell these separately, but there are probably other sources.  You could always ask CC if they know of one.
• A mounting bracket for the sensor. This will attach to the de Dion ear where your hexagonal extension piece is at the moment.  See photo 1 in #9.
• A second bracket (possibly) for the N/S ARB link mounting.  This is to keep the two ARB arms properly aligned.
• A sensor

If you can't locate a reluctor ring, you always have the (pricey) option of buying a complete RH driveshaft.

Let's hope you find the connector.  Post up a photo, if possible.

JV

 

 

 

 

[Tuck2020]

Very useful, thank you. I will report back.

[aerobod - near CYYC]

The reluctor ring is probably from a Rover: http://www.carsparesdirect.com/rover-25-45-400-abs-reluctor-ring-43-teeth.html

Should be able to confirm the diameter from the shoulder on the driveshaft. The shoulder should be rust free, then heat the ring in the oven at 250C for 10 mins or so and have the shaft nearby when it comes out of the oven. Should slip right on and cool to a tight fit.

[Tuck2020]

That's fantastic, thank you. I had been browsing full drive shafts and wincing at the price! That looks a much nicer alternative!

John, in regards to your thoughts about the econoseal connection, I think I may have located one tucked up between the boot and the offside wheel arch. It's cable tied up out of the way, I'll cut the tie tomorrow and see what's there.

Thanks everyone for your input.

[aerobod - near CYYC]

Just looking at my car and other images, it seems the Rover reluctor ring may have the right number of teeth, but the ring inner diameter looks to be larger, the Caterham ring looks to be beefier overall. It may be a custom ring for Caterham, unfortunately.

[Tuck2020]

Thanks James. 

[Tuck2020]

Ok, so a little update for anyone who this may benefit.

I located an econoseal connector which was cable tied up out of the way in the recess between the boot and wheel arch. With lots of help via messenger, from  John Vine and Jonathan Kay, it appears that this is the part of the circuit where the speed sensor would plug in. The next suggestion was to check with a multimeter to see if it is receiving power. The probes on mine were far too fat to fit in, but I got around this by inserting a split pin into the socket and testing each hole in turn. The middle hole is registering power at 11.8. So that's a good start.

 

I also managed to speak to Chris at Redline today , who informs me that the reluctor ring is not a part that they carry in stock. He suggested trying to find a scrap driveshaft to butcher. He really went out of his way to help me which confirmed everything that I'd heard about the company.

If anyone happens to have a driveshaft on the bench that can confirm accurate sizes required for the reluctor, I'd be grateful if they could post them here, to help anyone in future with the same issue?

John and Jonathan suggested that I revert to posting here as opposed to using messenger, which makes sense. Thanks to all for your input so far, every step is a step closer to getting me on the road. I'll be posting wanted ads for various bits and pieces shortly!

[John Vine]

Hi Adrian,

As I mentioned in my PM, I've asked CC whether they can either supply a reluctor ring as a separate item or suggest where to get one.  I've also asked them to recommend any other parts you might need (sensor, brackets etc).  I'll post up their reply.

While we're waiting, it would be worth checking the calibration code on your speedo.   Its existence would give you a good idea of whether the car was built with a working speedo.

See Part C in this Guide.

Also, what size tyres does the car have?

JV