13 replies to this topic

[tekon1984]

Hi there,

I've recently bought a pukka little mini sprite, but it's riddled with problems which I'm sorting out one by one.

The biggest problem right now is that it has almost cost me my license due to clocking the wrong speed on the speedometer. I know that it feels like you are travelling alot faster in a mini because of the lower ride and harsher suspension, so thought nothing of it. But then I received two speeding tickets, 6 points and have been "invited" to do a drivers awareness course. !!! All fines were issued by the same camera in a 40 zone but I was travelling at 48-49/mph, thinking I was at 40.

So, having received these tickets, I went out following a pal last night whilst staying in constant contact and it turns out that my speedometer is out by roughly 10/mph at the low end and almost 15/mph at higher speeds. i.e. when I think I'm doing 30, I'm actually closer to 40 and when I'm doing 60 the clock says approx. 45/mph. With this, my first idea was to get the speedo dial out and take a magic marker and some tip-ex to it. Just to be certain, we went out for another run but the results were slightly different. Having done this a few times, we came up with inconsistent results.

All in all, I'm at a loss with how to fix it. The car is a 1275 Sprite but it has a 1275 A+ engine from a metro. I'm not sure about the gear box though. When I first got it, i took it round to my friends to fiddle with it (he has tools, I don't) and the speedo cable slipped out of its location on the gearbox just by moving it out of the way of the carb. I was given a new cable with the car but a. it was too short and b. it had the wrong connections on it

There is all the details of the problem. Question is; How can I fix it? Do I go for the cheap but nasty looking, in-accurate option of the tip-ex and marker pen? Different speedo cable? Different speedo fascia? Maybe even a new digital speedo?

Annoying thing is, I've been driving for 5 years with a clean licence, no points or endorsements... and now this.

Any and all suggestions on how to rectify the issue at hand will be greatly appreciated. Also, if anyone has any advice on whether I should appeal against the fines or if it would be a waste of time, that would be great too.

Thanks for reading

Nick

[andy159]

you could buy a really cheap sat nav which displays ur speed and use that but would be a pain taking it in and out all the time. im not a mechanic but replacing the cable would be a good idea im sure someone will post shortly with a better answer as to whether a damaged cable could have this affect. Does the rev counter work ok though? as you could use that to calculate your speed ie 2500 rpm in 4th gear is 30 mph approx 3000 rpm is 45 etc.

[Carlos W]

I downloaded an App for my HTC phone which shows my speed, but it sounds like the cable may be a good place to start!

I don't think you'll get far appealing, they'll probably do you for having a faulty speedo! Citizens advice will be able to give you a better idea though!

[1995 MK2 IOM]

I had a similar problem...

Do you know the history of your engine? i.e. was it built for the European market?

It could be something to do with that?

My problem was slightly different, the odometer was running too fast... i.e. was showing I was doing more miles than I was... but I found out that the engine was set up for KPH so the odometer was running round every KM not each mile... (its still doing it but I just know about it now! so have to convert it...

I dont know whether that would affect the speedo though?

J

[Tommyboy12]

Mine massively under reads. Says im doing 50mph when im doing 75mph. Its to do with the turns per mile of the instrument cluster as well as the worm and pinion drive in the gearbox. Because your engine is from a Metro it will have a different worm and pinion ratio to go with the tpm of the cluster from a Metro. So now its in a Mini its wrong. Only way to change it is to have the gearbox out. Ive personally got a little printed sticker stuck next to the speedo to remind me.

[tekon1984]

you could buy a really cheap sat nav which displays ur speed and use that but would be a pain taking it in and out all the time. im not a mechanic but replacing the cable would be a good idea im sure someone will post shortly with a better answer as to whether a damaged cable could have this affect. Does the rev counter work ok though? as you could use that to calculate your speed ie 2500 rpm in 4th gear is 30 mph approx 3000 rpm is 45 etc.

I only have the two dials. Speedo and fuel/temp. Not a bad idea though.

I'm not a satnav user. Personally, I'd rather read a map and get myself lost than have a machine do it for me. I see driving as an adventure. I'll never have a satnav in my car. Again, not a bad idea.

Thanks for your input.

[andy159]

you could buy a really cheap sat nav which displays ur speed and use that but would be a pain taking it in and out all the time. im not a mechanic but replacing the cable would be a good idea im sure someone will post shortly with a better answer as to whether a damaged cable could have this affect. Does the rev counter work ok though? as you could use that to calculate your speed ie 2500 rpm in 4th gear is 30 mph approx 3000 rpm is 45 etc.

I only have the two dials. Speedo and fuel/temp. Not a bad idea though.

I'm not a satnav user. Personally, I'd rather read a map and get myself lost than have a machine do it for me. I see driving as an adventure. I'll never have a satnav in my car. Again, not a bad idea.

Thanks for your input.

its just to use for the gps speed though as a cheap gps speepometre, but yes they are evil machines

[tekon1984]

Mine massively under reads. Says im doing 50mph when im doing 75mph. Its to do with the turns per mile of the instrument cluster as well as the worm and pinion drive in the gearbox. Because your engine is from a Metro it will have a different worm and pinion ratio to go with the tpm of the cluster from a Metro. So now its in a Mini its wrong. Only way to change it is to have the gearbox out. Ive personally got a little printed sticker stuck next to the speedo to remind me.

My friend suggested that last night and that's how I came up with the tip-ex and marker idea. But still the reading is so inconsistent that I'd rather get it fixed so that it is accurate.

Seems you may be right with the gearbox as that was my first thought. Costly though.

Thanks for your input.

Nick

[1995 MK2 IOM]

could you not put a metro clock in? surely that would work?

J

[tommy13]

Changing the cable will have no effect at all. The diff and speedo drive worm and pinion in the gearbox may be different in the Metro engine than those of the Sprite, and so not geared to give the correct reading on your speedo head.
Guessworks is a member on here and has a useful website for solving this problem. First you need to know th TPM (turns per mile) of the speedo head and also the diff ratio and other information . First look here.
http://www.guess-wor...Tech/speedo.htm

Then put this into the calculator here along with the other info to find the correct worm and pinion to make the speedo read correctly.
http://www.guess-wor.../Tech/ratio.htm

Another possibility is to have the speedo head recalibrated, but I have no idea where.

Edited by tommy13, 09 January 2011 - 12:12 PM.

[amarcd]

Speak to Guessworks, I had the same problem and all you need to do is change the worm and pinion for the speedo drive, you can do it with the engine in you just need to take the rad, and undo that engine mount and jack the engine up a bit to slide the pinion. I can be done!

[david@skeggyminis]

or you could send the clocks to http://www.speedycables.com/

[Sleepy Stu]

As everybody has said above the clocks are not calibrated correctly for the new engine. So you either correct the worm and pinion or you send your clocks of and get them corrected.

Also worth considering what size are the wheels on the car?

[secondopsman]

or you could send the clocks to http://www.speedycables.com/

Mines there now for the 16v conversion its £55 so cheaper than a speeding ticket.
pete