I’m thinking the miles are clocking up faster than the actual miles traveled. As yet I’ve not tried to check if the miles shown traveled are the same as the actual miles done but I sense something isn’t quite right. Is this something others have come across? My 500L is fitted with a 650 126 engine and gearbox. I’m thinking maybe speedo drive as I see there’s different ones depending on if it’s for a 500 gearbox or a 126.
Technical Speedo drive?
- Thread starter MalcolmfromMoffat
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Technical Speedo drive?
the hobbler
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The speedo-drive units in the 500 and 126 gear-boxes ARE different due to the different final-drive ratios.It sounds as if you have fitted a 500's speedo-drive unit into your 126 gearbox.
Thanks Tom. I”ll have to take a closer look, the gearbox is just as I received it so I don’t know what speedo drive is fitted to it. I have another gearbox, a 500 fitment which has a speedo drive fitted so I’ll ratch it out and compare the two together to see if they are a pair.
Does the oil pour out if I remove the speedo drive? That’d be a nuisance! I’ll maybe need to find my ramps.
Does the oil pour out if I remove the speedo drive? That’d be a nuisance! I’ll maybe need to find my ramps.
that might require me to break out of my dinosaur egg!the hobbler
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If my memory is correct, oil will not gush out of your gearbox when you remove the speedo drive.
smart51
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My speedo has only a tenuous connection to the real world. While it is "calibrated" in km/h, the marks work better in MPH. 70 km/h = 40 MPH according to GPS. Each 10k mark = 6 MPH. So 50 = 28 MPH and 90 = 52 MPH. It means that for every 1 km/h the car says, it's only doing 0.92.
I've never checked if the distance is off by the same amount, but if it is, the odometer will read 8.7% higher than the true mileage.
I've never checked if the distance is off by the same amount, but if it is, the odometer will read 8.7% higher than the true mileage.
I thought it was fairly common, (at least in "the olden days"), to have the speedo factory-set a bit optimistically. I assume that wouldn't apply to the odometer. When calibrated against satnav readings, the most accurate speed reading my car ever gave was when I had a 126 box and speedo drive, with the bigger crownwheel and pinion from a BIS.
smart51
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The law demands that a speedo will never read less than the true speed, but may read up to 10% more. Given that new tyres are bigger than worn ones (obviously) that tyre pressures vary and cars can be empty or fully laden, speedos are set so that the worst case condition is still legal. In average use, they read a higher speed than you're actually doing. The 9% error of my car is pushing at the other end of the legal limit.
I'm told that in the days of the Sierra and Escort, Ford speedos were particularly low. Their dealers would sell you a different cog for your gearbox to make the speedo read a bit closer to your real speed.