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Recallibrating the speedo
Posted: Wed Sep 03, 2008 12:27 am
by Sidney'61
..How hard is it to do?
My speedo needs recalibrating for the 1275 engine etc...
Can this be done at home? or if not where can you recommend I get it done?
Thanks
Posted: Wed Sep 03, 2008 1:57 pm
by bmcecosse
Well - fitting a 1275 engine makes absolutely no difference to the speedo - so what else have you fitted ? If you fitted a Spridget gearbox - it has different speedo drive gears in there, and yes you will now need a different speedo. Likewise -a diff ratio change will affect the speedo. What's the speedo reading when you are trailing along behind some trucks doing 56 mph ? Easiest change is to fit a different speedo - with a more suitable 'tpm' to get the speed reading nearer the truth - so, look at your speedo and see what the tpm number is. It's in small print on right hand side just below the mileometer readout.
Posted: Wed Sep 03, 2008 2:48 pm
by PSL184
Andy, I think it will be the Sierra 5 speed g/box that is giving a false speed reading. You will need a different drive gear from the speedo to fit the box. Try to find one that fits a Ford with the same ratio back axle as in your Moggie....
Posted: Wed Sep 03, 2008 3:34 pm
by bmcecosse
Ahh - 5 speed box. But if you know the difference in the speedo reading from the correct speed - and the tpm of existing speedo, then it's easy to work out tpm needed to get the correct speed and mileage - and then start searching for a suitable speedo with near to that tpm.
Posted: Wed Sep 03, 2008 3:39 pm
by PSL184
True - just thought it maybe easier to change speedo drive though. Most ford boxes use the same drive system and there must be thousands of combinations out there!
Posted: Thu Sep 04, 2008 6:14 pm
by Sidney'61
We tested it following my brothers car and it seems to be about 5mph at all speeds, so its a not a major problem but it would be nice if it was right!
I think the ford drive gear may still be out due to the 1098 axle?
Posted: Thu Sep 04, 2008 6:17 pm
by bmcecosse
I would say 5mph is pretty good - stick with it!
Posted: Fri Sep 05, 2008 9:04 pm
by WPR678B
bmcecosse wrote:I would say 5mph is pretty good - stick with it!
Thats what i thought and soon got used to it!
Posted: Fri Sep 05, 2008 10:30 pm
by Dominic
This chap, John Ostick, did a great job of repairing my speedo. Very fast service and reasonably priced. He also does re-calibrations.
http://www.jdo1.com/index.html
Dom