The 'E' Type Forum

This one is blowing my mind a bit as I can't get my head around it, so any help appreciated please!

It appears that my 'odometer' is registering a different amount of miles travelled to my 'tripometer' and that (although I haven't proved it for definite yet I think the trip reading is the correct mileage.

Today, having filled up with fuel, I reset the trip and at the end of my journey the trip was showing 75 miles travelled and yet the odometer was showing 50 miles travelled.

I thought that the 2 were linked and only driven by one cable.

Also, does anyone know the correct 'ratio' for a 1967 Series 1 OTS 4.2 or part number I need if I have to replace it.

Thanks

Graham Maunder
07831 515678

John Ostick is the man.

He has fixed and re-calibrated some speedos for me, very quick reliable and well priced service.

john_ostick@hotmail.com

www.jdo1.com

There should be a number on the speedo face starting S/N and this relates to the diff ratio and mph/kph. You can find a list of all the speedometer numbers here: http://forum.etypeuk.com/viewtopic.php?p=8141#p8141

Thanks for the quick reply.

My speedo is showing S/N 6322/03A, which according to your list seems correct (series 1, 4.2 OTS early 1967) with 185VR15 Dunlop SP tyres.

Still not sure on the inconsistency between odometer and tripometer though....

You have a 3.31 diff?

Heuer

How can i check this for sure? It should be 3.31 but is there an easy way to check this (apart from on paperwork?).

Also, even if the speedo is wrong for the diff, surely the odometer and tripometer should be consistent to each other?

Thanks for your help.

Graham

Hi Graham....as you realise already the speedo is driven by one cable so inconsistancy between trip and odometer will be a problem with the speedo......to check your diff ratio jack up the rear of the car.....turn the i/p shaft (prop) and count the o/p shaft...wheel....for a 3.31 its 3.31 revs in to 1 rev out......Steve

Thanks for the help Steve - will double check the diff on my return from the Revival weekend and arrange to get the speedo serviced.
Graham

Checked a few things on the journey back and travelling at an (indicated but verified by the sat nav) steady 60mph for a minute the tripometer did indeed show a mile travelled but it took 1min 30secs for the odometer to show a mile travelled.

Graham

There should be a tag on the diff stating the ratio (as a fraction), in this example a 3.54:

It sounds to me as though either the trip odometer or the main odometer has been changed for one from a different speedometer. Each odometer has an independent gear set, and ones for mph and kph use different ratios, as do various speedos for different axle ratios. I very much doubt that your car has a 3.31 unless it was a special order car. Virtually all S1.5 for the UK had 3.07, and thus the problem may be compounded by you having in incorrect speedo for the axle ratio, or even a "bitsa" speedo/odo/trip melange.

There is a very good article on Smiths speedos by Anthony Rhodes .the link for which is

http://obswww.unige.ch/~wildif/cars/doc ... repair.pdf

Christopher
Thanks for you reply and the link.
My car was originally a LHD exported to USA and was changed to RHD 20 years ago.
I'll double check the diff ratio though and take it from there.
Graham

Ah ! if yours is a 1968 USA spec car, then the likely axle is 3.54 which will have the 46/13 tag on it . The probable original speedo for this is SN 6322/37 and at a guess the turns per mile would be 1312 or something very close to that

Thanks again Christopher

The car is actually an early 1967 model that started life as a LHD.

I'm away for work now so haven't been able to check the diff but will loo when I return home and update on here!

Graham