Incorrect Speedo

Post by **jmcar** » Thu Sep 29, 2005 8:34 pm

I know this has been bandied about before but I've looked at all the obvious and now I'm stumped.

I have a '68 Traveller with a 1275 Marina engine, original 1098 gearbox, original 1098 diff and axle, original 155/14 wheels and tyres.

Having said all that, my speedometer reads 70mph when I'm actually only doing 60mph. Whilst this is great for avoiding speeding tickets, it's a bit annoying. Can anyone shed any light on what this would be other than just a knackered speedo?

Post by **ColinP** » Thu Sep 29, 2005 9:53 pm

Hmm,

Possibly a replacement speedo with the just wrong calibration?

Easiest thing is to search here for the sppedo service guy.

Colin

Post by **Willie** » Fri Sep 30, 2005 2:44 pm

What is the serial number on the face of your speedo beginning
SN....... and what is your chassis number(just the numerals not
the prefixes).

Post by **jmcar** » Sat Oct 01, 2005 1:59 pm

Chassis Number is MAW5D 1209582 and the serial number on the speedo is SN-4423/04

Post by **Willie** » Sat Oct 01, 2005 3:32 pm

OH!...your chassis number is correct for a late Traveller but 'the bible'
says that the speedo number would be SN4423/06, not much of a
difference but do not know why the discrepancy. Suggest you have
it recalibrated by the specialists.

Post by **jmcar** » Sat Oct 01, 2005 5:33 pm

Thanks for the info. It does indeed look like my only option is to get the unit re-calibrated. Out of interest, where do you find this info? What is this 'bible' you speak of? I've only got my traveller in the past 6 months and there appear to be quite a few non-standard parts. Such a reference would be very handy!

Post by **Willie** » Sun Oct 02, 2005 5:43 pm

Apart from,obviously, the official Workshop Manual you should
buy a copy of 'Original Morris Minor' by Ray Newell and, if possible
'The Worlds Supreme Small Car-Morris Minor' by Paul Skilleter.

Post by **Matt** » Sun Oct 02, 2005 9:33 pm

Have you got the standard diff?

Post by **jmcar** » Tue Oct 04, 2005 7:45 am

Sure have. I had to replace the rear axle casing the other week so the diff had to come off. It is a 9/38 diff which I believe is standard on the 1098 traveller.

Post by **Willie** » Tue Oct 04, 2005 6:33 pm

Yes, 9/38 = standard 4.22-1 on the late Traveller.

Post by **Onne** » Tue Oct 04, 2005 6:37 pm

where doe you find that number? This because I finally want to know for sure what I have.

Post by **Willie** » Tue Oct 04, 2005 6:46 pm

If you mean the diff number 9/38 it is on the edge of the crown
wheel.

Post by **Onne** » Tue Oct 04, 2005 7:01 pm

Oh, so you need to open up then....

Post by **Willie** » Tue Oct 04, 2005 8:17 pm

ONNE.. I have read that the diff ratio is stamped somewhere
on the outside of diff housing but have never seen this and
would imagine that it would be difficult to see unless the
unit was off of the car and energetically (can't spell vigorously)
wire brushed.

Post by **Onne** » Tue Oct 04, 2005 9:41 pm

I won't bother then. Let it be.

Post by **Cam** » Tue Oct 04, 2005 10:34 pm

If you have the diff out the easiest way is to count the teeth on the crownwheel (should be 38 ) and the pinion (should be 9).

Onne, if you need to know your ratio, then you can test it by jacking one rear wheel off the ground, marking the prop and noting down how many complete turns of the prop there are for a certain number of wheel turns.

Take the 1098 (4.22:1) diff as an example.

If BOTH rear wheels were off the ground then the rear wheels should turn 9 times for 38 prop turns. If ONE rear wheel is jacked up then it should be 18 turns of the wheel for 38 prop turns.

But I don't think you have a 4.22 diff do you? do you have the series 2 type?

Post by **Onne** » Wed Oct 05, 2005 6:46 am

Nope an LCV one. So 4,55 it is. absolute top is about 70mph on the clock, 115kph according to the satnav.
And she is screaming like mad then.

Post by **bigginger** » Wed Oct 05, 2005 11:09 am

That'll be the 4.55:1 all right...

A genuine question - when did the axle ratio change for saloons? I remember reading that at one point 4.45:1 was standard across the range and later changed for all but LCVs...

Post by **richard.baker707** » Wed Oct 05, 2005 8:47 pm

hi guys could i grab onto the thread as i would like some info on ratios.
from what i've read a 4.55:1 gives u a low top end and a 4.22:1 is better is there any other ratios available?
I have a '57 2dr 948 {although next week i'm getting an 1098 and gearbox for £30 sounds better than my 948} which i use on the motorway everyday but would like to improve top speed.
also do taller tyres affect the speedo reading i have 6x14 minilight replicas on the back with 185/70/14 these are approx 24"from road to top of tread. thanks for any advice.
Rich

Post by **Cam** » Wed Oct 05, 2005 9:21 pm

The non-LCV 'Minor' ratios were:

MM - 4.55 (41/9) standard or 5.286 (37/7) or 5.375 (43/8 ) optional
SII - 5.286 (37/7)
948 - 4.55 (41/9)
1098 - 4.22 (38/9)

The axle ratios changed when the 'series' changed for the cars.

Yes, a 4.55 gives better acceleration but a lower top end.
3.89 are available from MGs and are quite popular.

Taller tyres do affect the speedo rating. If your tyres measure 24" top to bottom, then when your speedo is showing 70 you will actually be doing 72.6 MPH

Morris Minor Owners Club

Incorrect Speedo

Incorrect Speedo

speedo

speedo

'Bible

diff

diff

diff

axle ratos