Diff ratio

[ca1066]

Hi all I have a1968 S2 FHC which I believe has European specs. The speedo in KPH has SN 6332/05 700 and the Rev. Counter RVI 4612/02 . I note from the knowledge base David Jones had a list of S1 ratio references but I can't find them for S2. I would be interested to know if I can ascertain the diff. ratio from the speedo reference above. Any comments appreciated. Thanks Paul.

[mgcjag]

Hi Paul.....anything could have been changed over the years.....you could count input turns to output turns to calculate.....originaly there was a small tag on one of the rear diff cover bolts with the ratio...worth looking for.. Steve

[chrisfell]

A quick way is to look at the diff itself. What you might see is something like this. (Echoing Steve's post)



This tab tells me that my diff has a 43 tooth crown wheel and a 14 tooth pinion wheel, making the final drive ratio 3.07.

[Hugo]

I would just jack the back end up & count wheel revs vs propshaft revs. That's the only foolproof method.

[Gfhug]

That's what Steve said above

[Hugo]

Yes, he said you COULD do that; I said it is the only foolproof method. Not quite the same thing

[ca1066]

Thanks for the comments and replies. I will look for the diff. tag , but was hoping that speedo reference SN 6332/05 700 would give me a clue . Regards Paul

[mark10337]

6332/05 is a km/h gauge calibrated for a 3.07 diff.

Speedometers are as follows
C.29165 Speedometer (Miles) SN.6332/01 -1312 OTS and FHC with 3.54:1 Rear Axle Ratio and S.P.Tyres
C.29543 Speedometer (Kilometers) SN.6332/02 -1216 OTS and FHC with 3.31:1 Rear Axle Ratio and S.P.Tyres
C.29544 Speedometer (Kilometers) SN.6332/03 -1312 OTS and FHC with 3.54:1 Rear Axle Ratio and S.P.Tyres
C.29545 Speedometer (Kilometers) SN.6332/04 -1060 OTS and FHC with 2.88:1 Rear Axle Ratio and S.P.Tyres
C.29546 Speedometer (Kilometers) SN.6332/05 -1120 OTS and FHC with 3.07:1 Rear Axle Ratio and S.P.Tyres
C.30913 Speedometer (Miles) SN.6332/06 -1216 OTS and FHC with 3.31:1 Rear Axle Ratio and S.P.Tyres
C.30914 Speedometer (Miles) SN.6332/07 -1060 OTS and FHC with 2.88:1 Rear Axle Ratio and S.P.Tyres
C.30915 Speedometer (Miles) SN.6332/08 -1120 OTS and FHC with 3.07:1 Rear Axle Ratio and S.P.Tyres

Rev Counter on a Series 2 should be a Smiths
RVI.4614/00 - Fitted up to Chassis Nos. 1R.1183 1R.9456 1R.20260 1R.26319 1R.35332 1R.42012
RVI.4614/01 - Fitted from Chassis Nos. 1R.1184 1R.9457 1R.20261 1R.26320 1R.35333 1R.42013 onwards

[ca1066]

Thanks Mark for that information . That's what I was hoping for . When the car is next on a hoist I will double check for that diff. tag . Regards Paul