diffs
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
By using this site, you agree to our rules. Please see: Terms of Use
-
- Newbie
- Posts: 2
- Joined: Mon Dec 08, 2008 11:30 am
- MMOC Member: No
diffs
Hi everyone , Sorry to ask what may be the obvious , but where do the 3.9 & 3.7 diffs come from ? MG Midgets ?? & if so does that mean the same PCD as a Marina ?
Thanks
John
Thanks
John
-
- Moderator
- Posts: 7679
- Joined: Fri Nov 01, 2002 2:55 pm
- Location: LEAMINGTON SPA
- MMOC Member: No
Midget is the likely source of a 3.9 and Wolseley 1500 (and maybe Riley) are likely source of the 3.7.
That's far from an exclusive list though!
That's far from an exclusive list though!
Ray. MMOC#47368. Forum moderator.
Jan 06: The Minor SII Africa adventure: http://www.minor-detour.com
Oct 06: back from Dresden with my Trabant 601 Kombi
Jan 07: back from a month thru North Africa (via Timbuktu) in a S3 Landy
June 07 - back from Zwickau Trabi Treffen
Aug 07 & Aug 08 - back from the Lands End to Orkney in 71 pickup
Sept 2010 - finally gave up breaking down in a SII Landy...
where to break down next?
2013... managed to seize my 1275 just by driving it round the block
Jan 06: The Minor SII Africa adventure: http://www.minor-detour.com
Oct 06: back from Dresden with my Trabant 601 Kombi
Jan 07: back from a month thru North Africa (via Timbuktu) in a S3 Landy
June 07 - back from Zwickau Trabi Treffen
Aug 07 & Aug 08 - back from the Lands End to Orkney in 71 pickup
Sept 2010 - finally gave up breaking down in a SII Landy...
where to break down next?
2013... managed to seize my 1275 just by driving it round the block
-
- Series MM Registrar
- Posts: 10183
- Joined: Sun Jul 24, 2005 11:39 pm
- Location: Reading
- MMOC Member: No
According to the Haynes Midget / Sprite manual, the 1275 Midget used a 3.9 diff and the 1500 Midget used the 3.9 and then the 3.7 diff. If the car was fitted with wire wheels then it would have had knock off hub nuts. As the diffs are removeable from the axle the PCD does not matter.
Diff ratios are stamped on the crownwheel.
Diff ratios are stamped on the crownwheel.
-
- Minor Legend
- Posts: 2147
- Joined: Mon May 10, 2004 9:10 pm
- Location: Oxford, UK
- MMOC Member: Yes
John,
3.9 diffs are fitted to the 1275 and early 1500 engined Midgets, and the 3.7 to the later 1500 Midgets and all Wolesley 1500 and Riley 1.5.
Not sure what you mean by PCD? The diffs are all the same fitting pattern, and can be fitted to any axle with a slight caution. None of the 3.9 or 3.7 diffs had the oil filler on the side (I think?), so will need to have the oil filler on the back of the axle, which the Minor did on later models, but not earlier. Fitting an earlier diff into a later axle gives you 2 fillers, but a later diff into an earlier axle gives no fillers!!
The wheel PCD's are all the same at 4" on all the axles, but the Midget axle is narrower, so is not suitable for a Minor.
Does that answer the question though?
3.9 diffs are fitted to the 1275 and early 1500 engined Midgets, and the 3.7 to the later 1500 Midgets and all Wolesley 1500 and Riley 1.5.
Not sure what you mean by PCD? The diffs are all the same fitting pattern, and can be fitted to any axle with a slight caution. None of the 3.9 or 3.7 diffs had the oil filler on the side (I think?), so will need to have the oil filler on the back of the axle, which the Minor did on later models, but not earlier. Fitting an earlier diff into a later axle gives you 2 fillers, but a later diff into an earlier axle gives no fillers!!
The wheel PCD's are all the same at 4" on all the axles, but the Midget axle is narrower, so is not suitable for a Minor.
Does that answer the question though?
Richard
-
- Minor Legend
- Posts: 1405
- Joined: Fri Sep 17, 2004 8:34 pm
- Location: Broughty Ferry
- MMOC Member: No
-
- Newbie
- Posts: 2
- Joined: Mon Dec 08, 2008 11:30 am
- MMOC Member: No
diffs
Thanks guys ... i know what to look for now ..
Yes - 3.7 diff from Wolseley or Riley - or later 1500 Midget. Just to add to the thread - ideally with a 3.7 diff fitted (and standard size 14 wheels/tyres) you need a speedometer with a 'tpm' of ~ 1236. There is a reasonably common Mini speedo with tpm of 1248 - I just bought one on ebay for £3 and so with this fitted the speedo will be possibly 3 % slow - but most read slightly high anyway - so I expect it be virtually correct.
tpm = turns per mile, and is noted on the speedo dial in small letters usually near the mileometer readout. For example - before I fitted my 3.7 diff, my car had a 4.55 diff - and a 1508 tpm speedo - and was ~ 1% fast on mileage.
The Mini speedo looks very similar to the Minor speedo - but does have one extra (green) warning light position at the top of the dial - may be useful for anyone fitting reversing light or rear fog warning light.
Edit -And this one on ebay appearsto be 1248 tpm - even better !
http://cgi.ebay.co.uk/austin-mini-speed ... 240%3A1318
tpm = turns per mile, and is noted on the speedo dial in small letters usually near the mileometer readout. For example - before I fitted my 3.7 diff, my car had a 4.55 diff - and a 1508 tpm speedo - and was ~ 1% fast on mileage.
The Mini speedo looks very similar to the Minor speedo - but does have one extra (green) warning light position at the top of the dial - may be useful for anyone fitting reversing light or rear fog warning light.
Edit -And this one on ebay appearsto be 1248 tpm - even better !
http://cgi.ebay.co.uk/austin-mini-speed ... 240%3A1318
Last edited by bmcecosse on Sat Feb 14, 2009 10:25 pm, edited 1 time in total.
I wondered if anyone could help me on the subject of diffs.
Having got the minor back on the road after 20 years of restoration, well alright 19 years in the pub and one year restoration I fitted 14'' alloys to it with 185/60r14 tyres as supplied by Bullmotif. The trouble is that its now all revs and no top end speed. The speedo is inacurate aswell but I can handle that. Does anyone know which diff would sort out the problem or would it be better to fit a 5 speed box ?
Having got the minor back on the road after 20 years of restoration, well alright 19 years in the pub and one year restoration I fitted 14'' alloys to it with 185/60r14 tyres as supplied by Bullmotif. The trouble is that its now all revs and no top end speed. The speedo is inacurate aswell but I can handle that. Does anyone know which diff would sort out the problem or would it be better to fit a 5 speed box ?
Can't see the tyres will be that much different to standard tyres - although 60 aspect ratio is a bit too low - 70 would have been much better. 5 speed box conversion is very expensive near 4 figures unless you can engineer/do it all yourself. Just get a 3.7 diff (~ £70) - it slots straight in -took me about 2 hours in total to swap mine. Then look for a 1248 tpm Mini speedo - mine cost ~ £3 from ebay, and fitted in about 1 hour. It works !
-
- Series MM Registrar
- Posts: 10183
- Joined: Sun Jul 24, 2005 11:39 pm
- Location: Reading
- MMOC Member: No
Depends how much money you have and how much work you want to do.
A 5 speed box will probably cost getting on for £1000 with all the bits and pieces although a 2nd hand one will be cheaper. There is probably a lot of work involved in fitting it. Can't be specific because I've never fitted one.
You can pick up a Midget diff for £50 -£150 and it will take less than 2 hours to fit including cups of tea.
A 5 speed box will probably cost getting on for £1000 with all the bits and pieces although a 2nd hand one will be cheaper. There is probably a lot of work involved in fitting it. Can't be specific because I've never fitted one.
You can pick up a Midget diff for £50 -£150 and it will take less than 2 hours to fit including cups of tea.
Last edited by mike.perry on Sun Feb 15, 2009 9:10 am, edited 1 time in total.
Here's a 3.7 diff on ebay! http://cgi.ebay.co.uk/MG-midget-Sprite- ... 240%3A1318
And - here's a 3.9 - they tend to be cheaper! http://cgi.ebay.co.uk/morris-minor-3-9- ... 240%3A1318
And - here's a 3.9 - they tend to be cheaper! http://cgi.ebay.co.uk/morris-minor-3-9- ... 240%3A1318