Ford 3.14 differential
Discussion
I've just been looking at the gear ratios on the Jaguar Getrag 221 box. 5th gear as we know is 1:1 ratio, so with the standard 3.64 diff I'd be pulling 3500 rpm at 70. Not the end of the world but if its driven daily that could get annoying.
I've seen that there was a 3.14 fitted to some of the older diesel sierras, select 1.6 OHVs and possibly some V6 Granadas.
As you can see from the before and after graphs, my eardrums would be eternally grateful.
I've seen that there was a 3.14 fitted to some of the older diesel sierras, select 1.6 OHVs and possibly some V6 Granadas.
As you can see from the before and after graphs, my eardrums would be eternally grateful.
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Ford Sierra Differential Ratios
RATIO VEHICLE SHAFT DIFF TEETH FINIS PART NO.
3.14 Sierra[TV28INJ](−Jan90) Lobro Non−LSD 1644899 85GG 4006 GB
3.14 Sierra[DL20](ABS),
Sierra[PD23](ABS)(−Jan90),
Granada[DL20](Feb92−) Lobro Non−LSD 6152100 87BG 4006 BA
3.14 Granada[DL20](Feb92−) Lobro LSD 6193181 88GG 4006 AEA
3.14 Sierra Lobro LSD 1648395 V87BG 4006 DAA
3.36 Sierra[TV29](Jan90−May91) Lobro LSD 6142222 85GG 4006 AAA
8500 4006 AAA
3.36 Sierra[LL23INJ](XR4)(USA/CDN),
Sierra[TV28](−Jan90),
Sierra[TV29](−May91) Lobro Non−LSD 6124451
3.36 Sierra[TV29](2WD)(May90−),
Granada[TV29](2WD)(Feb92−),
Granada[PD25T](Feb92−) Lobro LSD 6663905 91GG 4006 AAA
3.36 Sierra[TV29](May90−),
Granada[TV29](2WD)(Feb92−),
Granada[PD25T](Feb92−) Lobro Non−LSD 6663908 91GG 4006 FA
3.36 Granada[CP29] Lobro LSD 6831237 93GG 4006 AAA
3.36 Granada[VM25](Aug93−),
Scorpio[VM25](Oct94−Jan96) Lobro Non−LSD 6803399 94GG 4006 AA
3.36 Scorpio[VM25](Jan96−) Lobro LSD 1026116 96GG 4006 BDA
3.36 Scorpio[VM25](Jan96−Sep96) Lobro Non-LSD 1015630 96GG 4006 FA
3.36 Scorpio[VM25](Sep96−) Lobro Non-LSD 1035424 97GG 4006 AA
3.38 Sierra[HL18](Jan91−),
Sierra[D18T](Jan90−),
Sierra[TL16,TL18,TL20,TL20H,TV20,TV23,PD23] Tripod Non−LSD 6107625 83BG 4006 LC
3.38 Sierra[TL18,TL20,PD23]
Sierra[HL18](Aug89−), Lobro Non−LSD 1630004 85GG 4006 AC,
8500 4006 AC
3.38 Sierra[TL16,TL20,TV] Tripod LSD? 1619201 V83BG 4006 BA
3.38 Sierra Lobro LSD 1648394 V87BG 4006 CA
You could do a lot worse than talk to Bara at Bara Motor Sports. He is a known & reputable transmission guy, including Sierra diffs.
My S now has a 7" 3.14 lsd diff, to suit the AJ30 engine and its getrag 221 gbox. Some of those quoted above are 7"
Dont ask how mine feels, as its not quite up & running yet.
See terrys tale topic.
My S now has a 7" 3.14 lsd diff, to suit the AJ30 engine and its getrag 221 gbox. Some of those quoted above are 7"
Dont ask how mine feels, as its not quite up & running yet.
See terrys tale topic.
Edited by Blue 30 on Thursday 4th February 22:41
Is there a reason I can't use a 7" diff? As I understand they're essentially the same, just that I may need to insert a spacer and use a long bolt across the top. Will 7" Lobro bolt on shafts mate up to my existing drive shafts?
I'd imagine the 7" internals can be swapped into a 7.5" casing if shimmed correctly etc?
I've seen a 3.14 LSD for £500, and a 3.14 open diff for £250. Both 7"
I'd imagine the 7" internals can be swapped into a 7.5" casing if shimmed correctly etc?
I've seen a 3.14 LSD for £500, and a 3.14 open diff for £250. Both 7"
I wish I was an expert, but I'm not, so all I can quote is what I have done.
My 7" 3.14 LSD diff was purchased from eBay, it was advertised as a custom build for a customer who backed out of the deal, hence the Ad.
When I bolted it into the S little subframe, it required packing pieces to bolt it down securely. And when that assembly was fitted to the chassis, I measured diff flange to wheel flange each side.
It was sitting off centre !
So it needed about 10mm (I don't remember the exact figure) cutting off one bolt-through casting flange (easily done) to re centre it. Plus some packing on the other bolts. The shafts were now back with the correct length and float.
7" obviously refers to the crown wheel, so there's no great difference between 7" and 7.5".
Going back to mine being a custom build. I can only repeat what I was told... That there is no such thing as a factory built 7" 3.14 LSD 100mm flanged output diff.
But that conversion can be done, mine proves it.
Oh, you do need 100mm flanges on the diff, not the bigger Granada/Scorpio flanges.
And your current flanged diff shafts will not fit into an LSD diff, as the LSD diff shafts are of unequal length.
You're welcome to see mine in situ, in South Staffs.
As it's currently on my lift.
T
My 7" 3.14 LSD diff was purchased from eBay, it was advertised as a custom build for a customer who backed out of the deal, hence the Ad.
When I bolted it into the S little subframe, it required packing pieces to bolt it down securely. And when that assembly was fitted to the chassis, I measured diff flange to wheel flange each side.
It was sitting off centre !
So it needed about 10mm (I don't remember the exact figure) cutting off one bolt-through casting flange (easily done) to re centre it. Plus some packing on the other bolts. The shafts were now back with the correct length and float.
7" obviously refers to the crown wheel, so there's no great difference between 7" and 7.5".
Going back to mine being a custom build. I can only repeat what I was told... That there is no such thing as a factory built 7" 3.14 LSD 100mm flanged output diff.
But that conversion can be done, mine proves it.
Oh, you do need 100mm flanges on the diff, not the bigger Granada/Scorpio flanges.
And your current flanged diff shafts will not fit into an LSD diff, as the LSD diff shafts are of unequal length.
You're welcome to see mine in situ, in South Staffs.
As it's currently on my lift.
T
Edited by Blue 30 on Friday 5th February 11:11
Edited by Blue 30 on Friday 5th February 17:20
Edited by Blue 30 on Friday 5th February 17:21
Blue 30 said:
I wish I was an expert, but I'm not, so all I can quote is what I have done.
My 7" 3.14 LSD diff was purchased from eBay, it was advertised as a custom build for a customer who backed out of the deal, hence the Ad.
When I bolted it into the S little subframe, it required packing pieces to bolt it down securely. And when that assembly was fitted to the chassis, I measured diff flange to wheel flange each side.
It was sitting off centre !
So it needed about 10mm (I don't remember the exact figure) cutting off one bolt-through casting flange (easily done) to re centre it. Plus some packing on the other bolts. The shafts were now back with the correct length and float.
7" obviously refers to the crown wheel, so there's no great difference between 7" and 7.5".
Going back to mine being a custom build. I can only repeat what I was told... That there is no such thing as a factory built 7" 3.14 LSD flanged output diff.
But that conversion can be done, mine proves it.
Oh, you do need 100mm flanges on the diff, not the bigger Granada/Scorpio flanges.
And your current flanged output shafts will not fit onto an LSD diff, as the LSD o/p shafts are of unequal length.
You're welcome to see mine in situ, in South Staffs.
As it's currently on my lift.
T
Thanks for this info. Sounds like it's fairly easy to achieve.My 7" 3.14 LSD diff was purchased from eBay, it was advertised as a custom build for a customer who backed out of the deal, hence the Ad.
When I bolted it into the S little subframe, it required packing pieces to bolt it down securely. And when that assembly was fitted to the chassis, I measured diff flange to wheel flange each side.
It was sitting off centre !
So it needed about 10mm (I don't remember the exact figure) cutting off one bolt-through casting flange (easily done) to re centre it. Plus some packing on the other bolts. The shafts were now back with the correct length and float.
7" obviously refers to the crown wheel, so there's no great difference between 7" and 7.5".
Going back to mine being a custom build. I can only repeat what I was told... That there is no such thing as a factory built 7" 3.14 LSD flanged output diff.
But that conversion can be done, mine proves it.
Oh, you do need 100mm flanges on the diff, not the bigger Granada/Scorpio flanges.
And your current flanged output shafts will not fit onto an LSD diff, as the LSD o/p shafts are of unequal length.
You're welcome to see mine in situ, in South Staffs.
As it's currently on my lift.
T
Edited by Blue 30 on Friday 5th February 11:11
Looking at the tables online there were supposedly some 3.14 factory LSDs
3.14 Granada[DL20](Feb92?) Lobro LSD 6193181 88GG 4006 AEA
3.14 Sierra Lobro LSD 1648395 V87BG 4006 DAA
Are you saying that LSD diffs require different length drive shafts?
Edited by WhatamIgettingmyselfinto on Friday 5th February 13:30
No, not the o/p drive shafts.
As I refurbished my own, and refitted.
It's the short flanged shafts that engage into the diff itself that are of unequal length (on a LSD diff).
I don't know if your considering doing a diff refurb & reassembly yourself. But I have seen a detailed step by step process for that.... It doesn't look easy at all.
Here is a current eBay listing for a new 3.14 7" crown wheel & pinion.... Item 173392019256
It's not cheap !
T.
As I refurbished my own, and refitted.
It's the short flanged shafts that engage into the diff itself that are of unequal length (on a LSD diff).
I don't know if your considering doing a diff refurb & reassembly yourself. But I have seen a detailed step by step process for that.... It doesn't look easy at all.
Here is a current eBay listing for a new 3.14 7" crown wheel & pinion.... Item 173392019256
It's not cheap !
T.
Edited by Blue 30 on Friday 5th February 17:17
Jaye R said:
Hi
For those of us with little technical knowledge in this area
If i just wanted to do a straight swap for my current diff to a LSD what should i be looking for? Mine is a 2.9 S3.
Cheers
Jaye
Jaye - costs around £200 plus the LSD.For those of us with little technical knowledge in this area
If i just wanted to do a straight swap for my current diff to a LSD what should i be looking for? Mine is a 2.9 S3.
Cheers
Jaye
The LSD unit will fit into any 7 or 7.5 diff. I would budget 200 for fitting the LSD into your diff and setting up.
A ratio change, just add the cost of the cw+p.
Just remember the chances of over 120 mph is very rare and with the Getrag 221 Jag box that is 6000revs.
I have been told that the steering goes very light above that. Max revs with the Jag engine is over 7200.
LLantrisant said:
the easiest way to destroy any acceleration and liveness from your car is fitting a longer-diff.
the best anti-tuning activities for any car is fitting a longer diff.
a 3.14 ratio will not only cut your revs during cruising, it will also "destroy" your acceleration.
absolutely the best anti-tuning activities for any car is fitting a longer diff.
a 3.14 ratio will not only cut your revs during cruising, it will also "destroy" your acceleration.
Turns your S Series car into a Chim boulevard cruiser. 
But saying that I believe DamianS3 has a 3.14 and his car still manages 5.14 sec to 60 !!
Jaye R said:
I think I'll just leave things as non-LSD then
I thought the open diff let down the handling on my S2 - it could never make its mind up whether it was going to understeer or oversteer.The crappy viscous thing TVR used on the V8S was a little better but a friction plate diff really is the way to go if you spend time near the limit of grip.
LLantrisant said:
the easiest way to destroy any acceleration and liveness from your car is fitting a longer-diff.
the best anti-tuning activities for any car is fitting a longer diff.
a 3.14 ratio will not only cut your revs during cruising, it will also "destroy" your acceleration.
Normally yes, but in my case the Getrag gear ratios are much shorter, so even with a 3.14 diff I will have more acceleration in every gear. Would you want to drive around at motorway speeds in 4th gear in your car? Because that's what I'd be doing if I retained the standard diff.the best anti-tuning activities for any car is fitting a longer diff.
a 3.14 ratio will not only cut your revs during cruising, it will also "destroy" your acceleration.
WhatamIgettingmyselfinto said:
Normally yes, but in my case the Getrag gear ratios are much shorter, so even with a 3.14 diff I will have more acceleration in every gear. Would you want to drive around at motorway speeds in 4th gear in your car? Because that's what I'd be doing if I retained the standard diff.
and with an extra 100bhp I'd rather have a viscous LSD than an open diff.At the mo I have the Getrag 221 and the standard 3.65 viscous LSD but not done any more than 50 mile on a motorway
Edited by magpies on Sunday 7th February 21:31
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