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        General >> How to do things! >> Diff Swap
        
(Message started by: Highlander on Jul 3rd, 2009, 11:44pm)
Title: Diff Swap
Post by Highlander on Jul 3rd, 2009, 11:44pm
Been meaning to do this for ages as quite a few people have shown an interest in doing it...

The Scorpio uses a 7.5 inch (crownwheel diameter) Differential

The diff transfers the drive from the propshaft to the rear wheels,  the diff "ratio"  is the number of complete revolutions the propshaft makes to turn the rear wheels once.

eg.

on the 2.0 16v the propshaft will turn 4.27 times to rotate the wheels one complete revolution.

on the diesel the prop will turn 3.36 times to rotate the wheels once.

The Scorpio diffs have different ratios for each specific engine type:

ENGINE  RATIO

2.0   8v   4.09
2.0 16v   4.27
2.3 16v   3.91
2.9 12v   3.64
2.9 24v   3.64
2.5 TD    3.36

http://www.fordscorpio.co.uk/manual/rearaxle/RAxleSpecs.pdf
(the spec for the 2.3 is wrong on the above link, they have a 3.91 ratio)

There are aftermarket diff ratios available (usually marketed for the 2WD Sierra Cosworth which uses the 7.5 inch diff but they are expensive!!)

http://www.kamdiffs.com/cosworth.htm

or you could fit a ratio from another make/model as long it has a compatible crownwheel and pinion, I've seen these range from 3.0 to 5.1



The reason for the different ratios is because of the power output of each specific engine, the lower BHP/Torque the lower the ratio on the diff.

The ratios are calculated for each specific engine size to give an optimum balance of performance (acceleration) and economy (engine revs at cruising speed)

I always try and explain it in terms of a pushbike..

If you start peddling in 1st gear its easy to get moving initially but before long you will be peddling flat out and not making much progress.. (fast acceleration, low top speed)

However if you start off in 5th gear you will find it really hard going to begin with but when you're eventually peddling flat out you will be doing a much higher top speed than your did in 1st gear (slower acceleration, higher top speed)

now transferring that thinking to our Scorpios...

the lower powered 2.0 starts off with its lower diff gearing to enable it to accelerate faster/easier while the larger V6's and the diesel with more BHP and torque can quite happily lay down enough power to move off fast under a higher gearing which allows them  top speed at lower revs.

Now the reason for changing the diff ratio..

I have done it for two different reasons.

Firstly I swapped the standard 3.64 diff on a 24v for the 4.27 diff from the 2.0 16v

What this did was allow the 24v to accelerate a lot faster (nearly two seconds off the 0-60 time)
The downside is that the engine sits 1000 RPM higher for the same speed so will use a lot more fuel at motorway cruising speeds compared to the stock diff.

Although this would reduce the potential top speed it would still hit the limiter at 140mph.

Secondly I fitted the 3.34 Diesel diff to a 2.3 replacing the 3.91 diff.

What this achieived was to reduce the acceleration but allow me to cruise at motorway speeds at lower RPM, losing performance for economy (I do nearly all motorway driving with this car).
Title: Re: Diff Swap
Post by Highlander on Jul 3rd, 2009, 11:45pm
The range of Scorpio diff's look almost identical from the outside, indeed the main diff bodies are identical, the difference is internally with the number of teeth on the crown wheel / pinion.

http://i44.tinypic.com/nfmbr5.jpg

There are two different types of backplate/diff mounting, both of which are interchangeable with each other, the older standard Ford mount on the left (picture above) and the newer double mount on the right (found on later model cars)

http://i40.tinypic.com/20uxqaq.jpg

The only other difference is the drive pinions (The round parts the driveshafts bolt onto)

The Diesel and 2.9's have 108mm diameter drive pinions (for bigger CV joints) the others have 100mm. again they are interchangeable as the internal shafts are the same size.
Driveshafts use internal T40 Torx bolts to bolt onto the pinions.

This is a diesel (3.36 ratio) on the left and a 2.0 16v (4.27 ratio) on the right (note the drive pinion sizes)

http://i43.tinypic.com/116usmx.jpg

The diffs are secured to the subframe by 19mm bolts (usually) one large bolt running right through the bottom centre of the diff/subframe, one either side towards the prop and one either side top rear.
There are 4 x 15mm prop bolts, these are arranged in a rectangular pattern, they are not equidistant so if its on wrong you cant line the holes up (been there got the T-Shirt) :)

http://i42.tinypic.com/2u9sqa9.jpg

The older single mount backplate is secured to the body by 4 x 13mm bolts

http://i43.tinypic.com/xbn52h.jpg

The newer style is bolted through the two mounts then
the subframe secured to the body by a single 15mm bolt


http://i41.tinypic.com/6iqk5j.jpg
Title: Re: Diff Swap
Post by Highlander on Jul 3rd, 2009, 11:46pm
The backplate is held on by internal T50 torx bolts.
when removing these soak them in in WD40 and scrape out the inside of the bolt head then hammer the bit in before trying to turn it, they are very soft and if the bit isnt in right they round very easily. (T-Shirt 2) ;)

Remember and point them front down before slackening the backplate or the oil runs out (T-Shirt 3) ;)

http://i40.tinypic.com/21oqzkp.jpg

A handy friend :)

http://i40.tinypic.com/wqtwm0.jpg

There is no gasket for the backplates, just a very smooth machined finish, I usually smear a light coating of oil on the faces before I reassemble them.

http://i41.tinypic.com/2likdv6.jpg

Its worth checking the condition of the oil fill plug at this stage and making sure it can be removed. (the diff on the left above had very little oil in it)

If you are changing the drive pinions over they are held on with circlips right on the inner edge of the shaft (circled on picture) be careful removing them, they can disappear into the depths of the diff (T-Shirt 4) ;)

http://i42.tinypic.com/v7tfsx.jpg

If you change the diff ratio the speedo will read incorrectly (lower ratio diff = higher speedo reading and vice versa)  it takes its reading from the Vehicle Speed Sensor (VSS) on the gearbox output shaft and the rear wheels will now be turning at a different rate compared to what they did with the old diff.

Automatic Gearbox VSS circled below

http://i41.tinypic.com/qxksc3.jpg

Or if its raining you can reach it by removing the gear selector :)

http://i31.tinypic.com/23k507.jpg

The VSS has a specific number of teeth to match it to the diff (21 teeth for 4.27 diff)  (19 for 3.91 etc)



The way around this is to fit the correct VSS drive pinion (bit with the teeth) for the new diff.

There are TWO different Autobox VSS that I know of (only found that out recently) and they are interchangeable.
The MT75 Manual gearbox has a different VSS.
It may be possible to interchange the drive pinions between the manual and auto VSS but I dont know, will investigate.

The clips that hold the different VSS types are different, and not interchangeable, you will need the correct clip.

These are the two Automatic VSS types, the left one is the most common, the right one seems to be the one Ford supply now as a replacent
I have found one of these on a Scorpio but it may not have been the original one

http://i43.tinypic.com/2le7bir.jpg

Note : The Scorpio speedo reads higher than actual speed (approximately 10%)
If you fit the VSS from the next lower ratio diff  the speedo will read almost exact speed.

eg

fit the 3.64 VSS from the 24v to the Auto Diesel

fit the 3.91 VSS from the 2.3 to the 24v

fit the 4.27 VSS from the 2.0 16v to the 2.3

Obviously you cannot do this for the 4.27 diff as there are no higher ratios

The following MT75 manual gearbox info may be of use

http://i40.tinypic.com/68ei2v.jpg
http://i39.tinypic.com/xdawqh.jpg

Not been able to track down similar info for the A4LDE box yet.

Changing the wheel size or more specifically the tyre size (diameter) will also affect acceleration and speed readings in a similar way to swapping the diff.

eg

smaller tyre diameter = faster acceleration and vice versa
but thats a whole other story   ;D

If I remember anything else or anyone else can think of anything let me know and I'll add it in ;)
Title: Re: Diff Swap
Post by martin_rowe on Jul 4th, 2009, 9:57am
Tooooo much spare time.

how about fitting the LSD diff from the MKIII 24v granada ?.
Title: Re: Diff Swap
Post by Highlander on Jul 4th, 2009, 10:09am
lol yes I do ;D  

would imagine the Granada LSD diff would be the same principle although only really of benefit to cars without traction control I would think
Title: Re: Diff Swap
Post by tlundkvi on Jul 5th, 2009, 10:30am

on 07/03/09 at 23:46:45, Highlander wrote:
These are the two Automatic VSS types, the left one is the most common, the right one seems to be the one Ford supply now as a replacent
I have found one of these on a Scorpio but it may not have been the original one

http://i43.tinypic.com/2le7bir.jpg


I had the one on the left in my 24V (manufactured nov. -94). I got the feeling the one on the right was the standard one and the one on the left the odd "Scorpio I" one. The one on the right I got as a replacement.

All service pictures in charts I've seen feature the one on the right. The clip for the VSS pinion seem different too. What do you think, is the driver pinion and it's clip interchangable as well, as I've as a precaution ordered a new pinion to eliminate wear factor of my VSS problem?


Thank you for the new guide, nice piece of work!
Title: Re: Diff Swap
Post by tlundkvi on Jul 5th, 2009, 1:07pm

on 07/03/09 at 23:46:45, Highlander wrote:
The VSS has a specific number of teeth to match it to the diff (21 teeth for 4.27 diff)  (19 for 3.91 etc)


I got to check this too, the guy at ford said 21 teeth for 24V. It was ordered based on VIN, so hopefully he read the info from the wrong place.

With logic:

(diff ratio / teeth) is approx. 0.2033 the V6 would have 18 teeth, the 8V would have 20, the diesel would have 16 or 17. Can anyone confirm this?

The pinion and clip was at FMD available for approx. 25 euros, suspect around £20 in UK inc. VAT.
Title: Re: Diff Swap
Post by Highlander on Jul 5th, 2009, 2:37pm
Interesting tlundkvi,

I seem to have found the opposite to you, all the VSS I have removed have looked like the one on the left apart from one.

Will have a look at a 24v VSS today and post the number of teeth, the diesel one might be harder to find as it would need to be an auto and i've never even seen one in the flesh :)

The MT75 VSS is different so we cant compare, however it does seem to follow the lower diff ratio = lower VSS teeth pattern.
I have posted new info on these above.
Title: Re: Diff Swap
Post by tlundkvi on Jul 5th, 2009, 4:30pm

on 07/05/09 at 14:37:38, Highlander wrote:
Interesting tlundkvi,

I seem to have found the opposite to you, all the VSS I have removed have looked like the one on the left apart from one.

Will have a look at a 24v VSS today and post the number of teeth, the diesel one might be harder to find as it would need to be an auto and i've never even seen one in the flesh :)

The MT75 VSS is different so we cant compare, however it does seem to follow the lower diff ratio = lower VSS teeth pattern.
I have posted new info on these above.


Or it was me that misinterpreted your reply om my post on the different VSS. I thought you referred to the metallic one when saying you never saw one of these before on a mk2 scorpio. I sourced a 2.9i Scorpio I from 1994 in Sweden that had the left style VSS. If you look at the guide I gave the link to in that very post, it is clearly the newer plastic frame model in the picture. Have seen plasic ones when browsing through bildelsbasen.se for mk2 scorpio parts. One is here: http://www.bildelsbasen.se/122-W533190.html

This post: http://www.fordscorpio.co.uk/cgi-bin/yabb/YaBB.pl?board=Advice;action=display;num=1245684243

But good that these kind of things get documented. The erratic behaviour  of my VSS is really interesting. It works when cold, but quits working when the  car gets hot after 6-8 minutes. If the car cools down for 1-2 hours the VSS works again for 6-8 minutes. Rarely, it will work again during the same run. If the pinion would be too worn, it would "jump" i'd say. It seems related to heat, but close to the VSS is only the front silencer, not the cat as I first thought. The rear heatshield foil is still in place. Maybe the plastic one is less sensitive to heat?
Title: Re: Diff Swap
Post by Tekno on Jul 6th, 2009, 10:57am
Does the (little bit different as stated above?) VSS from Granada III + A4LD still fit Scorpio ?
I'd like to put VSS from Granada III (3.64 diff) to my Scorp (3.91 diff) to correct speedo
Title: Re: Diff Swap
Post by tlundkvi on Jul 6th, 2009, 11:50am

on 07/06/09 at 10:57:12, Tekno wrote:
Does the (little bit different as stated above?) VSS from Granada III + A4LD still fit Scorpio ?
I'd like to put VSS from Granada III (3.64 diff) to my Scorp (3.91 diff) to correct speedo


Probably no difference, I'm not sure. But the pinion (the tip) can be ordered separately from Ford, you don't need to replace the whole VSS for that. Or just take the pinion from it if you already have it in your hands.

If you don't Tekno, I can detach the pinion from mine (3.64, 24V) and send it to you (mine is like the left one, I'm putting in a new like the one on the right). The VSS on mine is probably broken, but not the pinion. I can't reuse it when putting a new one in.
Title: Re: Diff Swap
Post by Tekno on Jul 6th, 2009, 12:40pm

on 07/06/09 at 11:50:48, tlundkvi wrote:
Probably no difference, I'm not sure. But the pinion (the tip) can be ordered separately from Ford, you don't need to replace the whole VSS for that. Or just take the pinion from it if you already have it in your hands.

If you don't Tekno, I can detach the pinion from mine (3.64, 24V) and send it to you (mine is like the left one, I'm putting in a new like the one on the right). The VSS on mine is probably broken, but not the pinion. I can't reuse it when putting a new one in.


pm sent.
Title: Re: Diff Swap
Post by Highlander on Jul 6th, 2009, 4:47pm

on 07/06/09 at 10:57:12, Tekno wrote:
Does the (little bit different as stated above?) VSS from Granada III + A4LD still fit Scorpio ?
I'd like to put VSS from Granada III (3.64 diff) to my Scorp (3.91 diff) to correct speedo


Tekno, you'll need a VSS from a 4.27 diff to show an accurate reading on a 2.3

If you fit the 3.64 one your speedo will read 20% higher than actual speed
Title: Re: Diff Swap
Post by Tekno on Jul 6th, 2009, 5:57pm
Humm... that's not what I want  ;D
Title: Re: Diff Swap
Post by tlundkvi on Jul 6th, 2009, 9:44pm
If you enter the in-dash diagnostics (press trip reset etc.) I believe the speed that is shown live digitally is much closer to the truth than the analogue one.
Title: Re: Diff Swap
Post by Highlander on Jul 6th, 2009, 10:44pm
I think they both use the VSS dont they?
They always seemed very similar when i've tried it
Title: Re: Diff Swap
Post by tlundkvi on Jul 7th, 2009, 9:03am

on 07/06/09 at 22:44:36, Highlander wrote:
I think they both use the VSS dont they?
They always seemed very similar when i've tried it


They do use the same VSS, but I think the error is induced slightly to the "needle". Not ofcourse saying the VSS is perfect, but I've used the diagnostics quite a lot when monitoring fuel levels (I have a 12.5 liter error at all levels). It has always shown a little less than the needle. Then again, the trip meter is pretty accurate which speaks for that the scorp knows the real value but shows something else. It uses the VSS signal too.
Title: Re: Diff Swap
Post by pinto on Jul 7th, 2009, 8:30pm
viscous LSD unit from the Granada III can be assembled inside the scorp case AFAIK - benefits would mainly be a REAL locking action over the traction control on the later models :)
Title: Re: Diff Swap
Post by Tekno on Jul 7th, 2009, 10:00pm
Would be nice traction in winter with LSD diff + traction control hitting also  ;)
Title: Re: Diff Swap
Post by Highlander on Jul 8th, 2009, 5:25pm
I'm guessing here but I think your traction control would cut in before your LSD would, making the LSD redundant when used with a TC system

I dont think they work as a combination do they?
I would have thought either one or the other with the TC being the better option of the two?

Anyone know for sure?
Title: Re: Diff Swap
Post by Highlander on Jul 8th, 2009, 5:44pm
Re tyres sizes

Standard 12 spoke tyre is 225/50/16

http://i9.ebayimg.com/02/i/000/b2/cc/1005_12.JPG

This is a 12 spoke fitted with a 205/45/16 which is on an XR4
3% reduction in circumference from the 225/50 which would give a slight increase in acceleration on the Scorpio and make the speedo read 3% higher (every little helps) ;)

http://i27.tinypic.com/ajv4wh.jpg
Title: Re: Diff Swap
Post by Tekno on Jul 8th, 2009, 6:10pm
I think much smaller tyres look a little funny because of bigger cap between them and wheel arches. Needs lowered suspension to not look so odd  ::)
Just my opinion   8)
In Sierra 205/45R16 look very good  :)
Title: Re: Diff Swap
Post by Highlander on Aug 5th, 2009, 8:26pm
I did weigh one once, under 30kg but not sure of exzct weight, 26 maybe
Title: Re: Diff Swap
Post by tlundkvi on Aug 14th, 2009, 8:06am
Regarding the VSS teeth. When I swapped VSS in mine, the tooth count was 21 on my 24V. I double-checked too, even marked the point where i started counting. My speedo has shown speeds a little more than the actual speed, but the internal speed as reported by the in-dash diagnostics was exactly the same as from a GPS. I strongly believe the pinion on mine is original.

Apparently as the number of teeth for 2.0 was also 21, 2.3 was 19, there must be something different, perhaps related to only the 24V used the A4LDE box. It would be interesting if this could be verified further. E.g. the 12V has a A4LD with the same diff ratio.

As is stated in the article text, the different VSS are fully interchangable. So are also the pinions, but only if accompanied with the corresponding retaining clip. So make sure you get a clip and pinion together if the styles are different.
Title: Re: Diff Swap
Post by Tekno on Aug 24th, 2009, 7:22am
Could someone list FINIS codes for VSS pinions please?
Title: Re: Diff Swap
Post by tlundkvi on Aug 24th, 2009, 7:59am

on 08/24/09 at 07:22:05, Tekno wrote:
Could someone list FINIS codes for VSS pinions please?


I never got mine from Ford, after two months waiting. Meantime the old one was installed without problem.

FWIW there seems to be only two for petrol auto versions, 19 & 21 teeth:

19 teeth (2.3 only): 6313349
21 teeth (2.0, my 2.9 24V had this): 6313353
Still don't know what 12V and TD uses.

Clip: 1631791 (verify this is of the same style, no other offered)

There are two designs of pinion and clip. Old clip+old pinion are together functionally equivalent with the new clip+new pinion, and can be installed on either the old or the new style VSS.

You'd get it much quicker if you accept a used one, unless somebody promises a date :) Cost around 25 euros.
Title: Re: Diff Swap
Post by Tons_of_fun on Aug 24th, 2009, 8:58am
Just to clarify  ::) ::) ::). The VSS on the 24v is the same as the 2.0ltr ? ?. Saves me a job then  ;D. Hopefully have a the diff on the cossie swapped soon  ;) ;).....Then im going looking for a certain VW Golf  ;D ;D ;D ::)
Title: Re: Diff Swap
Post by tlundkvi on Aug 24th, 2009, 9:09am

on 08/24/09 at 08:58:26, Tons_of_fun wrote:
Just to clarify  ::) ::) ::). The VSS on the 24v is the same as the 2.0ltr ? ?. Saves me a job then  ;D. Hopefully have a the diff on the cossie swapped soon  ;) ;).....Then im going looking for a certain VW Golf  ;D ;D ;D ::)


It appears so. Based on on diff ratios I would have expected 17 teeth, but my original (AFAIK) had 21 teeth, and there has been no counterexample posted either. Even FMD based on VIN suggested 21 teeth, but I was suspicious of this. My theory is the counterpiece in the gearbox the VSS takes readings from varies after all, but this may be A4LDE specific. We need somebody to check a 12V & TD to be sure the pinion will not have to be replaced to swap diffs.
Title: Re: Diff Swap
Post by Tekno on Aug 24th, 2009, 5:04pm
2.9 pinion (of VSS) is same as which 2.0 ? 8v or 16v ?
Title: Re: Diff Swap
Post by tlundkvi on Aug 24th, 2009, 5:23pm

on 08/24/09 at 17:04:25, Tekno wrote:
2.9 pinion (of VSS) is same as which 2.0 ? 8v or 16v ?


19 for 2.3 and 21 for others, check the posts above. Remember, the 24V A4LDE might have a different wheel/pinion *in the gearbox* than the A4LD on the others. If you swap your diff to a 4.27 you put a 21 teeth pinion in, if you put a 3.64 I would leave the 19 teeth one in, and hope the error will not change.

BUT the Granada mk3 facelift with 3.64 or 3.62 diff used an 18 teeth pinion with A4LD. This would I be looking for. Finis 3512264 & ring 1635335. Strangely, ths does not show up for Scorpio II.
Title: Re: Diff Swap
Post by Tekno on Aug 24th, 2009, 6:43pm
Humm. Could be worth checking which kind of pinion does my old and rus.. trusty Granada III have..

should more teeth increase speedo's value or vice versa?

Title: Re: Diff Swap
Post by tlundkvi on Aug 24th, 2009, 8:06pm

on 08/24/09 at 18:43:26, Tekno wrote:
should more teeth increase speedo's value or vice versa?


Less teeth -> more revolutions per second -> higher speed is shown

Bet you have something like the metal VSS in your old one. Atleast you will be able to steal the pinion+clip from it.
Title: Re: Diff Swap
Post by Highlander on Aug 24th, 2009, 10:09pm

on 08/14/09 at 08:06:39, tlundkvi wrote:
Apparently as the number of teeth for 2.0 was also 21, 2.3 was 19, there must be something different, perhaps related to only the 24V used the A4LDE box.



on 08/24/09 at 08:58:26, Tons_of_fun wrote:
Just to clarify  ::) ::) ::). The VSS on the 24v is the same as the 2.0ltr ? ?. Saves me a job then  ;D. Hopefully have a the diff on the cossie swapped soon  ;) ;).....Then im going looking for a certain VW Golf  ;D ;D ;D ::)



Guys we're getting confused here....

All the Scorpios used the A4LDE box not just the 24v apart from the 12v and the diesel.
Title: Re: Diff Swap
Post by Tekno on Aug 25th, 2009, 12:33pm
http://img523.imageshack.us/img523/7163/dsc04883c.th.jpg (http://img523.imageshack.us/i/dsc04883c.jpg/)

How do I detach that VSS ???
Gearbox is A4LD

It's not even possible, do you think same?
Title: Re: Diff Swap
Post by Highlander on Aug 25th, 2009, 1:09pm
Looks like the clip is missing, is it glued in??  ;D
Title: Re: Diff Swap
Post by Tekno on Aug 25th, 2009, 1:11pm
I removed metallic clip before taking photo. But that clip was just for holding the connector?  ???
Title: Re: Diff Swap
Post by tlundkvi on Aug 25th, 2009, 1:19pm

on 08/25/09 at 13:11:15, Tekno wrote:
I removed metallic clip before taking photo. But that clip was just for holding the connector?  ???


There's a screwhole right where a part has snapped off (check the picture of the sensor in the first posts).

I think you should be able to prise it out very easily (unless glued there).
Title: Re: Diff Swap
Post by Highlander on Aug 25th, 2009, 1:57pm

on 08/25/09 at 13:11:15, Tekno wrote:
I removed metallic clip before taking photo. But that clip was just for holding the connector?  ???


The clip also holds the sensor in position,it  SHOULD as the they say in the Haynes manual just fall out :)
Title: Re: Diff Swap
Post by Tekno on Aug 25th, 2009, 2:11pm
correction:

PHEW, finally it detached.. d*mn it was tight :D

I found there is 20-teeth pinion.

If I want speedo reading to _decrease_, should I put that pinion to newer scorp (2.3) ?
Title: Re: Diff Swap
Post by tlundkvi on Aug 25th, 2009, 2:56pm
If your old one is a 19 teeth, yes. Sure you don't need you old scorp?
Title: Re: Diff Swap
Post by Tekno on Aug 25th, 2009, 4:05pm
Strange that it (2.0 8V mkIII) has different pinion.. as it has same rear diff ratio as 2.3 frog eye
They wanted to make speedo have more false reading than older model  }{
Title: Re: Diff Swap
Post by Tekno on Aug 26th, 2009, 1:52pm
Finally done VSS swap ;D

Before: Error was 11%
After: Error is 5%

I'm very happy now :)
BUT, if anyone has spare 21-teeth pinion, would be PERFECT to let me know 8)

Earth wire was VERY VERY corroded and it snapped just because I did touch it. Replaced it with new one.
Title: Re: Diff Swap
Post by Tekno on Sep 5th, 2009, 8:42am

on 08/24/09 at 22:09:58, Highlander wrote:
Guys we're getting confused here....

All the Scorpios used the A4LDE box not just the 24v apart from the 12v and the diesel.

The 2.0 16v and the 24v VSS ARE different.. if you put a 4.27 diff in your 24v the speedo will read WAY over, around 20mph! (i've tried it) :)

I dont have the 24v teeth number, will find it out this weekend though.


Did you find it out?
Title: Re: Diff Swap
Post by Highlander on Sep 5th, 2009, 10:30am
lol no!


I'm just wondering if theres some difference in the actual instrument clusters which would interpret the signal in a different way??

I know if you put a 16v instrument cluster in a 24v the RPM reads about 50% above what it should, i wonder if the speedo is the same..
Title: Re: Diff Swap
Post by Tekno on Sep 24th, 2009, 2:52pm
How do you remove the circlip on the tip of drive pinion?
Title: Re: Diff Swap
Post by tlundkvi on Sep 24th, 2009, 3:36pm

on 09/24/09 at 14:52:40, Tekno wrote:
How do you remove the circlip on the tip of drive pinion?


You just push it a bit with a small flat screwdriver. It can be a bit tight but it should not snap.
Title: Re: Diff Swap
Post by Tekno on Sep 24th, 2009, 4:49pm
1 circlip broken already... 5 left..  }{
screwdriver+hammer wasn't good idea.
Title: Re: Diff Swap
Post by tlundkvi on Sep 24th, 2009, 5:52pm
That's a shame, mine came off really easily, I just bent and pushed it a bit from the side and it slipped off. Then again it was soaked in ATF when I did it. The newer style clip slides from the top (it looks like, never saw one), seems better :)

But you said you had 5...
Title: Re: Diff Swap
Post by Highlander on Oct 2nd, 2009, 9:00pm
Hi Guys,

Have worked out a NEW speedo correction method, no need to change the VSS!!  ;D

1) Find out how much your speedo is out using satnav.

The one i did this with showed 70mph (speedo reading)   and (52mph actual speed showing on satnav) so it was reading 18mph fast.

2) A rolling road or MOT station would be advised for this next bit..

Being a bit rough and ready i just jacked the rear wheels of the car up on two axle stands but BE CAREFUL if you do this..

I had it facing a wall and had the rear axle chained down just in case!

Dont do it with the car pointing downhill towards the local school!!

Remove the dash,

unscrew the clear cover off the instrument cluster
Start the car,
put it in gear,
get the speedo showing 70mph (cruise control is ideal if you have it)

Now the magic bit..... ;D


Pop the speedo needle off and replace it pointing at 52mph!

WHY didnt I think of that before!!

Works a treat! ;D
Title: Re: Diff Swap
Post by gozz on Oct 2nd, 2009, 9:42pm
Stuart.
You didn't think of it before because it's too simple in the modern technological world  ;D
         GOZZ.
Title: Re: Diff Swap
Post by tlundkvi on Oct 2nd, 2009, 9:52pm
Oh, and I was thinking a resistor between the voltage supply to the needle would do the trick...

Really, internally the scorpio knows it's speed.
Title: Re: Diff Swap
Post by Tekno on Oct 2nd, 2009, 11:12pm
that needle trick is good, but not perfect (It corrects speedos static error). Usually speedo has (also/only) error which increases linearly (speedo shows always same _percentage_ above actual speed...). You may get speedo showing correct in, for example 60mph, but then it shows too low at 0-40.. and still too much in 80+mph.
Title: Re: Diff Swap
Post by Highlander on Oct 2nd, 2009, 11:26pm
True BUT...

I used an actual speed of 52mph so it will read 52 and not  57ish as it normally would be with a standard unaltered speedo.

(80 mph actual speed now shows 82 on the speedo)

So although i agree its not perfect its only going to be a couple of mph out (unless you hit 140) which is a lot better than the standard set up.

I reckon an actual speed of 140 would show 149 on the speedo now

Title: Re: Diff Swap
Post by Tompion on Oct 3rd, 2009, 8:54pm
I suspect a dash reset teaches the instruments where the zero stop is, in which case the next time you disconnect the battery or the needles flick round it may return to the previous setting.
Title: Re: Diff Swap
Post by gozz on Oct 3rd, 2009, 8:59pm
Tompion.
Are we not looking at a mechanical intervention here,as against an electronic one ?
                                                  GOZZ.
Title: Re: Diff Swap
Post by Tompion on Oct 3rd, 2009, 9:26pm
Gozz
In a way that’s the point.
Moving the hand on a Chronometric or rotating magnet type would alter the reading albeit still as inaccurate over the full range of the dial but that won’t necessarily be so for an electro-mechanical device.

You may be right, I’m just guessing – based on the way I know the rotor work.
It’s certainly possible for them to behave the way I mentioned, but I haven’t tested whether they do (something I was going to check out if I ever get round to looking for the airbag problem in my dash).

Dave
Title: Re: Diff Swap
Post by Tekno on Oct 22nd, 2009, 12:48pm
Do you know where to get spare sirclips for drive pinions?

what is exact size??
Title: Re: Diff Swap
Post by tlundkvi on Oct 22nd, 2009, 1:22pm
Ford lists them as available for around 1 euro. You need to order for mk3-facelift granny to be sure you get one of the right style (metal VSS version). Otherwise you must change the pinion too. I can go via my local FMD to see if the backordered clip ever came and to see if it looks correct. A 21-teeth pinion was also ordered the same time. I won't need either anymore.
Title: Re: Diff Swap
Post by Tekno on Dec 21st, 2009, 9:48pm
Took 7 hours to detach diff!  ;D
Patience and lengthy torsion bars are needed.
Title: Re: Diff Swap
Post by gozz on Dec 21st, 2009, 10:13pm

on 10/22/09 at 13:22:09, tlundkvi wrote:
Ford lists them as available for around 1 euro. You need to order for mk3-facelift granny to be sure you get one of the right style (metal VSS version). Otherwise you must change the pinion too. I can go via my local FMD to see if the backordered clip ever came and to see if it looks correct. A 21-teeth pinion was also ordered the same time. I won't need either anymore.

I think he may mean circlips for the output shafts ?
                          GOZZ.
Title: Re: Diff Swap
Post by gozz on Dec 21st, 2009, 10:19pm

on 12/21/09 at 21:48:36, Tekno wrote:
Took 7 hours to detach diff!  ;D
Patience and lengthy torsion bars are needed.

I have found that the force of gravity plays a very important part of diff removal  ;D
                                  GOZZ.
Title: Re: Diff Swap
Post by Tekno on Dec 22nd, 2009, 10:19am
Reinstalling everything was just 4 hours
Title: Re: Diff Swap
Post by wumpster on Dec 22nd, 2009, 7:39pm
what sort of differance would it make puttin a 24v diff in a td as my td diff is on its way out and will the 12v or 24v match up to every thing on the td or will a mk3 diff out of a td go in ok answers on a post card please lol   ::)
Title: Re: Diff Swap
Post by gozz on Dec 22nd, 2009, 9:08pm
Wumps.
Being lower geared the V6 diffs would give you a little less MPG,as far as I know the diesels and V6s all have the big output flanges,if the rear cover has a different mounting arrangement you can swop em.Not sure about Mk 3s.
                                                   GOZZ.
Title: Re: Diff Swap
Post by Tekno on Dec 22nd, 2009, 10:20pm
mk3 will fit too, but has old style backplate (without bushes)
Title: Re: Diff Swap
Post by wumpster on Dec 23rd, 2009, 6:19pm
ok ta folke gives me some opptions as i might be able to get me hands on a mk3 drev diff cheap  ;) if not 2.9 one will go in any ide how much diff it makes to rpm or speedo
Title: Re: Diff Swap
Post by Tons_of_fun on Dec 23rd, 2009, 7:37pm
Trev, i have a cossie diff if you need one m8  ;)
Title: Re: Diff Swap
Post by gozz on Dec 23rd, 2009, 8:19pm
Wumps.
The diesel and V6 diffs are only .28 apart,this difference is not great,so if you left the VSS pinion in it would show a little higher speed than you were actually doing.
                                                 GOZZ.
Title: Re: Diff Swap
Post by wumpster on Dec 25th, 2009, 1:44am
cheers all for the advice might take you up on the cozzy diff m8 let me knowe how much m8  ;)
Title: Re: Diff Swap
Post by Tekno on Jan 6th, 2010, 8:24am
Before (3.91) : 80-120 8.1 seconds
After (4.27): 80-120 6.5 seconds

I wonder what Cossie would get with this gear ratio + and manual gearbox :)
Title: Re: Diff Swap
Post by tve on Jan 12th, 2010, 2:36pm
Established differential of the raised friction?


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