Getting an LSD installed

[andy_harries]

Hi all

One of my thoughts for this winter was getting a limited slip diff installed in my 2016 Roadsport in the vain hope that it helps with my lack of talent on the track :)

My MOT is due in January and I had been planning to take the car to Caterham Gatwick to get it checked over, MOT and install the LSD they sell. However, reading the Titan thread on here has made me think that I'd be better off getting a Tracsport version installed instead.

Given the new lockdown means track days are off (just had an email cancelling a day at Silverstone next week ) as is blatting around the place, I was going to bring forward my plan.

Is it as simple as dropping out the diff (following the excellent information available on here !), emptying out the oil, boxing it up and sending it off to either SPC or Meteor Motorsport to get it fitted?  Or have I missed something? 

No idea what type of diff I have (BMW?), but its definitely an open one (wheels turn in opposite directions when turned when the back is jacked up).  Would they need to know, or can they just see when they've got it?

I'd take the whole car to Meteor Motorsport to get the Tracsport diff fitted, but I live in Watford so its a long old hike over there and the Welsh seem to be rebuilding Offa's Dyke to keep us plague infected English residents out 

[Tazio]

Grant Hibbet, Grant 7 on here had his diff removed and taken to Tracsport for his diff's lsd to be removed and their lsd installed. The work was done by Stuart Creswell at Premier Power.

 

[ScottR400D]

Yes, it is as simple as dropping out the diff etc and that’s really not too bad a job (I did it 3 times!!) though I’d suggest that you take the oil out first! 

Steve Perks is less than 2 hours from you so  you could take it to him but he’ll accept a carrier delivery. I had my new open BMW diff shipped to him from CC. 

Finally, a 2016 Roadsport should have a BMW diff (Black as opposed to alloy) and could well be open, no LSD, but could just have a non functioning Titan, though I suspect you'd hear the noise from that. 

That last thing I would recommend is having a Titan fitted. 

[nickh7]

I got a diff shipped for under £12 via Parcel Monkey and that's was Parcel Force .

[andy_harries]

Thanks chaps.  The diff is black, so I assume that its a BMW one. 

@ScottR400D - assume that I need to take the oil out first for two reasons - reduce the weight (I;ve read it's a heavy lump) and also otherwise it'll come pouring our when I remove the first driveshaft?

[Simon.Rogers]

Once the diff is out we can arrange DPD or FedEx to collect your boxed Diff for just £20 fully insured up to £10k

Be very very careful of the small print on the various online shipping brokers.  They even charge an additional insurance fee and in the small print you will find it states Car Parts Excluded.

Just a heads up.

 

 

[ScottR400D]

#5, Yes, it’s quite heavy. The oil doesn’t add too much to that but there more of a risk of spilling it once it’s out, so I always suck it out first. 

I don’t think it will necessarily leak when the shafts are removed. 

I used to have 1.2L in and it didn’t leak when I removed the shafts the first time. After that I refilled, as advised by RRT, with 0.8L. I can’t remember whether I removed the oil before the shafts after the first time but it obviously won’t leak at that level unless it tips over. 

Re the weight, I knocked up a very simple fixture from some old bits of wood which cable ties to my jack so that the diff sits solidly on it in just the right position to lower and refit. Makes it an easy 1 man job even for the inexperienced! 

 

[ScottR400D]

I said it was simple!!!

[Geoff Brown]

I created a similar removal/refit jig as ScottR400D.  The nose of the diff needs to be supported at the correct height not only to remove properly but to refit at the near as damn it correct angle to get it between the two lower support frame attachment bolts. My jig gave the diff a slight nose up attitude.

Beware it is a bit of a lump & nose heavy! 

I know this is a bit partisan but unless you want to relentlessly keep dropping the diff for a Titan refresh every year after being punished on track then get an SPC unit fitted as it will last much, much longer. 

[andy_harries]

@ScottR400D That looks genius.  Going to start rooting around in my garage for some scrap wood to make my own version!

@Simon.rogers - I will be in touch!

[Geoff Brown]

Bit late to the party after my reply but here is my Diff Jig.

Base is 220mm (l) x 240mm (w).  The ears are 205mm apart &125mm high (not including the thickness of the base) approximately 50mm from the rear. The nose block is 110mm (w) & 35mm (h) with 15mm thick high density foam on top. The central pad is again high density foam 65mm x 75mm, 15mm thick.

I found that having the ears gave stability especially when fitting the diff though you have to be reasonably accurate in positioning before raising. But you can jiggle the diff around a tad.

 

[andy_harries]

Thanks for the pic and the dimensions Geoff - the nose block looks quite a bit higher than the one Scott posted (if the number from the pic is correct, its 42mm high).  You mentioned that it does give it a nose up angle, but that would be quite a bit upwards with the BMW diff (I think mine is the same as in Scott's photo

'Ears' look like a cunning plan though!

[ScottR400D]

That puzzled me. Yes, 42mm high under the flat at the front and 25mm on the rear side flats. Basically supports the diff perfectly horizontally. 

I didn’t have an issue getting the nose by the bracket bolts which I slackened off to pull the bolts back out of the way (Tightened up the two threaded ends come in to a distance less than the drive flange so you have to lift the nose over them or pull them back out)

The final fit was with the carrier already on the diff so it went straight into place. 

[Geoff Brown]

AL 1 - I don't know why I stated the hight of the nose block as 55mm - I cannot read my own quick scribble!

The nose block height is 35mm + 15mm of high density foam on top. The foam allows the nose to settle at the correct attitude.

 

[andy_harries]

Ah, makes sense, thanks Geoff.

 

[700newtons]

Thanks for this very useful thread. 

[Geoff Brown]

You dropped the whole thing out. The diff will drop sans support frame. Saves re shimming then. Otherwise well done & I like the ears.

Should I copyright them?

[700newtons]

Yes, a useful design!

Are you telling me that I'm going to have trouble putting it back? I kept a record of where the shim washers go.

In retrospect another reason for leaving the cage behind is that there is less fiddling with the handbrake cable fixings - this caused me some hassle.

[ScottR400D]

It’s not that hard to refit with the cage already on. If you’ve kept a check on the washer positions as you say, the only issue is if they’re a tight fit, which they shouldn’t be anyway. 

The handbrake cable is a bit fiddly but in fact goes back really easily, IME, 

I was told by CC that they recommend the diff is removed c/w cage but they never gave me a clear reason why. Something to do with it flexing when the diff is taken out from it and it maybe not going back in exactly the same. 

I have no idea of the truth of that, though I doubt it’s too significant. I did notice that the long bolt, that had to be hammered in through the cage when originally fitted, was a quite loose fit through the cage once the diff was dropped out, which might indicate some movement. 

 

[Geoff Brown]

To drop the diff sans frame actually prevents any fiddling about with the hand brake cable. I cannot comment on the flexing as with the frame in the car I would have thought that it would be rigidly held. No the diff slips back in easily.

700newtons - I am sure that you will drop the diff out of the frame ?  You need to to clean & examine all surfaces with a bright light as there is a history of cracking. So check structure & welds inside & out.

[ScottR400D]

Andy's car is a 2016, Geoff, well past the time when the cages were suspect, though you do make s good point in any case about checking for cracks, that’s never a bad thing to do; a small point in favour of dropping the whole assembly maybe. 

 

[Rattie]

I had to drop the diff with the frame since it was an interference fit in the frame. No way would it have dropped out or gone back in without applying a significant spreading force on the sides of the frame. Since Geoff had no problem I'm guessing there's some batch variation.

I did find it useful to open the slot in the handbrake adjuster tab, then also warp that a little to pop the cable out. I then had to warp it back straight once the cable was back in.

The ATB works great by the way. I did it myself, but apparently Birds BMW will happily do the swap if needed.

[ScottR400D]

Bending out the handbrake cable bracket’s a fairly common thing, though for the few minutes taken to release the cable and unwind it from the bracket I preferred not to.

It’s interesting what you say about your cage, maybe that’s why CC advise leaving it on? 

 

 

[andy_harries]

I haven't actually taken my diff out as since the thread I caught the bloody virus as did the family so I've been recovering. Back to full strength now thankfully, but diff work will probably be after christmas now.

All the info in the thread is very useful and will be put to good use soon!

[Geoff Brown]

The frame must be jig built to a go/no go standard so the production tolerances will make the diff removal/ tight or loose by fractions. 

My diff just slid straight out & in. I noticed that there was barely 'fag paper' distance between the diff & frame but no witness marks in the areas one would expect which indicates a 'perfect' fit. 

Whomever built mine was having a really good day!