BMW/Titan LSD Viability

[O.G.]

Geoff,

I think you have your answer about is there an iceberg of failures and concern.

In 72 hours of your initial post you got 74 comments from 19 different members, nearly all expressing deep concern. Add to that nearly 2000 Views!

I feel I was sold a LSD pup. New to Caterham ownership in 2015 when I ordered my kit, stating it was for spirited road use with a few track days in mind I was advised that a LSD would be preferable. At no time was any mention made of any noises, clunking or the extreme extra maintenance required. 

Some people have said that with LSDs these sort of failures come with the territory. I don't accept that, this is a light weight car with a Diff for cars with probably more power and more than twice the weight. I feel the problem lies with the modifications carried out by CC to adapt it to our otherwise brilliant cars. 

Where is it in the service schedule to carry out frequent checks of the Diff. function. There is not even in my hand book a mention of changing the oil and to add insult to injury your not even provided with a drain plug!

I know these are specialist quirky cars and have to be maintained using a different philosophy to conventional cars but something lurking deep in the workings that needs extensive checking and rework and could fail with expensive consequences is not what anybody wants or expects.

Is there a part for The Club to play in this regarding CC?

O.G.

[7 wonders of the world]

OG,

CC havent adapted the LSD for the car they have simply specified a poorly designed unit from an outside supplier - Titan.

At the time CC started to use the BMW final drive (due to the Ford unit no longer being available in the numbers required) there were limited options with regards to LSD for these units.

This does in no way detract from the fact that many owners are suffering from high wear rates on the plates and premature failure of the belleville springs - both design issues.

It's fair to make comaprison with tin tops running similat plat LSD's which, despite running much higher preloads do last well into 6 digit mileages without any form of maintainance apart from scheduled oil changes.

The point regarding race cars not seeing the same level of failure has a degree of merit as road cars will see more differential operation and therefore suffer more slippage on the plates, however even with low preloads plate wear is still excessive hence the preload failing away.

The root cause is the design of the Titan LSD not the BMW final drive unit.

[ScottR400D]

OG. I bought my car in 2015. Good friends who I’ve made through the club also bought their cars around that time, a little earlier or a little later. 

Most have the LSD fitted and none of us was aware of the ‘fragile’ (let’s say) nature of it. One of the group built his 420 last year and he was also totally unaware of any regular maintenance needs. 

To be fair, the guys with 270/310 cars or equivalent haven’t had any issues yet, it seems it’s once you get the significantly greater torque of the Duratec, especially with more than 200bhp, that the LSD’s life is limited, to say the least.

Then again, the guys with the lower powered cars don’t, or haven’t as far as I’m aware, been checking preload; for all I know the LSDs may be non functioning by now.

In hindsight I now know that my LSD wasn’t functioning for a while but I didn’t recognise the signals from the loose rear end (!) until it was too late. Maybe they’re not so clear with 70/90 less horsepower and correspondingly lower torque and a non functioning diff can be missed in normal road driving.

As for the club taking it up with CC, I don’t know how that would work. My experience is one of a lack of concern from the manufacturer, justified by what I believe to be retro introduced maintenance recommendations which they fall back on.

I now believe CC are, and have been, well aware of the shortcomings and have been trying to rectify them by changing the friction plates and oil recommendations. Those proving pretty ineffective they’ve fallen back on “Well, yes, of course they need regular maintenance and rebuilds”.

Just my feeling, no definite evidence.  

 

 

[Nigel B]

I drove Caterham’s 420R demonstrator at Crawley last year, before buying my car & it had the most horrific sounding diff I’ve ever experienced. I mentioned it to the sales guy (before we’d even left the car park) & he laughed it off, saying it was also Caterham’s press car & therefore got a lot of abuse, doing 0-60 runs. 

The 420R I bought, sounded much better by comparison, for a while at least! Perhaps it’s Caterham’s sales technique, take the customers out in a duff one first?

[Wrightpayne]

My mate had a mk1 escort in the 80s with a plate LSD - it clonked, grated and banged when manoeuvring slowly but once on the move was quiet. A bit of noise comes with the territory of an LSD, more so in a seven because the diff is fairly rigidly mounted 18 inches away from your left ear!

A bit of noise is normal.

Ian

[7 wonders of the world]

Not the case Ian,

Yes you are unduboutably closer to both the transmission and final drive, we have much less noise insulation and firmer mounts so NVH will never meet the levels of a modern tin top.

The problem here is a fundamental failing due to premature wear which can be attributed to poor design.

Many Escort LSD's were built tight (70-80lbs/ft preload) for gravel use so their on road manners were cherpy are normal cornering speeds.

My ZF - which owes it design to the same era is silent in operation......

TADTS is not an acceptable response

[Wrightpayne]

Neil,

I was not suggesting for a moment that the noise experienced by some owners was either normal or acceptable.

There are many new members here, new to seven ownership so was trying to inject a bit of balance in that certain differentials, open or otherwise, will be noisy compared to their tintop. Not everyone has a car perfectly engineered like yours and LSDs do chunter and can perform perfectly for a very long time without issue.

The pre-load test seems the definitive way to see if there is an issue.

Has anyone researched longevity / issues with Titan diffs in other applications? 
 

Ian

[Geoff Brown]

I am really glad that I resurrected this subject! O.G. #76 has quoted the number of comments & views. Some of the views I would suggest originate from Dartford or Croydon........?

Although ScottR400D raised the spectre of the Titan LS unit (many thanks) what was required is this informed discussion which has exposed the iceberg & alerted many other owners to the pit falls of the Titan caused to some extent by poor design. Hopefully for warned is for armed.

There has been some discussion about the 100% compression of the washers in the Titan this I believe is because there is nothing to restrain them. I had a good look at the SPC LS unit where the washers sit in a recess so when they are compressed there is a set limit as to how far they can go. 

As far as in service preventative maintenance is concerned I am considering up loading this simple guide to the web site. So I require a peer review to ensure that it is correct as far as possible. Please post comment, additions or required amendments.   

 

BMW/TITAN LSD - In use checks/maintenance

Titan recommend that the LS unit installed in the Seven BMW differential requires to be removed & serviced every 10,000 miles of road use & annually for a race car. If the road miles also include several track days per year then the period between servicing may well reduce.

https://titanexpress.co.uk/collections/drivetrain/products/lsd-rebuild-kit?variant=32355122053202 

To monitor the in service health of the Titan LS unit & hopefully extract the maximum in service mileage/calendar period the following actions are recommended:

1) Diff oil. Use a good quality SAE 90 GL5  LS oil. 

2) Annual oil change. Any distinct change to the colour of the removed oil should be investigated.

3) Magnetic filler plug.  Fit to monitor the LS unit health. https://www.ebay.co.uk/itm/283500049956 

3) Wheel rotation logic check. With the rear of the car raised rotate one wheel. The other should turn in the same direction. Non rotation of a wheel or in the opposite direction indicates possible internal failure of the LS unit. 

5) LS unit pre load break away check. Remove one wheel & carefully balance the vehicle on the remaining three corners ensuring adequate support & chocks in place. Using a torque wrench applied to the hub nut adjust the wrench until the axle breaks away. A digital wrench is recommended.

40ft/lbs = satisfactory.  20ft/lbs = consider a rebuild.  15ft/lbs = failure could be imminent.

It would be appreciated that someone who has DIY experience of dismantling, servicing & setting up the BMW/Titan combo to do the same?

 

https://titanexpress.co.uk/collections/drivetrain/products/lsd-rebuild-kit?variant=32355122053202 

 

[ScottR400D]

I might have agreed till I got the SPC LSD installed. It’s a similar design but it makes no  clunking or grinding noise. Nothing at all. 

At first I thought there was noise on the overrun but discovered that’s the box, it’s different in different gears. There is a CWP chatter on light lift off but that’s easily avoided.  

Without earplugs you hear normal transmission noise, just as with the gearbox but nothing at all that you wouldn’t get from say an open diff.  

If I get a break in the weather before the end of the month, I’ll make a recording and make it available alongside the one I did of the sintered plates Titan.  

[ScottR400D]

Comments on Geoff’s proposal:

10k may be too long, especially in higher powered cars, though the checking regime should indicate a rebuild when needed if you don’t get to 10k.

CC now recommend a 75/140 grade of oil RRT and SPC a 90 grade. CC used to recommend 90, but changed for some reason.  

To torque check I would put the car securely on axle stands, leave a wheel on one side, stop that wheel turning by putting a length of wood through the spokes and bringing up to the calliper or some other solid part. (I know it sounds crude but there are several places where it can be safely wedged) then apply a wrench to the other side, starting around 20 ft lbs and gradually building up until the wheel turns. If it turns at 20 then check for a lower figure but, to be honest, if it’s 20 you likely need a rebuild anyway.  

[Petethediesel]

A very good post.

   My 180 hp Duratec with the BMW/Sintered plate LSD,has now done 5,000 miles road use. The torque is around 30 ft lbs so OK for now. The LSD noise was significantly reduced by switching to RR's GL5 90 grade LSD oil. Following very helpful discussions with ScottR400, I will switch to the Tracsport when the time arrives. 

  With 20/20 hindsight I would have been better to order my kit with a open diff and have the Tracsport fitted during the build, It works out around £200 more than the CC LSD option, but longevity is important to me. I would certainly recommend this route to anyone shaping  their kit spec.

[Mrp]

I have a 3000 mile 420R what diff should I source for exchange if I swap to a SPC diff which I would get Nick Potter to swap. Mrp

 

[Alan Bowler]

2011 Titan LSD in Ford casing. Couple of oil changes. Road and Track. 140bhp. Not too noisy, no issues. About 20k miles. 

[ScottR400D]

Mrp, I'd recommend you just have the Titan LSD swapped for the SPC in the same BMW housing and with the existing CWP. Have Nick Potter remove and replace the full unit but let Steve Perks swap the internals.

[R400svn]

Hi all, having just read all these posts and picking my car (420r) up from Silverstone Caterham in the wet  after its mot and noticing wheel spin from only the one wheel I have done the wheel turn test and described above and on turning one wheel the second is stationary and sounds like I have the same problem as many here. Question if I continue to use the car until I get it back to the dealer am I causing more damage and expense or is it just working as an open diff. If they dealer won't sort it is the diff easy enough to remove and I will look of change to the spc diff.

Great topic and hugely helpful 

[R400svn]

Hi all, having just read all these posts and picking my car (420r) up from Silverstone Caterham in the wet  after its mot and noticing wheel spin from only the one wheel I have done the wheel turn test and described above and on turning one wheel the second is stationary and sounds like I have the same problem as many here. Question if I continue to use the car until I get it back to the dealer am I causing more damage and expense or is it just working as an open diff. If they dealer won't sort it is the diff easy enough to remove and I will look of change to the spc diff.

Great topic and hugely helpful 

[ScottR400D]

R400svn. It goes without saying that if you can turn one wheel easily and the other didn’t turn, you have no significant preload.

That implies the LSD is worn and needing overhaul or replacement. 

I think the biggest risk to other parts of the whole diff is if Bellevilles break up. That may or may not happen if you drive it carefully. I guess the question is “Do you feel lucky?”  

Well, do you?........

As for removing and replacing the diff, those of us who’ve done it would likely say it’s not too hard. It’s not technically difficult but there are a few wrinkles to know about. 

During my diff related epiphany I removed and replaced my diff three times in a month or so. I also helped (I hope) coach Nigel B by e mail and he managed his easily enough. 

I certainly think anyone with basic availability and the right tools could do the job and I’m sure there are plenty on here to advise and even help physically if necessary, including me. 

How many miles has your car done by the way? 

[Mrp]

#89 Thanks Scott just for info what is the SPC turn-a-round (if you know), as Nicks space is a bit limited hence the original question. and for me to plan when I should do this. I will do your test but by the sound of things I will have to do it at some point shortly. I should add mine has the Throttle body upgrade so more torque and 220 bhp, so 440 R !

Having done the switch to an LSD on my original 140 (2009) with a Ford diff done by seven and classics I was not really expecting this in my budget. 

Mrp

[David Brown]

After speaking to Road & Race about clunking when manuevering with the Titan they had just installed, they said I should add a small tube of friction modifier to the oil.  Whether it improved the life of the lsd I can't comment as sold the car but it did cure the low speed noise. 

[7 wonders of the world]

The friction modifier wont improve the life off the plates it merely reduces the friction an allows the plates to slide rather than chatter thus reducing noise at slow speed manovures.

[BobM]

As a newbie currently contemplating ordering a 420R in kit form this thread has been equally fascinating and worrying!

If a DIY refurb of the LSD every year or two at a cost of £350 or so is called for I can live with that. I'm a reasonably competent DIY mechanic (I've built 4 kitcars before, rebuilt engines and maintained my own race car) but have never worked on diffs and can't find any howto's or guides online. Such a document would be an invaluable addition to the technical guides section on here. A video guide would be a useful supplement.

I guess the alternative is to try to order the kit with an open diff and fit a different LSD which I gather from this thread will work out more expensive. My last car had a Quaife ATB (mid-engined, bike engine, chain dirven), the one before that a Sierra diff with viscous LSD.

It would be helpful if some of the experienced contributors to this thread could indicate what they would do if they were speccing a new car.

[Wrightpayne]

Bob,

I'd order without the LSD and take the rebate. You can then choose where to spend your money. This used to be quite a common pathway many years ago where customers would source their own engines etc 

I've had the sierra diff out of mine a few times (and helped others on a few), while it is not too difficult I wouldn't want to be doing it every couple of years as a 'service' item.

Regards

Ian

[ScottR400D]

Knowing what I know now I would definitely spec an open diff and get an SPC LSD fitted before I built the car. By my calculation that would be £3/400 extra cost, which would be quickly recouped. 

I think the LSD is standard in the 420R though and CC might be reluctant to supply without  in that case I’d ask them for a further warranty against this issue.

 

 

[BobM]

Thanks both. Scott, the £400 extra seems good value in the context of removing the diff and refurbing.

Yes, was wondering whether CC would supply an open diff, the 420R does indeed come with LSD as standard. I don't see them warranting the LSD, they will just argue that it's standard wear and tear given that the manufacturer, Titan, actually specify a service life and rebuild interval :(

[David Brown]

As I currently have the diff out of my car, I can confirm my 2008 CSR260 has a Quaife fitted. Seems like the sensible choice for a primarily road based car with no additional maintenance requirements - as opposed to the prop shaft which has grease nipples but was boxed in with a plate and 32 rivets.