BMW/Titan LSD Viability

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ScottR400D
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Of course. I wouldn’t think of following any of those courses, life’s too short!

But I don’t agree that they don’t have the resources; They’re clearly well aware of the issues and they have at least one solution to hand. 

It’s possibly more of an issue figuring out justification for change without being incriminated by their past, that will challenge resources.   

 

 

Geoff Brown
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According to the letter CC have limited extra resources to bring to bear on the problem!

Remember some years back the BMW diff output leak saga?
It took time & some pressure for CC to recognise that there was a problem.  At the time it was not at the top of the 'to do' list. The limited resources decided just to adjust the oil content from overspill, 1.1L to a measured 0.8L.  Not exactly a mechanical fix as I suspected some of the OE fit seals were of a poor standard.

The re designing of the prop shaft to accommodate the BMW drive flange would have helped immeasurably canceling out shaft rotation irregularity that always occurs. Again a problem that affected the BMW diff but not the Ford.

Should I dare mention the 620 cooling saga as another episode where 'limited extra resources' come in to play?!

On reflection we, all of us here in this post, have carried out their duty as club members & owners to bring the Titan problem to the fore so as to warn others & to be able to flag up to Caterham however they decide to deal with the problem.

If this was an aerospace problem concerning a critical component - I see the diff as such - then fleets would have been grounded awaiting a well thought out & engineered fix. Yes aviation is incredibly safety orientated & has large resources but in scale CC should approach things the same way.

 

John Vine
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Re #309:

Thanks, David.  My car is early 2008 as well. Presumably the best way to find out what CWP is fitted is to dismantle the diff and then ask an expert?  I'm not proposing to do that, but when Phil Stewart refurbed the diff in 2014, he made no comment either way on the source of the CWP.

JV

David_Long
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A little more feedback on my the Titan diff - I ordered some new Belleville springs and bolts from Titan (mainly as a precaution) and I put it back together. As a reminder this is an early 2013 sintered plate version. 

https://youtu.be/OUWsxA1CY2I

The Titan part is very straight forward engineering, but perhaps the Sierra diff is a little more daunting. Certainly the crown wheel and pinion needs some knowledge to set-up from scratch - but you can just mark it up and put it back together as it was. Out of interest, I went through the Ford procedure (found in their manual) and it returned to the marks as Road and Race had delivered to me. The bearing pre-load is quite large so you really need the tool that engages the castellated bearing carriers.

The BMW diff is an unknown to me, but in the process of doing this, it has become relatively clear that there are few (if any?) carbon plate Titan Sierra diffs out there - although there might be exceptions, the shift to carbon was after Caterham adopted the BMW diff. This explains why the Sierra Ford diffs don't exhibit the same problem, and sintered plates are a route to fixing the issue. These were the original type and have, in my experience, very good durability. 

ScottR400D
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David, you may be right and the carbon plates were an effort to reduce the noise which may be made worse by the BMW steel casing and mounting method? Though Phil Stewart did tell me that there were also two sorts of carbon plate and the earlier ones lasted better than later ones.

The sintered plates may be more durable but, for me with a BMW diff at least, the noise and banging/grunting was just not acceptable in what is mainly a road car.

Geoff Brown
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Irrespective of carbon or sintered plates the Titan service schedule still prevails to a certain extent especially where the BMW unit is concerned.. To deviate from this could court disaster. The only way is to monitor the LS unit health on a frequent basis if one does not want the habitual nause of dropping the diff every 12 to 18 months. Of course dependent on use & mileage. 

The issue with the Titan has always been with the BMW unit & not the Ford. For whatever reason the Titan is best suited to the Ford giving exceptional longevity & serviceability.

CC have admitted that carbon plates were introduced to the Titan in the BMW unit to reduce noise which they realise now was a big mistake.

Quote: 'Ironically, carbon plates were introduced to reduce noise, but we switched back to sintered plates some time ago (probably 2018 GB) - when reports of premature wear first started to appear, although they seemed few and far between, and also grouped around a particular duty-cycle of the car. I continue to have very few reports of issues but understand anecdotally (Tech Talk ? GB) that it is a wider problem than first understood and am committed to finding a solution.' End quote.

ScottR400D - My  enforced immobility ends 25th November so after re establishing the oil level in the diff I will be out for a test drive in the window of two days weather that appear to be available after that date. 

Will report back - then SORN for three months.

Bob Shelley
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One of the issues that this thread has thrown up is that it is difficult to establish which LSD internals a car has. Does anyone know how to tell without removing the driveshafts for the "Angus Davidson" test. Are there any stamped codes on the outside of the Ford casing?
My car is a 2008 R400D with 25k miles since new. Does anybody know what type CC were fitting then?

David_Long
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At that date it should be the Sierra 3.62 Diff with Quaife ATB. If your car 'ticks' as you push it then that will confirm the ATB.

7 wonders of th...
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On that year it could also be an AP Suretrack too....

Geoff Brown
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The only hopefully positive way to ascertain what lies inside a diff is to enquire with the CC Archivist who hopefully will find the original factory build or spec sheet for the car.