Winter Project - Titan LSD project

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ScottR400D
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Yes, carbon. 
 

Well it was........ Whistle

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aerobod
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Re #108, Peter, a couple of possible differences compared with my Titan.

1. The surface that the inside of the Belleville washers rests against seems to be flat as opposed to domed on mine, allowing 100% deflection, compared with 80% or so on the domed ends of mine.

2. The thrust washer for the side gear that is exhibiting heat marks doesn't have oil grooves in it, compared with mine (unless it was fitted backwards).

 

James

David_Long
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What is interesting from the photo is that the BMW crown wheel is smaller compared to the Sierra. There appear to be 8 bolts on the BMW and  there are 10 on the Ford, The BMW crown wheel is also recessed further back (I guess to get the crown wheel in the correct position), but the net result is a smaller diameter LSD casing in the BMW version. Although torque delivered to the wheel will be the same, it does suggest that the BMW is a higher stressed CW&P than in the Ford Sierra (ie the CW&P gears are smaller).

ScottR400D
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#113 James, that's interesting though I couldn't begin to explain why there would be differences. This is a 2015 car and those, as far as is known, are the remains of the diff as it came from the factory. 
 
IIRC your car is older than this one? So, assuming that the parts you received for your rebuild were similar to those you replaced does this imply that there were more design changes made than just the plates, at some point, which may or may not have been reversed now?

 

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ScottR400D
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#114 David, certainly with the Tracsport LSD the BMW version is slightly smaller than the Ford version. 
I understood that the Titan was the same size in both, and that the rebuild kits are identical but that may not be the case?

Can anyone confirm that? 

 

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David_Long
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The clutch and plates are billed as being the same in both BMW and Ford, but when I ordered parts, I was asked which diff I had, read into that what you like.  The Sierra version also has no holes in the top bearing carrier. 

And the there are some differences to the bushing at each end.  Whether this one has domed thrust surface for the Belleville spring is difficult to tell (I didn't check at the time) but the photo does not exclude that possibility.

ScottR400D
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Just to throw another thing into the pot this is what I've been told, I have no first hand knowledge, though it makes some sense:

The back plates of the original BMW housings were shaped to direct oil, flung from the CW, towards the front of the housing and onto the pinion and it's bearing. The CC backplate is not so shaped and there's a risk of the pinion and bearing being starved of oil under acceleration so the higher, 1.2L of oil, recommendation that was in place until a few years ago might well be the better option. 

I'd have thought that the CW would throw oil off at every point so the pinion and bearing would get it's fair share but I'm not particularly familiar with the internal arrangement in this respect. 

I'm not aware of pinion or pinion bearing wear being an issue so this may be a red herring but I found it interesting. I've never suffered from driveshaft seal oil leaks (famous last words?) so may revert to the higher level of oil. 
 

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David_Long
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This is pretty good at explaining all that https://youtu.be/9-yG3D3JBRs And yes, pinion bearings can get starved of oil and it's a very real problem. As said in another post, Ford spent a great deal of their resources to get this right and the Sierra diff has a profiled back and an oil gallery at the pinion end to  help allow oil to flow forward against the pumping action of the crown wheel. 

ScottR400D
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Thanks for that, very interesting. 

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Dan R
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As with all these things there is a lot of careful thought and research that goes in to the simplest items.  Once you start to delve into the finer details it opens into a huge topic!!  Fascinating.  

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