Winter Project - Titan LSD project

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7 wonders of th...
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Whilst there is most slippage at low torque inputs, the LSD works hardest at WOT in low gears this is when it is subjected to maximum torque, slippage on a road car should not adversely affect wear and durability providing the design is correct.

Please consider that the preload on these is significantly lighter than that of tintops which frequently cover very high mileages without issue,

also consider the permissible movement of the pack in this design and its affect on the bellevilles which regularly fail, the area of the clutch plates, this affects durability and impacts upon operation, the increased area allows for a softer engagement and much better transition.

Please don't fail into the trap of believing all items on our cars had been thoroughly tested before being used and put into production as sadly this is simply not true, from your point Mark you have already encountered radiator problems with poor quality units and badly engineered mountings which you have had to rework, and then there's the 620 cooling system...... there are many examples of 'let the customer do the testing for us'.....

Perosnally I'd be returning the unit to CC and over the winter send your final drive to Steve for a Tracsport, leaving you more time and money to enjoy your car.

 

ScottR400D
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As far as Mark is concerned I wouldn't be at all surprised if when he strips his Titan he finds it 'serviceable'. It's not done many miles and is likely to have sintered plates. (Based on the age of it and the noise it makes)

I may be wrong but I think Mark is looking for a way to stop his diff clunking and knocking, which, as he has shown in the past, is a problem. I've seen the videos he's posted and it clunks and bangs like mine did, which was unacceptable to me, but is no longer an issue with the Tracsport. 

I've been chatting to Steve P this morning. More than 100 7s now fitted with Tracsports with happy owners. The proof of the pudding etc........

Anyway, each to their own. 

Geoff Brown
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I do not intend to become absorbed by this post or offer extensive counter arguments after BMW/Titan LSD Viability | Lotus Seven Club (lotus7.club)

Suffice to say that the carbon plated variety of Titan was of 'chocolate tea pot' quality. A bomb waiting to go off at whatever mileage it decides. Low or high.

The sintered plate Titan appears to be far more resilient but the other internals not so as in the carbon variety.

The Titan though used extensively by CC & other vehicle manufacturers is by the admission of the RR transmissions web site built to an affordable budget. Make of that what you will.

The SPC LS unit is a quantum leap up from the Titan & after a year of use cannot fault it. Only time & mileage will tell !

I am happy with the decision that I made to go the SPC way. Every time I drive the car reinforces it.

 

 

CtrMint
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I may be wrong but I think Mark is looking for a way to stop his diff clunking and knocking, which, as he has shown in the past, is a problem

I'm not attempting to solve the clunking, I've accepted the noise, while excessive, they all do that.. right. Mine has been confirmed as the sintered plate one, which apparently accounts for the higher lefts of annoyance.

I figured 5000 miles, the diff needs maintenance, either preventative or remedial, I'm not sure which.  So time to remove it and assess.  I want to be more self sufficient, as I mentioned shipping on and off island is expensive and a PITA.  To that end I'm putting a new one in for the next 5k while I learn/assess the current one.  I think that's being lost in the thread.  I want to compare like for like, I think its better to learn. 

The learning thing is really important here,  Today for example, I've screwed up some how.  The wife and I started the Taffia FnC run however, we didn't make it to Aberdovey.  Having fun through the Black Mountain pass my steering moved a spline.  I recently did some maintenance on the top steering bush, and some how screwed something up.  I had the torque wrench out on all the bolts so not sure what I've done. (we did stop and i hung on the uj nut)  The point is, I need to get better...  It's cost me some fish n chips today,  (we didn't carry on as I'd little confidence in the steering and didn't want to be a slow obstacle for everyone else and ruin their day).

If the process is more expensive, and even if I end up long term with an SPC diff, that's fine so long as I gain knowledge.

 

Caterham 420R S3 Lotus Toxic Green,  Caterham 620R S3 Exocet Red. Blog: https://www.caterham7diaries.com
ScottR400D
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Fair enough. Yes, at 5k the Titan would be due a look at. 

CtrMint
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Well today's learning has been an interesting one.

  1. Don't trust the assembly manual you were sent with your kit!

 20Nm for the steering UJ as shown in my kit manual.

 

Then revision two available from CC, now 32Nm

grrr, slightly off topic I know, but it relates to the knowledge aspect etc. 

 

Caterham 420R S3 Lotus Toxic Green,  Caterham 620R S3 Exocet Red. Blog: https://www.caterham7diaries.com
ScottR400D
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Hmm, not like CC to get design parameters wrong....... Wink

I see that the I7Network is now also running a thread on the diff. They appear to have been talking to CC and quote them as saying:

'on the serious matter of longevity of the carbon plate – type differential, this is something that I am trying to dedicate resource to investigate. Ironically, carbon plates where introduced to reduce noise, but we switched back to sintered plates some time ago when reports of premature wear first started to appear.............I continue to have very few reports of issues but understand anecdotally that it is a wider problem than first understood and I am committed to finding a solution'.

'We do not want to make ownership onerous, but in the respect of the differential it is increasingly apparent that the team at the time got this wrong....it needs to be corrected and I would be first to admit it is taking an extraordinarily long time'.

Make what you will of that. They seem to be implying that it's just the carbon plates that are an issue, which just isn't true. If it were then the last quote wouldn't be necessary. The 'do not want to make ownership onerous' comments refer to the, only recently made evident, frequent maintenance requirements which was never made clear to purchasers. If the sintered plates make the LSD fully serviceable why would that be needed? 

Anyway, I know opinions are split, I am really going to try to stay out from now on. I've made my view clear and I really don't have a problem any more. 

  

 

7 wonders of th...
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I'm not attempting to solve the clunking, I've accepted the noise, while excessive, they all do that.. right. Mine has been confirmed as the sintered plate one, which apparently accounts for the higher lefts of annoyance.

 

Actually no they don't, if the LSD is correctly designed and build and it's been installed into a correctly set up final drive,,,,,

 

Sorry to hear you had problems today, glad you got it sorted.... Thumb Up

 

CtrMint
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Cheers Neil, 

It did wreck the day though, we opted to leave the route very early, so didn't see much of the joys of the trip.  Ahh well chalk it up to experience, look towards 2022 and some track days hopefully. 

I'm going to pull the entire steering out along with the diff now.  I want to see if the movement caused any damage to the splines etc.  

Caterham 420R S3 Lotus Toxic Green,  Caterham 620R S3 Exocet Red. Blog: https://www.caterham7diaries.com
aerobod
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Are you sure it jumped a spline Mark, as opposed to the rack moving in the mounts or the top clamp not being square on the clamping flats between the inner and outer steering column? Often the pinch bolt will pass across a flat or indent in the shaft that would prevent any rotation of the splines, unless it is a machined groove all the way around the shaft that the pinch bolt locates in?

James