270r lsd problem

[Doctor]

Size on the inside. Sierra diff is able to handle power outputs than the version of BMW diff CC uses.

[Doctor]

SPC Tracksport for 7" Sierra casing is much bigger than the version for BMW diff CC uses. Titan LSD handles the power OK when working, unfortunately due to a engineering flaw in is very prone to fracture it's Belleville pre load spring and that makes the diff behavior erratic and more prone to slip. 

[ScottR400D]

#51 I understood that CC only use the Titan LSD, whatever the housing? 

Are you saying that they fit a larger LSD in the Sierra housing, which would make sense because that’s what’s on the 620 and it seems to last?

I cant make head nor tail of what they offer on the website because they don’t put proper descriptions but they seem to have a lot of options. 

[Doctor]

Not sure about that. Both LSDs might be from TITAN, but it is not going to be the same diff.

[ChrisC]

Just for reference, the rebuild kits for the Titan LSD on their website seems to suggest the Sierra and BMW use the same rebuild kit. 

 https://titanexpress.co.uk/products/lsd-rebuild-kit

[7 wonders of the world]

The Titan is not capable of handling the torque though hence the number of owners suffering burn out of plate prematurely wearing out.

The broken bellevilles is just down to very poor engineering design.

 

[Doctor]

https://caterhamparts.co.uk/differentials/4453-caterham-diff-3-91-lsd-assmebly.html?search_query=differential&results=45

 

https://caterhamparts.co.uk/differentials/4795-diff-assy-3-62-with-lsd.html?search_query=differential&results=45

[ScottR400D]

I’m not sure what you’re trying to say there Doctor?

CC show on their site several different differential options, open and limited, but there’s never any information about what’s in the housings. 

All we know is that there are the Ford and BMW housings with their Ford and BMW CWPs. 

What actual differential mechanisms are in there isn’t that clear but it seems that most of the limited versions use the same Titan LSD, certainly the BMW options. 

Presumably open versions use the original Ford/BMW mechanisms.

  

[ScottR400D]

ChrisC, you’re right it does suggest that. 

I’m puzzled, if that’s the case, how the 620 manages to run the diff more than 5 minutes!

Presumably, the Titan LSD was used in the Ford housing for many variants until the BMW diff came into use though, so the rebuild kits could be aimed there. 

I hadn’t seen this recommendation before:

“Titan recommends that the LSD is serviced every 12 months, race season, or every 10,000 road use miles”

By “serviced” I guess they mean rebuilt.

 

[Doctor]

Hi Scott - this is just to show the difference in size or the casing. BMW type 168 diff has a bracket on it to replicate the mounting points of the 7" Sierra diff to be able to be fitted to Caterham chassis. CC uses different back plate (BMW usually has air "oil cooler" at the back) in order to keep the size compact. Seeing SPC Tracksport going in the Sierra casing (how tight the fitment is side to side) I would be very surprised if you could squeeze the same unit into the BMW 168 casing. The TITAN LSD unit is way smaller. 

[ScottR400D]

I see, yes you’re right.  

According to Steve at SPC about his LSD, and I quote “The internals are very slightly smaller in the BMW it's a question of packaging”

I don’t think it's all down to size; design and materials matter too and I am told the SPC is much better in those areas. 

 

 

[Geoff Brown]

After some discussion above in 'LSD magnetic plug' thread where the in service life of the Titan LSD irrespective of the plates fitted was discussed I have contacted Steve at SPC.

As suggested SPC do have an LSD that fits in the BMW casing. The Tracsport LSD is £1150.00 + vat. Side bearings, seals, backlash & preload set up £250.00 + vat. Any other wear & tear that requires attention is at cost after assessment. 

So one could be looking at a bill in excess of £2000.

From what I have read in this thread it could be money well spent as the Titan LSD appears not to be entirely fit for purpose. I do not want to have to keep dropping the damn thing on a very regular basis just to get the preload sorted.  

My R400D wields 220bhp &160 ft/lbs torque so I want an LSD man for the job & one that is almost 'fit & forget'. 

Dropping my LSD out as part of a winter project on the back end. Probably October.

Does the revelation about the SPC LSD mean that Steve could have a tsunami of custom?

[ScottR400D]

Geoff, have you read post 38 in this thread? Steve's BMW LSD is what I've been running for a few weeks.

[DJ.]

Not at that price!

I have a Titan in a Sigma 125 (it gets a relatively easy life) it has been in about 9 years and done about 35,000 miles. It sounds fine, seems to function normally and I haven't seen anything untoward on the magnetic filler plug when I have changed the oil every two years.

Thanks to these threads, I have checked the preload and it is down to 20Nm so it is due a service. I'll take it out over the winter and see what the service cost is, but Road and Race  have said around  £250 if nothing serious. If that's all it is, I'll rebuild it. If it is a lot more, I will either put my spare open diff in or consider other options.

As I don't race, I think an ATB might be an idea as they don't require servicing and are half the price of the Tracksport. I do like the way the car drives with the Titan though.

Duncan

[ScottR400D]

Duncan, yes, I would think you'll be fine with a 125bhp/120 ft lb engine. I have mates with 310s, 150bhp and their Titans are OK at 10/15k miles. It seems to be R400/420 that seem to knock it out quickly, if used hard.

I'm surprised that RandR quoted £250 though, the LSD service kit is about that, plus time. I was quoted £450 which turned into £900 or so because the disintegrating Titan had damaged the bearings too.

From my invoice, excuse formatting.

BMW Caterham Differential Rebuild,

Rebuild with New Bearings and Seals. Reset LSD 1 £450.00 £450.00

Titan Rebuild Kit

Sintered Plate Rebuild Kit

1 £270.00 £270.00
 

RRTOil LS90

LS90 - RRP £15.00 + VAT

2 £14.25 £28.50

Subtotal:
£748.50
VAT 20%:
£149.70
Total:
£898.20
Payment on June 8, 2020 
£898.20

[DJ.]

Wow, that's very close to a new Titan! I wonder if there is a difference in rebuild prices between Ford and BMW diffs?

I was quoted £150+ vat for the strip down and rebuild, I think mine had sintered plates as it was supplied by Road and Race not Caterham, so hopefully it might just need new washers and resetting and the extra parts sounded like another £50 to £60.

If it adds up like yours, I think I will just put the open diff back in as I don't really need the lsd, it's just more fun for Dunsfold and Car Limits days

[ScottR400D]

Yes, it's close to the cost of. New Titan LSD, but as you can see there is cost in the bearings and labour that wouldn't be included with a new LSD. Mine was the worst case scenario, of course.

You might get away with a simple rebuild but I would have thought a plate rebuild kit would have been a reasonable expectation at your mileage.

Please let us know you get on!

[DJ.]

I will  

[Geoff Brown]

Scott -  Yes I did read #38 several times to get the point. That is why I contacted Steve Perks & inquired about his LSD.

To some might be a tad expensive but I am now at the point where the inheritance gets spent - irrespective. I do like driving my R400 so from your narrative #38 I have made the decision. 

As you say lower rated cars may lengthen the life of a Titan but myself as I have mentioned with 220bhp -160 ft/lbs I do not want to have to drop a Titan too often for a service. 

I know my LSD is now 7 years old/20000 miles but how long has it been deteriorating?  The noises started quietly at least 3 seasons ago at about 13000 miles getting gradually louder.  I put it down to 'one of those Caterham things' until I investigated by doing the checks. I have changed the oil several times during that interval trying to find the 'right oil' & although slightly dark never really gave any warning signs.

What oil does SPC recommend the LSD should be run on?

Please do give us an update on running the SPC LSD before the end of the season in a new post?

[Doctor]

SPC Tracsport oil is 75W-90. As it doesn't slip, the temp stays at about 85'C, so no need for 75W-140 that CC recommends for Titan. 
 

beware - the oil has to have the LSD additive, otherwise the LSD slips.

[ScottR400D]

Steve told me any good 90 GL5. As said above, no need for thicker stuff. 

Measuring the external temperature after a good run my diff was around 75c. 

[7 wonders of the world]

Igor,

Your getting confused as to how the additive works....

The LSD additives, either included in the oil you buy or as a separate bottle are deigned to allow the clutches to slip more easily over each other, with this you get the chatter a he clutches grab then release and set up a judder within the packs

How do you know the temp holds 85 degrees, have you added sensors on in your final drive...?,  increasing the viscosity of the oil will not make it run cooler either, race final drives have for years have oil pumps and oil coolers fitted, many Mazda and BMW come in OE form with cast cooling fins in the casing too even for road use.

[Doctor]

Confused is my middle name.

I have a temp gun, so easy to measure temp. It is very crude, but all you need is a trend.

No, the thicker oil is not going to cause to run in cooler, but is will be slightly more resilient to heat cycles.

[aerobod - near CYYC]

Typically a 75w90 GL5 oil is the same viscosity at 100°C as a 75w140 GL5 oil is at 120°C. Hard track work may make the 75w140 the right choice, my diff certainly stays quieter after hard sustained use on the track with the 75w140 compared with the 75w90.

I don't have accurate temp measurements of my R400 diff on the track, as the cooldown lap certainly reduces the temp quite a bit before I can measure the temp, but as a reference my son's Corvette Z06 was seeing transmission and diff temps of 135°C on the same track (they tend to normalise to the same temp due to being in a single transaxle unit) compared with 90°C during spirited road use, as he receives a temp sensor and transaxle overheat warning when over 130°C.

[7 wonders of the world]

they are he sort of numbers I'm used to ..... well into 3 figures on the track, simple things like ducting airflow can help manage the peak temps