Clive H Posted July 22, 2018 Share Posted July 22, 2018 Seriously, has anybody got a non LSD Sierra diff 3.38 for sale which is known to be quiet!I'm getting fed up with the chatter and whine. (from the diff!) Link to comment Share on other sites More sharing options...
SM25T Posted July 22, 2018 Share Posted July 22, 2018 Remove it and take it to a specialist like Road & Race near Sevenoaks, or SPC for overhaul. Link to comment Share on other sites More sharing options...
Clive H Posted July 22, 2018 Author Share Posted July 22, 2018 Hi.Yes I know but can they be certain that it will be quiet? I don't think so!Mine has only done 4K miles and has been noisy from new so I think its CW & P change needed. ( for an older set maybe).So I'm really looking for a "real" sierra diff, not a CC copied parts one.But thanks for your interest.Cheers Link to comment Share on other sites More sharing options...
SM25T Posted July 22, 2018 Share Posted July 22, 2018 Well they are the ones to advise .... and can make it quiet. Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted July 22, 2018 Leadership Team Share Posted July 22, 2018 I did a bit of digging into the diff situation a few years ago and, whilst I was mostly interested in LSD specs the fundamentals of what I found out apply here - and they include the fact that all Sierra diffs in recent years have not been 'new' but are essentially reconditioned units, and that this can lead to noise issues that cannot be easily resolved.My notes from the time, back in 2015/16 (in case they are of interest) include the following points: Traditionally, the Ford Sierra diff has been used in all manner of Caterhams. However, it cannot be sourced new and therefore all units in recent years have been reconditioned, but the problem with the reconditioned units is that (without access to OEM factory equipment) they are inherently noisy…. So a few years ago, the decision was taken to replace the Ford diff with a BMW diff, primarily to reduce noise levels. The BMW diffs are heavier, though, as the housings are cast iron (painted black) rather than the alloy (silver) colour of the Ford units. The BMW unit does have a torque limitation, though, (I think it comes from the BMW 1 series 118/120) so in very high powered applications (like the 620R) it has to be replaced by the Ford unit (inherently noisy but at least it's strong…) All diffs (either Ford or BMW) can be fitted with a LSD pack; most recent units carry a carbon-plate LSD pack made by Titan. Some diffs (and this may apply to the Ford unit in the 620R) carry a Quaife LSD unit which works on a different principle (ATB - automatic torque biasing). The LSD units can be quiet in operation or can 'chatter' or 'clack' a little in operation. Irrespective of type (Ford or BMW diff, Titan or Quaife LSD) it seems that all of the recent high-power cars are fitted with the diff struts. This seems to be in response to a large number of cracked diff casings and failed diff carriers in service. You can visualise how the struts work; they fix either side of the diff (to the mounting lugs at the top) and pass through the boot floor and fix to the cross member at the top of the bulkhead where the inboard seat belt fixings are. The struts provide a very considerable bracing to the installation (they react, or resist, the torque loading that is otherwise trying to 'tear' the diff or its carrier from the car). I have heard people say that there are no reported incidents of diff or diff carrier failure once the diff struts have been fitted. However, they do provide a very efficient path for noise transfer into the car and so add to the general levels of transmission noise.James Link to comment Share on other sites More sharing options...
mic Posted July 22, 2018 Share Posted July 22, 2018 Only 620 R uses the Ford diff unit fitted with a Titan LSD, along with 420 race cars. Cars with BMW diffs do not have diff struts. Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted July 22, 2018 Leadership Team Share Posted July 22, 2018 Thanks Mic - helpful to have the additional detail.But - my car (2012 factory build sequential R500) is fitted with the BMW diff and definitely has the additional struts/braces...James Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 22, 2018 Share Posted July 22, 2018 You should be wearing ear plugs anyway! CC have some cheap 3.38 recon diffs in clearance.Ian Link to comment Share on other sites More sharing options...
mic Posted July 22, 2018 Share Posted July 22, 2018 They are not fitted anymore James. Link to comment Share on other sites More sharing options...
Leadership Team Shortshift Posted July 22, 2018 Leadership Team Share Posted July 22, 2018 Got it - understand.And just thinking... If you spec the sequential option in a non-620 car (I think that's possible, for instance on a 420?) do you then get the Sierra diff or does that get fitted only to the 620R? I'm just curious to understand whether the diff struts/braces get specced with the sequential option (ie: non-sequential = BMW diff and no brace; sequential = Sierra diff plus braces)?James Link to comment Share on other sites More sharing options...
Clive H Posted July 22, 2018 Author Share Posted July 22, 2018 Wow. I didn't expect that!I seem to have re-opened an old can of worms!Maybe this shouldn't be in the "wanted" section! But it's great to talk and get some new ideas in this old problem.For competition use its not a problem but on long road trips it gets VERY tiring.I assume that my diff internals are almost certainly not original Ford parts and that may well make it impossible to silence.I will talk to Road and Race again and see how confidant they are about losing the worst of the noises.From what I understand, the best way to cure this is to fit a genuine old sierra unit. Hard to find these days though.Clive Link to comment Share on other sites More sharing options...
Clive H Posted July 23, 2018 Author Share Posted July 23, 2018 I think the CC ones will be the same as mine i.e. copy parts and badly set-up! But thanks for the infoClive Link to comment Share on other sites More sharing options...
Tom_Arundel Posted July 23, 2018 Share Posted July 23, 2018 My first diff was so loud that it could be heard 1/4 mile away above the engine noise...that went back to CC. The next was better but still noisy so...1 I realigned the top mounting bolt holes in the diff, (they are 2-3mm out as standard and preload the bushes)2. I turned the crown wheel in by 6 notches.2. I filled the diff with Redline heavy shockproof (red) oil (easiest option for some effect)Result...almost silent. If you don`t mind the fiddling its worth the effort Link to comment Share on other sites More sharing options...
Clive H Posted July 23, 2018 Author Share Posted July 23, 2018 Hi.Well I certainly don't mind the fiddling.That's all good info.Can you give me some more detail.Actually I have been looking for a spare castellated bearing carrier as a template so I can make a "C" type spanner.Then I can make adjustments in situ. I know that sounds wrong but from what you say, the odd notch (or 6) could be tried. I cant make it any worse!When you say " realigned the top mounting holes in the diff" I assume you mean drill/ream them out. Is that right? and did you do that in situ?Also I assume you screwed in the LHS (nearside ) bearing carrier.i.e. the crownwheel side.ThanksClive Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 23, 2018 Share Posted July 23, 2018 Clive,The individual teeth on the bearing adjusters are quite easy to snap off which I think could happen with a C spanner arrangement on one tooth - Perhaps make the tool with 3 or 4 prongs to engage?Ian Link to comment Share on other sites More sharing options...
Clive H Posted July 23, 2018 Author Share Posted July 23, 2018 Hi. Yes I agree but I was thinking many teeth in a semicircle.I dont know how to insert an image otherwise I would show you a drawing.CheersClive Link to comment Share on other sites More sharing options...
Area Representative Kingsley Young Posted July 23, 2018 Area Representative Share Posted July 23, 2018 CliveI know where you are coming from, I had mine rebuilt by Road and Race about 2 yrs ago, the diff itself was very noisy, add to that the chatter of the LSD when you lift off, was bloody awful!Interestingly when they stripped it , all the main parts other than the lsd were patten parts , this would have fallen into place regarding the supply of Ford diffs, Caterham scoured the country looking for old Sierra diffs to refurbish. Mine was rebuilt in the end using Ford parts , the lsd though is still chattering from the lsd, but main drive is a hundred times better.i have a friend who considering doing away with the lsd, I can’t blame him !Kingsley. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted July 23, 2018 Member Share Posted July 23, 2018 I dont know how to insert an image otherwise I would show you a drawing.From a file on your computer? Start here and let us know if you get stuck.Jonathan Link to comment Share on other sites More sharing options...
Clive H Posted July 23, 2018 Author Share Posted July 23, 2018 Sorted thanksThe tool would look like this......Clive Link to comment Share on other sites More sharing options...
Tom_Arundel Posted July 23, 2018 Share Posted July 23, 2018 Clive, I sent you an email but it seems to have got lost in the post.Where are you? You can borrow my adjuster if you need it,,,,,It requires quite a lot of effort/torque to shift the bearing housings a short spanner won`t work. Link to comment Share on other sites More sharing options...
Wrightpayne Posted July 23, 2018 Share Posted July 23, 2018 Tom,from the pictures I’ve seen the normal tool isnt going to work with the drive shaft in situ? Is that the case with yours?ian Link to comment Share on other sites More sharing options...
SM25T Posted July 23, 2018 Share Posted July 23, 2018 I have witnessed mine being adjusted with the complete car on a ramp and all wheels in place. Link to comment Share on other sites More sharing options...
Clive H Posted July 23, 2018 Author Share Posted July 23, 2018 Do you know what type of tool they used to make the adjustment? Link to comment Share on other sites More sharing options...
SM25T Posted July 24, 2018 Share Posted July 24, 2018 It was a *long* spanner ... along the lines of that shown above that fitted into the slots. Link to comment Share on other sites More sharing options...
Alan Reeves Posted July 24, 2018 Share Posted July 24, 2018 KliveI changed my CSR dif from a quiet 3.62 to a 3.14 from Road and Race and I mentioned that I did not want to change and get a noisy one They were totally confident there would be no issue. Changed the diff and it was immediately obvious I had an issue but it was not a whine so much as a resonance between 50-35 on a trailing throttle... i then had a 2000 mile Italian trip to listen to it !However R n R prepared a replacement and the cost of doing it and I got a lovely quit one. A very strange situation with the resonance but R n R know what diffs are all about .There was no LSD involved FYI alan Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now