Mrp Posted May 24, 2021 Share Posted May 24, 2021 OK am I being dim !!!!! in neutral I turn one wheel and the other doesn't turn, in gear the opposite wheel turns in reverse is this good or bad ?Mrp Link to comment Share on other sites More sharing options...
Mrp Posted May 24, 2021 Share Posted May 24, 2021 #4237WOTW my original question was I did not want to have the car off the road for any longer !Mrp Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted May 24, 2021 Share Posted May 24, 2021 In gear the other wheel will turn in the opposite direction unless the engine resistance to turning provides less torque than the LSD preload (generally not the case). In neutral if the other wheel is not turning in the same direction and remains stationary, you have some preload. but it isn't very much. Best to have one wheel chocked on the ground, remove the other wheel and check with a torque wrench on the 42mm axle nut how much torque is produced by the preload when in neutral, below 20 lb ft indicates rebuild time. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted May 25, 2021 Share Posted May 25, 2021 Then you have already answered your own question ..!However with a little careful planning with your guy and Steve you could get this down to 2-4 week days and save your self a heap of cash Link to comment Share on other sites More sharing options...
Area Representative Geoff Brown Posted May 25, 2021 Author Area Representative Share Posted May 25, 2021 FORTY THREE PAGES, 429 POSTS & 29,146 VIEWS from October 2020 !I expected this post/thread to have expired by now but with the 'problem' still out there I guess it will endure.Have exceed 300 mile with SPC LSD. Still eerily quiet - well maybe a little background noise from CWP in certain situations - but delivering as it should without any dramas.. Link to comment Share on other sites More sharing options...
ScottR400D Posted June 16, 2021 Share Posted June 16, 2021 Now I may be putting 2 and 2 together and getting 5 but were you at SPC yesterday, Mrp? If yes, how did it go, when will you be up and running?From what I'm hearing Steve is struggling to keep up with demand for replacement BMW LSDs in 7s! Link to comment Share on other sites More sharing options...
Mrp Posted June 16, 2021 Share Posted June 16, 2021 Hi ScottYour maths was correct I was there with a new non LSD complete diff assembly for Steve to convert and me to pick up on Friday. He was doing another one before mine so he showed me how he sets them up in the casing with the big circlips that act as shims. He also explained the difference in setup compared with the Ford ones.I'm not sure if I hold the record for the lowest mileage at around 3K.I hope it gives Steve some good business.I would be grateful if you could give me details of the magnetic filler plug you used.The diff will be fitted in the car I hope next week by Nick Potter when he services and Mot's the car.Mrp Link to comment Share on other sites More sharing options...
ScottR400D Posted June 16, 2021 Share Posted June 16, 2021 The mag plug is a Gold Plug AP22. M22 thread, 26mm hexagon, available from Demon Tweeks. It's handy to have a 26mm ring spanner to fit. I've been in touch with Jason who's diff was the one before yours, he told me if someone else there with a 2017 car <4000 miles which I connected to you!Jason had someone else assemble and fit the BMW/SPC originally and it wasn't correct so Jason had removed himself and taken to Steve for setting up properly. It's back in and running much better now. Link to comment Share on other sites More sharing options...
Mrp Posted June 16, 2021 Share Posted June 16, 2021 Thanks Scott plug ordered.I didn't mention Jason as I wasn't sure he wanted to make it public until he had spoken to the other assembler.It was correcting Jason's diff that allowed Steve to explain to us both about the circlip/shims and how careful you have to be setting them up and he used my new one for comparison.It was an interesting couple of hours. I'm pleased Jason is happy with the result.Mrp Link to comment Share on other sites More sharing options...
Mrp Posted June 16, 2021 Share Posted June 16, 2021 Sorry one last question for Scott or anybody else. Steve said he was not fussed about which oil, has any one get any recommendations please. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 16, 2021 Share Posted June 16, 2021 Re #434 - do you know what spec they are using for CW&P backlash when selecting the circlip shims? BMW have used 0.05 to 0.20mm over the years for backlash in different 168 diffs, mine is 0.14mm at the moment. It also would be useful to know what bearing run out / side float tolerance they are aiming for. Link to comment Share on other sites More sharing options...
Mrp Posted June 16, 2021 Share Posted June 16, 2021 Hi JamesAll I can say is Steve said he sees them in different thicknesses and he has to grind them down with a surface grinder and occasionally shim them as BMW won't supply them to him.I'm not sure about the side float but I think he said 2.5 thou is what he likes to get them to. I think the shim/circlip he was using from Jason's diff had 0.14 stamped on it but he was having to skim it with a surface grinder.Hope this helpsMrp Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 16, 2021 Share Posted June 16, 2021 Hi MRP, if he can't get the local BMW dealers to sell them, they are generally available online, places such as Racing Diffs sell sets of them: https://racingdiffs.com/products/bmw-differential-backlash-adjustment-c-clip-set They are normally in the 3 to 4mm thickness range in increments of 0.02mm, so the one that was shaved down was probably 3.14mm. The only problem is that if the same bearings are used, shaving one down will probably require the other to be thicker to end up with the right tolerances in lateral position of the CW&P relative to the bearings. Link to comment Share on other sites More sharing options...
ScottR400D Posted June 16, 2021 Share Posted June 16, 2021 Steve aims for .0025/3". The diff he was rectifying yesterday was apparently assembled with the correct backlash but the circlips had just been put back in without correctly gauging the preload and was over loading the side bearing. That's why Steve grinds the clips, to get the right bearing preload. Wrong terminology, I know, it's a ball bearing etc but you'll get the gist. You'll know better than me James. Oil? I've used RRT 90 and Redline 75/140 GL5. No difference that I can tell. Some say the RRT quietens the Titan's cacophony but it wasn't my experience and the SPC doesn't need that anyway. I'm told the RRT does that because of a high level of friction modifiers. I think Steve's right, any good quality 90 GL 5 will be fine. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 16, 2021 Share Posted June 16, 2021 Re #437, on second thoughts 0.14 as the circlip thickness could be 0.14" or 3.56mm, probably indicating the diff wasn't as-supplied by BMW, but had already had a 3rd party put a non-BMW circlip shim in it. My BMW diff in the Caterham definitely has metric stamped BMW-sourced circlips in it. Link to comment Share on other sites More sharing options...
Mrp Posted June 16, 2021 Share Posted June 16, 2021 Scott thanks I'll use what you suggestJames thank you I'm now way out of my depth, but I will pass that website information onto Steve Link to comment Share on other sites More sharing options...
ChrisC Posted June 16, 2021 Share Posted June 16, 2021 Interesting a new "unboxing" 420R video posted on YouTube today shows a return to Ford Sierra diffs being supplied Link to comment Share on other sites More sharing options...
Mrp Posted June 16, 2021 Share Posted June 16, 2021 If you look at his blog he has ordered it with a sadev box so that probably why Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 16, 2021 Share Posted June 16, 2021 Definitely a used Ford diff casing, going by the wear marks on the top of the long bolt mount. Likely still has the Titan LSD core that is the same as the BMW diff in it, though. Link to comment Share on other sites More sharing options...
ChrisC Posted June 16, 2021 Share Posted June 16, 2021 That would explain it. Link to comment Share on other sites More sharing options...
ScottR400D Posted June 17, 2021 Share Posted June 17, 2021 Out of interest, Geoff Brown, did you ever get a reply to your letter to CC last October? Link to comment Share on other sites More sharing options...
ScottR400D Posted June 17, 2021 Share Posted June 17, 2021 I see over on Pistonheads Caterham forum someone has posted about having bought one of the gearbox spacers that tilts the engine down at the front, hoping it is going to remedy, as he puts it, "banging and clattering on low speed turns" of his 2018 420R. He says CC have introduced this spacer to 'virtually eliminate" the banging and clattering.Is that really what it's designed to do, because I can't see how it can? I can see how it might ease some prop vibration but not stop the normal Titan noises. Anyone on here? Link to comment Share on other sites More sharing options...
Mrp Posted June 17, 2021 Share Posted June 17, 2021 Hi ScottI think you need to ask ChrisC on here as I think it was mentioned by him. Link to comment Share on other sites More sharing options...
ScottR400D Posted June 17, 2021 Share Posted June 17, 2021 Yes, it was but Chris didn't seem to think it was diff noise that it stopped, though he didn't say what he thought the noise was, that was cured: "'It seem in 2021 Caterham introduced a spacer to lift the tail of the Mazda gearbox 3mm. This stopped 90% of my noises, which was suspected by Caterham themselves as diff noise, but obviously not."I am assuming the "banging and clattering on low speed turns" is the usual Titan symphony. It would be interesting to really know what noises this spacer is helping to cure and learn if it might be possible to do something similar with the 6 speed. I've looked on the CC online store but they don't actually say what the purpose of this spacer is. Link to comment Share on other sites More sharing options...
ScottR400D Posted June 17, 2021 Share Posted June 17, 2021 Yes, it was but Chris didn't seem to think it was diff noise that it stopped, though he didn't say what he thought the noise was, that was cured: "'It seem in 2021 Caterham introduced a spacer to lift the tail of the Mazda gearbox 3mm. This stopped 90% of my noises, which was suspected by Caterham themselves as diff noise, but obviously not."I am assuming the "banging and clattering on low speed turns" is the usual Titan symphony. It would be interesting to really know what noises this spacer is helping to cure and learn if it might be possible to do something similar with the 6 speed. I've looked on the CC online store but they don't actually say what the purpose of this spacer is. 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