ChrisC

My point to "Billy.Whizz" is there are a lot of cars out there with the carbon plates which Caterham no longer use. Only Caterham know for certain how many cars, but it could be all R models from 2016 to 2018(ish). This will look like there is a problem with the part being used, but Caterham had already addressed this, mainly because they are starting to fail now in numbers.

Sintrax is Titans name for the sintered steel plates, so you are correct. Sorry I was using marketing speak from their website. For reference https://titanexpress.co.uk/collections/drivetrain/products/bmw-168-lsd

So it will have the sintrax plate differential, a change made in recent years by Caterham from carbon, I have been warned by the production manager at Caterham that the sintrax diffs are noisy but more reliable than the carbon plates. I am not worried about my diff, in my 420R.

There are owners that have had problem, and there owners that have had no problems. I know the spec changed in the plate material, what age car are you looking at?

A chassis ear is a electric stethoscope which allows you to drive and listen to the noise at the same time, if you know someone in the trade you might be able to borrow one. I once had a noise I could only hear on track day videos of my car, the noise came while changing gear, so it is possible the noise is only there when recording. Working on the assumption it's the prop angle thing, have you changed the diff spacers?

Most of the noises sound fine to me, but there is a noise I don't like. As you said, sound like CW and P, but I guess if it was CW and P it would be there all the time. Have you got access to a chassis ear to prove the location of the noise?

In the past oil has been proven to play a big part in the noise, from my own experience of a BMW diff 360R (with a Titan LSD) the initial kit oil was used to fill the diff, but at 1000 miles I changed the oil to the Motul 75w140 (the blue stuff) and the diff became more noisy. I know you know the oil you have now, but did you know what it was originally filled with?

Ok, but you have had your diff rebuilt by one of the countries specialists, and it's been given (now) a clean bill of health. Based on that being true I would have to say it's something I would have to live with. You can call it a characteristic of the car, based on the DeDion setup/design where the diff is secured to the chassis, in combination with an LSD that's not been design to be refined. If I had just had my diff rebuilt by the Phil, I would be happy to trust him, and be happy to live with the design of the car. That said I have owned road cars with straight cut gearboxes, and stupidly lumpy cams, which made street driving noisy and challenging, but I have loved these cars far more than any refined tin top rubbish offered by main stream manufactures these days. Obviously it's your car and your opions that matter, you can look for a quieter diff / diff design, but how quiet are you going to get it? Have you seen or driven an equivalent spec car that's making you think its unacceptable? If you have I would be checking every element of the cars spec to confirm, from the oil used to the diff internals used, age of the drive shafts, age of the mounting bushes, carrier design, backplate design, etc etc... The quest for a quiet LSD is very long based on the post history of blatchat.

Billy, there is a lot of Caterham haters on this site, its always their fault that Ford stopped making the Sierra (27 years ago), not that the Ford diff was quiet. When the BMW diff was released loads of owners converted due to noise. The fact is the diff in a BMW or Ford is much better insulated, in comparison to a 420R, and Caterham don't engineer their cars to trundle to the shop and back in silence. Basically they don't consider the word "refinement" as part of the experience. I have driven Caterhams for 11 years, with no diff problems. I did have a suspected diff problem with my Sigma 150, which turn out to be a driveshaft spring. Also I see so many owners driving their cars without ear protection, this is such a stupid thing to do, your hearing can't be repaired. Once you have decent hearing protection you find worrying about the diff noise is a thing of the past.

On the first page of this thread there is a picture of the 620 stat housing. Isn't the cut out at 6 o'clock providing a cooling circuit while the stat isn't open, all be it through the radiator? Without a picture including the stat it's difficult to tell.

PS The gold caliper is a reconditioned Ford caliper. The silver one looks like a Caterham caliper.

Bottom / second photo Brett. There was more meat on the original Ford calipers compared to the new Caterham items in this area, this is why the Delph rear pads rattle in the Caterham calipers. The Ford Sierra workshop manual confirms the spring location.

Just from reference CP4970-133 looks to be the replacement part number for the current AP Calipers.

Not removed a OBD bracket before, but I can confirm my 420R with a factory fitted battery isolator does not have the OBD fitted behind the knee panel, unlike my 360R which didn't have a battery isolator. The OBD port is just tie wrapped to the steering column.

What age is you 360S and has it got the optional upgraded front calipers?

Being a 2019 car it should be a new style sensor (not show in even the latest release of the build manual last week). This new sensor likes to sit a bit closer to the trigger wheel than the older sensor. As already advised I bet this can be solved with a combination of cleaning, gap setting and earth moding. If it fails at 80mph its possible that its always been like that, its only tested up to 70 mph during the IVA test, and most onboard footage I have seen from academy races have the speedo disconnected. If it helps this is the new sensor and earth mod fitting https://caterham420detailedbuildblog.co.uk/2020/01/25/speed-sensor/ and this is how I tested it https://caterham420detailedbuildblog.co.uk/2020/03/12/speed-sensor-testing/

So the real question is, what oil is it? There is a lot for it to be clutch fluid. You should be able to tell if it's clutch fluid by the feel. The engine oil from the dip stick looks darker than the leak, which makes me think it's not engine oil. That leaves gearbox oil, but you should be able to smell it. If you can't smell it, maybe you can get someone else to. If it was my car, I would clean all the leaking oil from the bell-housing; then I would run the engine. Let it run until the cooling fan kicks in. If the leak reappears with the engine idling, then I would suspect engine oil leak, either sump seal to engine, or crank main oil seal. If the leak does not reappear, then take it for a short drive. If it appears after that, then I would suspect gearbox. Look at the fill plug and reverse switch on the side of the gearbox (difficult, I know)

Time to swap to flexi lines I feel.

You can remove the ear with the drive shaft and disc in place. If this is to removed the diff, I would Loosen the Prop Shaft bolts. Remove the Rear Calipers Remove the Ears (Complete with Disc and Drive Shafts) Remove A Frame and DeDion tube Finally Remove the DIffI know this can be done without removing the tube, there was a post on here.

Maybe a Ford one would work http://www.fordopedia.org/parts-catalog/sierra-mk1/C1.10

Mine I was sourced from a drive shaft that had been replaced for other reasons. One of the advantages of using a specialist that runs a race team.

Unfortunately not 100% sure before mine was discovered by Boss Racing. In think its on one end pushing on the shaft itself, so a simple fix (if you can get the part). My original post https://www.lotus7.club/forum/techtalk/road-speed-clonk-what-solved

Could also be a driveshaft problem, there is a spring that can break. Makes a terrible noise when it goes, but is for some reason intermittent. Had that on a 2011 Sigma car a few years ago, so don't assume diff straight away.

It is engine oil or brake fluid from the clutch release bearing?

Either way, being a kit build you going to need to do the work to resolve. Caterham will repair or replace the part that's failed, but that's as far as the warranty officially goes.