ChrisC

All this does prove is regular preload checks, oil changes and magnet oil fill plugs are an essential part of Titan / BMW diff ownership.

Hi Tony I would not be so down of the BMW 168, granted its only used for 4 cylinder BMWs, and that must be a dirty word in the BMW motorsport fraternity, but the vehicle weight must have an effect on the ultimate load the CWP components are under. I have been a member here since the BMW diff was introduced by CC, and I can't remember an instance where a member reported an open BMW diff failure, or the CWP has caused a failure. Obviously CWP sets have been damaged when ;-) other components have failed. Chris,

You are correct The BMW casing is machined to fit the Caterham diff cage. A Caterham back plate is applied to clear the DeDion tube. The Caterham diff cage uses the same bolts as the Sierra diff, so fitting the diff isn't the problem. The drive shafts and prop on the other hand is another question. Drive shafts are available from CC, at about £300 per side. The prop is more difficult, because I am not sure if a Mazda gearbox to Sierra prop was ever created by CC. Maybe a 620S uses it, but all other cars with a Mazda box (introduced 2013) will have been connected to a BMW diff (introduced in 2010/11 ish). If its available then it will be in the region of £260(ish). Why are you looking to change to the Sierra diff, is it because of the threads about the Titan diff? A 420R 2016 car will have originally had a carbon plate Titan diff in a BMW case, which unfortunately seem to be expiring. If I had a 2016 420R I would perform a preload check on the LSD to see where I was on the service life. Others has posted Phils wisdom from RRT, 40ft/lb when new, 20ft/lb rebuild needed and 15ft/lb impending doom. You then have a choice in cost order 1, Rebuild with Sintered plates (as per CC post 2018), but this will make a lot more noise than your 2016 carbon plate version. 2, Replace the LSD with other brand, probably where I would go, I will be looking from a LSD with molybdenum plates like the Tracsport. It will be more expensive than a Titan rebuild. 3, Convert to another solution. As a side note, the Sierra diff wasn't without its faults either. Many converted from Sierra to BMW when it was first release because of the noise they used to generate, so do your research. You don't want to jump from the frying pan into the fire.

What gearbox do you have, 5speed? Has there ever been a Caterham prop made for a Mazda 5 speed to Sierra diff? If not you might need a custom prop.

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

How much clearance difference is there between this magnetic plug and the original? I remember reading about all the back plate redesigns where the DeDion tube hit the diff back plate.

Its funny how the tides turn, if you read old posts on BMW diffs on here its all about how wonderful the BMW diff is after they swapped from Sierra units.

Wet was my first thought, but it does depend if the MAP sensor is open to the air, which I don't think is the case for a 125. The 1.05v is a 150 setting which has a mapping strategy based on TPS position. However the balance between TPS / throttle site and throttle stop at idle is where I normally look for hesitation problems on pull-away. You are looking for a biggest throttle opening at idle, but with a throttle site of 0. As soon as the throttle is touched, the throttle site should be greater than 0. If you make an adjustment, disconnect and reconnect your battery (easy with an isolator switch) before you retest. Tweaking the idle stop screw and the TPS position to achieve this is my normal approach, even if this means opening out the holes of the TPS sensor a bit.

CC or RedLine https://caterhamparts.co.uk/gauges/1705-gauge-o-ring-52mm-gauges-caerbont.html I would do the lot because they all tend to fail at the same time.

Was waiting for your reply because I thought you're the best person to comment on the process. Has your original thread been deleted? I tried to find it this afternoon.

Only to replace a faulty one, which is what I did. There is a difference between the reading they generate, but I can't describe it. All I can say is when I changed the speedo was strange, sort of tin top like.

Scott have you used a new one?

The Rover part number came from the box that was supplied with my 2015 Oct 360R kit and my 2019 Sep 420R kit. The Bosch part number is written on sensor. I used the Bosch part number to get a replacement for my Decat pipe. I am sure it be the same on your car.

I wouldn't replace the sensor like for like. The sensor Caterham introduced in 2018 as a replacement is much better at doing the job, is more stable and cheaper as well. Obviously you could source this elsewhere, but you would need someone to modify your bracket or make a mounting boss, so hence it might be cheaper and easier to just order from Caterham. The post 2018 sensor has a much smaller air gap, .625mm works perfectly.

PS Mine was a Rover Part MHK10006, but it carried a Bosch Part Number 0 258 003 229

Rob, without question replace the lambda sensor, regardless of cat or not. Without it your going to run rich (which I suppose is better than running lean). Given you are seeing a difference when connected it sounds like the sensor isn't dead, but contaminated. Either way it needs replacement. It effects part throttle drivability. The lambda sensor is ignored at higher RPM. As for the cooling, if your fan comes on only when stuck in traffic all is good with your setup. This wasn't the case for my car, it came on when the car was still heating up and ran constantly, at no stage did the fan switch off (until the engine was switched off). The fan switch on temperature was below the engine thermostat temperature. I wasn't alone in having this crazy configuration, but I have not read about it on any car since 2015.

82 vs 102 stat

Is your fan kicking in at 80, sounds like a early spec. My 360R was early spec, but it was supplied with a 102c stat, which meant the fan always ran. Disconnecting the lambda sensor will tell you if it's working or not (ie no change when disconnected means it's dead), but without the sensor they normally idle poorly. But you didn't say it was idling poorly, hence why I suspected it's post start warm up phase. I wonder if you also have a 102 stat and a 80 fan setting, meaning your fan runs constantly? Can you take a photo of the stat and post it? The length of the plastic hoses on the stat housing are the give-away. When you have the fan running and the stat closed and stop, I wonder if the stat opens (without the pump running) when you switch back on you have a shock of cold coolant, causing the ECU to go back to warm up.

Agreed sounds like a miss fire to me. You can swap the coil packs help diagnose a coil pack problem.

Depending on age of your 360R, your running temperature should be higher that 80C. The standard stat is 102C, however very early version may have had the 82C stat (Late 2015). As for the idle problem it's difficult to say. There is no diagnostic software, only live information from the sensors. So to diagnose the problem a live data capture would be needed. That said after a restart there is a delay before the engine idles using the lambda sensor readings. I think it's 30 seconds and the coolant has to be above 60C before the lambda compensation kicks in. I wonder if that's what your feeling.

Just to be clear, my wording is about "Fit for Purpose" and the way I have successfully had cars exchanged and/or received my money back in the past. Not about the modifications planned or undertaken. I think the solution Doctor has created looks to be the correct solution to the problem. But I would not modify any car that I purchased that is under warranty, especially if it has problems to be resolved, mainly because my pockets aren't deep enough.

Botched maybe, but approved it is. You have the tools, and you have proven your car cools whenever the RPM is over 2250 (ish). If you take the fix and prove its still not fit for purpose, the ball is in your court. You could even tell them that's how your going to test it. The location challenges where always present, considering and the industry standard is about 97 faults per 100 cars, or put it another way, almost all new cars will have a fault. I can't imagine CC is better than the industry standard, so you always where taking that risk buying a brand that's not represented with a dealer on the IOM. As for your dealer, I can't comment. However a long time ago I took great delight accepting a bankers draft for my money back on a new Golf purchase, where the week before the Dealer Principal call me a "F**king C**t, and I would never get my money back". Covid has affected many, 14 days quarantine is a small price to pay.

Or, and I know this is difficult to hear, actual take the car back to the dealer so the dealer / manufacture can look at the problem. Every time I have had a car exchanged, my first step in the process was to return the car to the dealer, where the faults was diagnose, and agreements reached. I didn't discuss the problems in public, or on forums. In all cases, admittedly sometimes with a little struggle, a settlement was reached. Now I know the problem is known, so diagnosis is a mute point, but the dealer must be permitted to see the car. I also can't understand the position taken on the CC modified thermostat fit, yes its untested, but its approved. If there are more complications due to its fitting, your CC warranty is still intact. Fitting your own thermostat is equally as untested, but doing so absolves CC of any warranty obligations. Even draining that car and removing the top hose would have implications for cooling system warranty, because an argument over air locks when refilling would be valid. CC does read this forum. Outside warranty, the re-instatement of the standard Duratec bypass looks like the way to go in my book.

The pump is a ford part, so I would assume its been well tested. I don't know if the source of the plastic fuel hose.

I agree, if you have a battery isolator the bracket holding the connector is removed.