ChrisC

2017 420R with either have a 6 speed or the 5 speed Mazda. It would be possible to convert to a Type 9 from a Mazda, but I suspect by the time you factor all the bits needed from a bellhousing, propshaft, gearstick and mounting brackets you might be into RBTB's money. If you are talking about air filters and decat pipes, then power increase is going to modest if at all, but I suspect noise would increase a fair bit. Why not look at the K&N panel filter that fits into the air box (from the 310R). I believe a decat 420R likes flame a bit, which if true will be reason enough for me to fit mine. I would be looking at a trip to Track N Road, and getting the stock map converted to a custom map for your car, they have the Caterham codes / software, so they are able to alter the stock locked ECU.

There was one breakdown company that advertised "No matter where, No matter what", and when push came to shove, it did matter where and it did matter what, as I found out to my cost. Always read the small print with breakdown cover, and make sure it covers what you want.

Nice :-)

I personally believe the "sub loom" between the sensor and the chassis loom has a lot to be desired in this area. It seems like the sensor (with sub loom) and gauge are supplied by Caerbont to Caterham. Under the PVC cover of the sub loom is a diode and a resistor soldered to the bare wires with little in the way of weather protection, which is in contrast to Caterhams approach of using waterproof connections (Econoseals). There has been a post on here showing how corroded this sub loom gets, and I suspect this has more to do with the accuracy/reliability than the sensor itself. For reference here is the post from "egnshane" https://www.lotus7.club/forum/techtalk/oil-pressure-360r

Does your 620 have a different colour chassis? Obviously Caterham took painting in house and stopped using TSK. I suspect based on age both of your cars where painted by Caterham not TSK. But even if that section of the frame wasn't panted it should be the powder coat colour, normally black obviously. Your 620 chassis almost looks silver, from the photo.

Are the aluminum fuel tanks ok? Have they been sealed or are going to get corrosion from the hygroscopic effects of ethanol?

With my 420R kit one of the seat belt boxes had four plastic nut covers and two rubber bungs in a bag tapped to it. It looks like the two rubber bungs are for the inertia reel belt mounting holes. Also found it https://caterhamparts.co.uk/seatbelts-harnesses/783-grommet-seatbelt-blanking-a-clutch-fork.html

Dunsford handling day is a track testing day for road legal vehicles. I just googled max car age, 10 years apparently, they will cover 25 year old cars if you get personal cover not car cover.

From The AA Terms and Conditions. (Sept 2019) So that's track test days for road-legal vehicles covered. Ironically my biggest (to date) Caterham failures have not been track related.

The real question is what plates does your diff have, I believe there was a time when Carbon plates where tried, and these tend to wear quickly. https://www.lotus7.club/forum/techtalk/270r-lsd-problem

Sounds like it was already filled with Motul Gear Competition SAE75W140, The Comma stuff they used before 2017(ish) wasn't blue.

You just can't compare that diff in a BMW to the Caterham adaptation. The back plate with the drain plug isn't a BMW part, so oil quantity, and fill procedures are going to be a different process. What you need to consider is your Caterham BMW LSD diff is a reassembled differential by Caterham's suppliers, after the BMW casting has been machined to fit, and the internals have been changed to the LSD, so the quality of the end product is dependent on the person doing that work. It's entirely possible the seals where damaged (and not spotted) during that process. As for the official BMW diff fill quantity it depends on spec, but a 168LW diff has .75ltr and 188LW is .8ltr, so Caterham are more inline with BMW now.

The recommendations for the manual of 0.8 ltr, if you fill with that amount it won't dribble out.

There is no drain hole, you will have to suck the oil out.

Fill hole is blue, if you follow the manuals recommended 0.8ltr fill it won't overflow.

Have you still got the Caterham part label on the propshaft? Its worth a look, even if faded over time.

The back cover and cage has changed design several times, so it's just a different version. Problem is finding the best approch for that version of the BMW diff. If you have an LSD or clutch style diff (Haldex) in a tintop it will have an oil change schedule.

14mm hex socket and a breaker bar will loosen it, There is plenty of clearance if your car isn't supported by the De Dion tube but by the chassis on axle stands. Maybe this helps with pictures of the tools and how to access the fill plug. My 14mm hex socket is from a Laser set. https://caterham420detailedbuildblog.co.uk/2020/02/06/fill-the-diff/ To drain the diff I used a large Sealy oil suction syringe.

Just checked my kits washer bottle and the fitting is 5mm at the narrowest point.

My guess is Steve wont have the voltage but the "throttle site" and how he sets it. Easymap shows a lot of information, the secret is to concentrate on whats relevant and add more readouts as you go. So in this example, throttle pot voltage and throttle site may be a good starting. Good luck

Ok, so important information there. Even the 150 had a MAP sensor that's open to the air, it still affects the map, just no to the same extent, and you are right it's for driving to the Alps :-), but unplug it and the car will run like a pig (on a stock 150). All bets are off if Steve G has worked his magic on your car, my information is based on stock setups. Given the above information, you need to restore your TPS to the value it was when Steve worked on it. That's the problem, and reason CC don't use TPS based maps, the map becomes dependent on the TPS value, and these are not all consistent. The ECU isn't capable to learning, so setting up becomes the important part.The resetting of the ECU is just something you should do every time any change is made, be that mechanical or electrical, so the ECU when starting has the base values, this can only be done by pulling to power (easy with a battery isolator). BUT There is one thing that springs to mind, was it raining on the way to the cambelt change? I have heard from the specialist that did my 150 conversion that the open to the air MAP sensor can suffer from direct water strikes. He recommended a small hose to make a U bend to prevent this, still open to the air, just not upwards. Since it's such a small expense I have done this to all the 150 club members that have come to me for a tune up. Never seen it myself so I only have that on hear say.

The 140 uses MAP (manifold absolute pressure) to control the ignition and fueling, and the TPS is a guide to inform the decision. This didn't work on the 150, although it was tried, hence the switch to TPS lead strategy. I suspect the TPS position won't be the same as the 150. Obviously the best thing to do is get it on Easymap and see whats going on, but short of that a few things you might like to try. If you don't have a battery isolator try disconnecting the battery for 10 seconds and reconnecting it, the ECU is always powered so this is just resetting any learned behavior, you need to do that each time an adjustment (like the throttle stop) is made. Manifold pressure leak, have you got a split in the small rubber air hose to the MAP sensor, or any of the bungs on the plastic plenum. Finally lambda sensor problem, but the symptoms of this are well documented.

For reference http://www.fordopedia.org/parts-catalog/sierra-mk1/E3.30 Nipple Ford part number is 1486865 or 71EB-2208-BA https://www.ebay.co.uk/itm/Genuine-Ford-Brake-Caliper-Bleed-Screw-1486865/272376563331?epid=1309768519

I use POR15 chassis top coat, I spay a little into a cup cake liner and touch up from that.

Both the rear brake hose and the clutch hose have to be covered, but the front brake hoses can remain uncovered. I can't tell you when, or why or by who, but it appears that once a precedent has been set that’s how they then need to be presented. I have my opinion on why cars are failing three times and I have experiences which have formed that opinion, but it’s not for a public forum. Personally, I have been present at two IVA tests, and both times the tester wanted to pass the car and did everything within their power do so within the allocated time.