MattB

I had the 2.0 Duratec engine in my MX5 rolling road tuned some years ago. The tuner said that using 99 octane wouldn't make a difference in a naturally aspirated engine, but he was surprised to find that he could add much more advance than he had on other engines, resulting in what was a better tune for me.

I carried a bottle of octane booster in the boot, but never used it. It's now in the boot of the 7. The MX5 did, however, have a knock sensor.

MattB

My sister saw this in Stoke Newington.  Apparently it's been there for months and hasn't moved. The MOT ran out last July and it doesn't appear to have been SORN'd.

Note the parking ticket.

MattB

I sent a query to Caterham Gatwick through the website and got a phone call within an hour. Apparently those wires are for an older speed sensor which is no longer fitted.

MattB

Instrument illumination is usually a red/white wire, so I don't think it's that.

I've seen a sound system in a 7 but I'm pretty sure they were never factory fitted (for or with).

What intrigues me is the fitted grommet and the relatively heavy duty female connector.

Looking on the internet it seems that black/purple wires are used from temperature switches to warning lights, and purple/black wires are used for horn to horn relay to horn push wires.

Still no idea what this connector is for ...

MattB

2021 420S

MattB

Jonathan

The rear brake light connectors (one for a green/purple wire, one for a black wire - two separate white connectors) are tied up to the side of the fuel tank, so this is definitely not a brake light connector.

The feed wire is black/purple (only just noticed that the purple is the tracer).

MattB

I have just found this connector cable tied to the chassis on the bulkhead behind the driver's seat.

I can't find a connector with purple/black and black wires on the wiring diagram.  The fitted grommet would indicate that it should have gone through either the bulkhead or the floor.

Does anyone know what this is meant to supply?

MattB

I followed Dave's lead and bought a pair of 210mm blades from pgil3454 on eBay.  Saved a third on what they would have cost me from Melvyn Rutter.

He has 200mm, 210mm and 220mm lengths available, but the pivot isn't in the same place on all of them.  Judging from the photos the 200mm has 108mm above and 92mm below, the 210mm has 118mm above and 92mm below, and the 220mm has 113mm above and 107mm below.

The 210mm blades are pretty much a perfect match for the ones CC fitted to my SV.

Photo attached.

They are stainless, so I used a rattle can to make mine black. As Gavin says in his article I had to bend over the tabs on the socket.

Just need some rain to see how well they work ...

MattB

Back in 2020 CC recommended that I have them flat floor my 7 during the first service (the one where you pay them to find out all the bits they hadn't assembled properly the first time around).

I told them I weighed 82kg fully booted and spurred. The invoice showed they used 82kg as my weight. The alignment sheet, however, showed that for some reason they actually used 89kg as my weight. The service manager had no explanation for the discrepancy.

The car was a completely different animal on the drive home. Far more planted, turned in much better, generally much more confidence inspiring. For me it was yet another indication of just how little care or effort CC gave to my car when they built it.

How many people are driving around in new 7s but have decided that they don't need to get their cars flat floored and so have no idea just how wonderful their cars can be to drive?

MattB

The blades on my 2021 SV are 213mm long.

According to the details on the Melvyn Rutter MogParts site the improved blades for the Plus Six and Plus Four are 210mm long.

So, if the pivot is in the same place, they should be pretty much a perfect swap for me.

Will be ordering some ...

MattB

The fusebox in #9 doesn't look like any I've seen in a 7 before, and it's very different to the one in my 2021 420.

For starters it appears to be in the engine bay?

MattB

ECR - I'll probably give that a go, thanks.

7 Wonders - I wouldn't be without my heater or heated seats. I drive my 7, roof off, throughout the year...

MattB

My heater valve appears to be leaking from where the upper 'T' is pressed into the valve body.

Has anyone else experienced this?

If there's an easy fix I'd rather do that than deal with it as a warranty issue.

MattB

Worth noting that Toyo only approve fitting the 205/60 tyre on wheels between 5.5" and 7.5" wide.

MattB

The knock sensor on a Duratec is usually on the left side of the block directly under no.2 intake runner.

It's an empty space with just the threaded hole for the securing bolt on my 420 (note - photo's upside down).

MattB

When my Mk3 MX-5 (2l Duratec with VVT) was being tuned on a rolling road I told the tuner that it had always been run on V-Power. He said that it wouldn't make any difference. A few hours later he expressed his surprise at how much ignition advance he'd been able to programme in safely, getting higher bhp readings than he'd ever managed before on cars that ran 'normal' fuel.

It does make a difference in a NA engine, but you need to reprogramme the ecu to see that difference.

MattB

Just noticed that the upper coolant hose on my 420 was rubbing against the sharp edge of the intake plenum, and was happily working its way towards a coolant leak.

I added a second tie wrap to the hose to keep it away from the plenum, and filed the edge of the plenum to a smooth curve in case the hose does move.

This is the second build fault that I've found trying to cut through the top hose (the car was built by CC at the end of 2021), and it's even more annoying as the car was with CC a couple of months ago for a radiator replacement.

If you have a new(ish) build from CC I'd recommend having a good look at the top hose ....

MattB

My Dec 2021 build 420 runs between 85 and 100 indicated, with the fan coming on around 103 indicated.

MattB

The mirrors on my Jan 2022 420 were rubbish.  The spring that held the arm to the base was different to the one shown on the Caterham parts webpage, and was so weak that the mirror was hanging loose after a few weeks.

I had to cut a 1" hole in the front of the mirror to reassemble things after loosening the mirror screw too far. A rubber blanking plug filled the hole neatly.

At this point I was fed up with the damn things. I now have a set of Spa mirrors on Eccles mounts - infinitely better.

MattB

Thanks Jonathan - you are the Turnimator ....

MattB

The fit looked good, the bobbins didn't appear stressed or twisted, and the hoses didn't look to be pulling/pushing on the radiator.

My 9 month old Caterham built 420 has just had its radiator replaced by CC under warranty.  I'd been monitoring it closely, having read this and other similar threads, and thought I'd got away with it, but it started leaking from both sides at just under 6000 miles.

CC asked no questions once I said it was a radiator problem, and just booked it into their first available workshop slot.

It appeared that the leaks were where the matrix tubes entered the side tanks, so I'm wondering if the mounting arrangement is too tight horizontally, leading to the tubes expanding into the immovable side tanks when hot and breaking their seal. Perhaps slackening off the bolts and elongating the bracket holes on one side and allowing the radiator to expand horizontally as a whole might lessen the chance of another leak?

MattB

The coil cover doesn't stop water from the bonnet louvres getting into the plug wells.

MattB

Cars with a quick release steering wheel don't have a steering lock, so no need for shear bolts.

MattB