I have fitted and refitted Caterham collectors many times, because both my 360R and my Sigma 150 had decat pipes, and therefore I swapped them at MOT time. I also carried the catalytic converter to track days as a way to reduce noise when needed.

I started by removing the sticker, and fitting the lambda sensor. When removing the protective cover from the lambda sensor, I was careful not to touch the sensor.

Next task is the modification of the spring clamp, because the clamp as supplied doesn’t sit flush on the collector or primary. To do this, I pulled the clamp apart and opened the angle slightly. This gives a few extra millimetres, which sometimes makes all the difference and that’s all that was needed.

I compress the springs with tie wraps. I start with two, but as the pressure builds they tend to slip around the spring, so adding another two tie wraps are usually required to get the spring fully compressed. I compress the spring until there are no gaps between the coils.

I find sliding the collector into the primaries is a juggling act, but since I still haven’t torqued the primaries to the engine there is plenty of wiggle room. A word of caution: make sure the primaries don’t touch the lower skin as the weight of the collector is applied! I spray a little bit of WD40 on the joints to make the insertion easier.

The spring clamps should just clear the mounting lugs on the collector and primaries. Once the clamp was in the correct location, I started cutting the tie wraps to release the tension, starting with the most difficult tie wrap to access.

With the collector fitted, I torqued the primaries to the 47Nm from the old manual.

The final step in the process is to secure the wiring of the lambda sensor, which didn’t got the way was I had planned. I had taken a photo of this at the Caterham showroom, from a factory build car. Unfortunately for me, due to the way my heat shield had been fitted, I would not be able to replicate this, unless I started removing sealing tape, which could result in damage to the heat shield itself. Therefore I needed a plan B.

My plan B was too use self-adhesive tie wrap bases instead, but normally the adhesive is poor in comparison to the double sided adhesive used for number plates for example. So I replaced the adhesive with that of number plate strength.

I realise this isn’t as strong or as durable as the riveted tie wrap bases, so I will have to include the inspection of them and the replacement as necessary in my service schedule. That said, they are only holding a short section of wire, which is also tie-wrapped to the chassis tube.

Tools Used

  • 22mm open ended spanner
  • 8mm 3/8” drive hex socket
  • 8mm 1/4” drive hex socket
  • 3/8” drive extensions
  • 1/4” drive extensions
  • 3/8” to 1/$ drive adapter
  • 3/8” drive ratchet
  • 3/8” drive torque wrench
  • Side cutters
  • Pliers
  • Knife