I suppose it was inevitable that I would eventually upgrade the coil cover to a carbon coil cover, mainly because it was the only bit of Caterham carbon that wasn’t fitted to my car.

The most important thing to consider when fitting the 420R coil cover, be it a carbon one, painted one or standard unit is make sure the coil cover doesn’t contact the bonnet. If it does it won’t look good for very long. You can see my technique for checking the gap between the bonnet and the coil cover during my Bonnet fit post.

You can see from the photos, one of the trick to lower the coil cover and increase the gap between the bonnet and the coil cover is to rearrange the coil wiring and use a few tie wraps to secure the connectors and wiring within the coil cover.

The standard coil cover is secured with two T30 torx screws. which need to be removed to change the coil cover.

Next the rubber bung is swapped from the original coil cover onto the carbon coil cover. The cut grommet is glued onto the original coil cover, so a replacement grommet was cut and glued to the carbon coil cover. I used the same glue I used for the Chassis (Side Panel) IVA Trim. I used a socket to hold the cut grommet in place while the glue set.

Fitting the carbon coil cover again with the T30 torx screws was simple enough, but there is a fibre washer above and below the coil cover, and the fibre washer below can tend to slip off before the screw is fitted. On my fibre washers there was some evidence of a small dab of super glue, which Caterham must have used to stop the lower fibre washer from moving during coil cover fitting. Consider using this trick if you have difficulty refitting these washers. Also a dab of Loctite 243 on the screws will stop them vibrating free.

I decided to fit a rear wing decal to finish the look. The procedure is the same as fitting the Decals and Nose Badge.

Don’t forget to check the gap with the bonnet again with the new coil cover.

Tool Used

  • T30 Torx hex adapter
  • 8mm ratchet ring spanner
  • Socket (19mm 3/8″ drive long reach)
  • Ruler