This post isn’t really about fitting the bonnet; after all, every time you want to you work on the engine the bonnet will be removed. It is more about checking the clearance.

When fitting the nose foam, I start with one end near the Dzus fastener, holding the foam straight while pealing the backing paper off. I prefer to have the foam close to the edge of the bonnet, so I went for 5mm from the recess.

The foam along the edge of the bonnet can either be stuck on the top of the side skins, or the bottom of the bonnet. I prefer the bottom of the bonnet.

The foam at the back edge of my bonnet was already applied to the chassis by Caterham at the factory.

Sticking foam to the nose cone and bonnet isn’t a permanent fixture. If you’re not happy with the result, just order some more foam and redo the bits you need to.

The coil cover has a tendency to touch the bonnet on the Duratec engine cars. It’s not just a case of tightening the coil cover screws. I removed the coil cover and adjusted / relocated the location of the a few engine loom connectors and applied a few tie wraps to get the coil cover lower. I also noticed that the coil cover was touching one of the cam cover nuts at the rear of the engine, so I made a small adjustment with a half-round file.

One of the screws for my 360R coil cover disappeared on the way back from the IVA test, I assume it happened because of vibration, so I started using Loctite 243 when fitting the coil cover; I have not lost a coil cover screw since.

You can see how close the coil cover is to the mounting bracket for the fuel rail. I felt this was close enough to test the coil cover bonnet gap.

I can’t take credit for this trick, I saw in on the Kindig Customs TV show. To measure the gap between the bonnet and the coil cover, I used aluminium foil, knowing it will crush when the bonnet is fitted if there is a gap problem. Thankfully, my coil cover has plenty of gap with the bonnet.

I especially recommend checking the bonnet gap if you have a painted or carbon fibre coil cover.

Bonnet fitted

I prefer to fit the bonnet with the aid of a helper, because fitting the bonnet around the air box seal its tricky single handedly.

Tools Used

  • Torx T30 hex bit
  • Ratchet ring spanner (for Torx bit)
  • Side cutters
  • Scissors
  • 1/2 Round file