Caterham 420 Detailed Build Blog

An alternative to the Caterham 420R build manual


This blog documents my fourth Caterham and my second build. My first Caterham was a Vauxhall XE powered 6 Speed 40th Anniversary, then I had a few years break before purchasing a 2011 Sigma Ex Academy car which was converted back to Roadsport spec, with the 150 upgrade. My third Caterham was my first build, a 2016 360R. My 2016 360R kit wasn’t ordered by me, I purchased it with the front suspension bolted on, and that’s about it. So now I am building a 420R, with all the bits and colour I always wanted.

My first Caterham build took from May 2016 to October 2016, I only submitted my IVA paperwork in October and got a January IVA slot. I won’t drive my Caterhams on salt-covered roads, my first Caterham had suffered the after-effects of this, so I trailered the car to VOSA Gillingham. The initial inspection didn’t go exactly to plan, failing on a speedo that wouldn’t read over 30 mph and the steering rate gator catching the side skin when going from lock to lock. Both required simple fixes and I was given the time to attempt them during the test, however my speedo eventually only managed 50 mph before it died. I decided to waited for better weather before booking the retest in March 2017 and enjoy the thrill of driving without number plates.

Since this Caterham will be delivered in September (fingers crossed), and assuming I take the same length of time to build, I expect to be ready for IVA February 2020, again I will be waiting for the better weather so I plan a late March early April 2020 IVA.

I intend this blog to be a detailed build guide, which can be read in addition to the official build manual. But be warned, Caterham are continuously updating the specification of these cars, so your kit could differ from mine.

I am obsessive, I want to produce the best quality build I can achieve, I am also pragmatic, i.e I won’t get hung up on bending parts when the manual describes it, but I don’t like the “if in doubt grind it out” approach. I own metric and imperial tools and using the correct tool for the job is one of my obsessions.

I will also deviate from the build manual, especially the order of assembly prescribed in the “IKEA” style manual. I also already know some of my fixings will replaced because for quality reasons and personal preference. Be warned, deviation from the Caterham build manual must be done at the reader’s risk. I have read blogs where Caterham have restored the car to build manual spec at the builder’s cost during Post Build Check (PBC).

I really only have one day a week where I can spend time in the garage, so don’t expect fast progress.

This blog will cover the build from delivery day until registration. I will also cover any build bugs that have to be ironed out during the running in process.

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