Build A Caterham 420R in 30 Minutes – YouTube Video

On July 11th 2020, I uploaded a bit of a longer video to YouTube documenting the build of my 420R from nearly 3 years previously.

I’d always planned to do this video, but for the usual many reasons it only got a few hours here and a few hours there since finishing the build in December 2017. But I had a week off work and with the weather being a bit crap I decided to give it a final push over the line. I have no idea how many hours it took to edit the video but its probably well over 50 and might be closer to 100… bonkers, I know! And that’s obviously ignoring the 160 hours of time spent building the car to create the time-lapse itself. It too me two days just to add captions to it!

The video is a bit rough in places, but I wanted to get something out as I hope its a useful addition to my (and others) blog. My problem with the video over the past 2 years has been that I really wanted/needed to make it twice as long to be able to say all I wanted to about the build, but even now at 33minutes there will be very few people that watch it, and at over an hour I could pretty much guarantee that nobody would.

So, the video is what it is. If I was doing this video again then I’d make a better job of the audio. Both the pieces to camera and the voice over of the build itself could really do with less noise on the audio and a compressor applied to lift some of the quiet phrases. The voice over for sessions 1 to 15 had the microphone gain set too high and was hitting the limiter and I should really have re-recorded the voice over again once I’d got to the final wording I wanted to use – the result that ended up in the video was something like 600 sections of audio cut and spliced together and took me weeks to edit down to something that sounds vaguely ok to listen to. There’s nearly 8000 words spoken in the video – no small undertaking!

And if I was setting up the GoPros at the start of the build again, then I’d make sure I took a bit more time to get a good close-up of what I was doing at each stage of the build. Certainly 3 GoPros made for a better video I think. One would not have worked for me, two would have been a minimum and four would have taken forever to edit.

I don’t quite remember now, but I think I set the GoPros to record the time-lapse with 30s intervals. I used 3 GoPro Hero 6 Blacks for the main time-lapse. They’re the first GoPros (I think) to have in-built support for time-lapse. Prior to the Hero 6 Black you had to get the cameras to save stills and then stitch them back together to make a movie afterwards.

The Video and Audio Gear

In the garage I had 3 GoPro Here Black 6’s. They were set to time-lapse at 30s intervals. Each was set to run at the start of a session and stopped at the end. I used GoPro flexible gooseneck mounts to attach them around the garage and plugged them into USB power to keep them going for up to the whole day. Each had a 64GB Sandisk memory card in them.

I also used my iPhone to take over 800 photos that became the blog, but also used it to take some video at times – the side on shot of the engine starting up is shot on iPhone for instance.

For the “to camera” section I used a Canon EOS RP and 15-28mm F2.8 lens to get the blurred background.

When recording audio I use a Zoom F6 in 32 bit mode and then either a Rode Wireless Go and cavalier microphone or a Rode NTG, also into the Zoom F6.


The video was edited in Final Cut Pro X on a selection of Macs and the whole project was about 2TB of footage and proxy media… the proxies were needed because I had to speed the video up in two stages. With hind-sight I would have created sped up versions of the GoPro footage, exported it and re-imported it again to save the Proxy space at 4k. All the video was shot in 4k to give me room to crop and zoom if I needed it. I also created multi-cam clips in FCP to be able to cut from one camera to another more easily. However, that didn’t always work and there are a couple of sections of the video that repeat but from different camera angles. If I were doing it again, then I’d pay a lot more attention to the time/date settings on the cameras to help getting the clips synchronised – and probably used time-code generators… that sounds overkill but it would have saved so much time in the edit.

Like many YouTube videos, the edit got pretty complicated with all the graphics, overlays and animations. Here’s just 2 minutes of the edit timeline for the intro…

View of Intro section of the video in Final Cut Pro X

Anyway, as I say… it is what it is. It won’t be winning any awards, that’s for sure.

Below is the text from the YouTube description… note: when you’re in YouTube now, you can click on chapter markers to jump you to wherever you want to go in the video… my favorite bit is the trip to the IVA at the end of the video when I’m leaning out of the car to see through the rain after the wiper fuse blew as I left the house! πŸ™‚

I hope its a useful resource and of course I’d appreciate feedback, especially if I’ve made any glaring mistakes.

And here’s the text from the YouTube description that includes the chapter minute:second timings,, but you can find that on YouTube too!

YouTube Description Text…

Almost 3 years after turning on the first GoPro to film our Caterham 420R Kit Car build, I finally got around to creating this video…

This video is a recap of the major points of our build and is in no way representative of everyone’s experience – every Caterham and every build is different!

It has taken many many hours of editing to get this video into the shape you see here. The audio is a bit janky in places and there are too many jump cuts in the pieces of me to camera… but after 3 years I decided I just had to get something published.

Hopefully it’s of some use to anyone building, or looking to build, a Caterham. 

[ Bonus points for anyone who can count the number of “in the ends”, “at the end of the days” and “measure twice, cut onces” πŸ™‚ ]

Finally, yes.. I know sessions 24 and 32 a missing – I forgot to roll the cameras for some reason. Here’s the break down minutes:seconds of each section of the video…

  • 00:00 Intro
  • 03:20 Arrival
  • 04:20 Session 1: IVA Trim and Steering Rack
  • 04:57 Session 2: Body Protection & Gearbox, Bellhousing, Engine
  • 05:31 Session 3: Harness Tapping *
  • 05:41 Session 4: Front Suspension 
  • 05:59 Session 5: Front Suspension & Headlights
  • 06:35 Session 6: Headlights & Front Suspension
  • 07:44 Session 7: Uprights
  • 08:13 Session 8: Brake Pipes, Front ARB & Dinitrol
  • 08:33 Session 9: Horns and Final Front ARB Fit
  • 08:57 Session 10: Engine Mounts, L-Hose & Hoist Extensions
  • 09:35 Session 11: Engine In
  • 10:53 Session 12: Attempted Gearbox Shift & Electrics
  • 11:59 Session 13: Exhaust Headers, Cat & Lambda Probe
  • 12:49 Session 14: Steering Column & Oil Tank
  • 13:43 Session 15: Odds & Ends, Radiator & Heater Unit
  • 14:17 Session 16: Roll Over Bar, Engine Plumbing & Bonnet Test
  • 14:48 Session 17: Engine Plumbing
  • 15:43 Session 18: Prop Shaft & Differential
  • 16:22 Session 19: Handbrake Cable, Diff Oil & De-dion Tube
  • 17:16 Session 20: Handbrake, De-dion, Rear ARB & Radius Arms
  • 18:03 Session 21: A-Frame, Rear Hubs, Brake Pipes & Wheels
  • 18:55 Session 22: Knee Trim & Carpets
  • 20:13 Session 23: Carpets & Seats
  • 20:43 Session 25: Engine Stqrt
  • 22:01 Session 26: Water Bleeding
  • 22:11 Session 27:  More Water Bleeding
  • 22:39 Session 28: Boot Floor, Fuel Filler & Carpets
  • 23:39 Session 29: Fuel Filler, Torque Rear & Rear Wings
  • 25:11 Session 30: Washer Bottle
  • 25:42 Session 31: Rear Brake Hose, Rear Lights & Indicators
  • 25:58 Session 33: Front Wings, Lights, Handbrake
  • 26:59 Session 34: Brake and Clutch Fill & Front Wings
  • 27:54 Session 35: Front Wings, Handbrake Cable & Tidy-ups
  • 28:26 Session 36: Repeaters, IVA Mirrors, Wipers and Rear Hubs
  • 29:38 Session 37: Getting Ready for PBC
  • 30:44 Post Build Check
  • 31:25 Individual Vehicle Approval
  • 32:41 Conclusion

Some People Must Be Watching – Site Stats 60k Views

As we approach 3 years since out kit arrived I thought it would be interesting to share some stats on this website.

I created the site for two reasons.

Firstly, it was to give something back. I’d looked at many build blogs and learnt so much from them. And I wanted to be able to give something back to “the community” by hopefully helping those coming after me.

Secondly, I wanted to document my build. The added nudge of the blog, every time I stepped into the garage, got me taking more photos and documenting what I was doing. I still have a chuckle whenever I read it back through again.

So, in part to show people that blogging a build is not a worthless exercise, and that people building after you do actually look at what you’ve written, here’s a statistics print screen from WordPress on where we’ve got to.


So, as of today (July 20th 2020) we’ve had 60,000 page views. Here’s a view from the WordPress Monster Insights statistics page for the past 30 days…

Softbits for Sevens Boot Cover & G-clamp Hack

Well, one thing led to another!

So… for a while now, like many, I’d ditched the Caterham full-hood and have been using the Softbits for Sevens Half Hood (

The half-hood is great, perhaps not as water tight when it’s tipping down and you’re on the motorway, but it only lets a small amount of water in and has the benefit of not making the windscreen fog up with all the moisture in the cabin. It’s also way easier to fit and much smaller to store – a totally worth it upgrade and one it seems just about every Seven owner goes with.

Anyway, that meant that the hood sticks I had installed on the car for the full wet weather hood were redundant and clattered around a bit over bumps.

And so removing the hood sticks cuts down on the clutter but means that the boot cover doesn’t fit correctly and is baggy on the top of the boot.

Here’s the old boot cover looking rather baggy:

Old boot cover looking rather baggy

Which leads us to Softbits for Sevens boot cover replacement (

Now, I’d had the new boot cover for over a year and not got around to fitting it. The winter and then pandemic meant I’d not been out in the car very much. And if it’s stuck in the garage then its not so easy to manoeuvre around in there.

So, with the weather on my side for a couple of days I decided to have a go at the boot cover. Read on to find out what hacky-bodge of a tool I came up with to make the whole thing work for me.

The Theory

The theory goes… you have to:

  1. Remove the old boot cover
  2. Extract the aluminium stiffening bar from the old cover
  3. Cut a slot in the new cover to insert the old stiffening bar into
  4. Mark positions for holes along bulk-head edge of the new cover to match holes in the bulk-head
  5. Stamp out the holes you just marked that line up with bulk-head holes
  6. Fit new cover to bulk-head
  7. Punch a hole in the new cover for each studΒ 
  8. Attach new stud
  9. Repeat steps 7 and 8 for each of the studs (it was 13 studs on my 2017 car)

In the Bag

When you order the boot cover from SBFS you get:

  • The cover itself,
  • 16 fixing studs (caps and buttons),
  • A cutter for cutting holes in the hood fabric (for the studs to fit through) and
  • A “doming” tool to mould the top of the deformable button shaft and so seal the button and cap together, with the hood fabric between them of course!

Here’s the diagram of the sandwich you have to make (from the SBFS website):

Press stud sandwich

From the top of that diagram we have:

  • Doming tool
  • Popper cap
  • Boot cover fabric
  • Button
  • Button Receiver (showing where the button goes with the dotted line)

The thing I’ve called the button-receiver is a blue concave dish which is used to give a stable base for the button to go into when you’re whacking it, something to stop the button being deformed/dented/dinged as you smash the crap out of it and to spread the load a bit too I guess.

Tricks of the Trade

Tristan from SBFS also gave me the following tips:

  • Leave the new cover in the sun for an hour or so Β (if such an orb exists in your sky) to soften the material, make it more pliable and also so it will shrink slightly once fitted and cooled.
  • Do the bulk-head first
  • Then start with the centre rear stud and work outwards and towards the front.
  • Also got this (paraphrased) from somewhere on the SBFS website: make sure there’s no slack in the press studs once fitted – the cap should not “rock” on the button shaft and be loose. The button and cap should squeeze the hood material and make a tight fixing.

With all that out of the way, here’s what I did:

Remove the Old Boot Cover

We have the 4-point harnesses on our car, so they need to be removed along with the four poppers that can be used to secure a tonneau, if you have one. The tonneau poppers have philips/posi heads and are easy to remove. The harnesses are less easy to remove, especially with the track-day roll-over-bar, there’s not much room to get the outer bolts out under the roll-over-bar. You obviously have to make sure the harness bolts are torqued up correctly when re-installing them – They’re the only thing keeping you and the car together if you ever have a significant deceleration event (or crump/off as we call it!).

Once those are removed the boot cover comes away from the car.

Extract the old Aluminium Stiffening Bar

There’s already a slit in the old cover that was used to insert the stiffening rod, so the stiffening bar slides straight out of what is a wide hem in the bulk-head (front) side of the cover. My stiffening barΒ was really banged up and I took some time to straighten it as much as I could before inserting it into the new hood.

Cut Slot in New Cover

The new boot cover didn’t come with any way of fitting the stiffening bar. So I put a slit in the off-side side of the new cover. Obviously the slit needs to be on the underneath of the cover. There was also an arrow marked on the stiffening bar, showing what direction it should be inserted into the boot cover hem.

At this point I also cut the length of the stiffening bar. The new cover was slightly narrower than the old cover and the stiffening bar would have been too long. I cut about 10mm off each end with some tin-snips – that may have been a little bit too much than I could have got away with, but I wanted a bit of slack at the ends of the hem so I wasn’t forcing the stiffening bar into the new cover hem.

Mark Bulk-head Hole Positions

You now need to transfer the position of the holes in the bulk-head onto the new cover, ready to cut holes for the harness bolts and tonneau poppers.

The way I did this was to lay the new cover over the bulk-head so it was central between the roll-over bar uprights. Then I marked the new cover, with a green paint marker pen, where the harness and popper holes were – being very careful to be mm accurate.

That gave me the lateral positions of where the holes should be.

I then measured (with the stiffening rod slotted into the boot cover) the centre line of the stiffening rod, which was 11mm from the edge of the cover. Β I could then measure 11mm from the edge of the boot cover to line up with each of the dots I’d marked laterally.

Marking the rear of the boot cover to match holes in bulk-head

Cut Bulk-head Holes in New Cover

Before going any further, I offered the new cover up to the car bulk-head again… and again… and again… to check that I had everything marked out correctly and looking like I wasn’t going to have to buy a new cover after screwing things up! This was the point of no return.

Now I’ve got the positions where I need to cut holes where the bulk-head popper screws and the harness bolts will go.

For the popper screws I used a 4mm punch on my leather punch. SBFS give you a cutting tool in the boot cover kit, but my leather punch was a much more precise tool to use. And it also solved the same sort of problem that the g-clamp hack solved for when attaching the press studs (see later in this post).

Leather hole punch

For the harness bolts I used at 12mm hole punch

Fit New Cover to Bulk-head

Now it was just a case of refitting the new cover by fixing the poppers and harnesses back into place.

Fitting the Studs

Now comes the tricky bit.

With the new boot cover attached to the bulk-head you have a flapping boot cover that now needs all the studs attaching.Β 

However, the simple “doming” tool that comes with the boot cover kit, seems to be a little light weight for the job.

Doming tool

The idea is that:

  • You put a button (that has a deformable shaft on it) through a hole you make in the cover fabric,
  • A popper cap goes on the button shaft, sandwiching the boot cover fabric
  • You put the blue button receiver on the back of the button and place it on something substantial to take a few knocks
  • Line up the doming tool on the button shaft
  • Whack the hell out of the doming tool to flatten the button shaft and stop the popper cap from coming off again
From left to right: button receiver, button, popper cap

All of that was a problem for me.

With the boot cover attached to the bulk-head there’s no easy way of finding anything substantial to place the blue button receiver on and then to do the whacking needed to dome the deformable button shaft.

One option would have been to mark up where all the 13 press studs needed to go, then take the boot cover back off the car (undoing the harnesses and poppers again). With the cover off the car I could use something solid behind the button receiver to put enough energy into the doming tool to make the domes (i.e a chuffing big lump hammer). Β But that didn’t sound like a good idea. It was a lengthy job to take the cover off, for sure, but I’m sure that as I stretched the hood applying the poppers in turn, the positioning of the next popper to be inserted would change… and lead to slack in the cover once all the poppers were done and then the cover refitted. The only sure way to do it with this taking-the-cover-off-again method would have been to take the cover off and on again between each stud – that would take forever and not be good for the longevity of the harness and popper fixings. So, I needed a different approach.

With the boot cover attached still, I tried putting some small “slabs” of marble I had lying around the garden onto the boot cover, under the button receiver. The slabs gave me something sturdy to hit against, but that was going to mark the cover and there was nowhere near enough “mass” in the slabs to allow enough reliable whacking.

SBFS do provide a tool service where you can pay a deposit and then Β£20 for the hire of a proper tool to fit the studs. But I hadn’t planned to do this job and so didn’t have time to arrange for the tool to be sent out and you can only have it for 7 days anyway. You also have to be a member, which I am of course.

The proper tool you can hire looks like this, from SBFS website:

You can hire this pro-tool from SBFS

So… I pondered the problem over night.

I came up with a few hair brained schemes to try and squeeze a dome onto the button shaft but nothing really grabbed me as being totally fool proof ( or at least “this fool” proof!)

I thought of using adjustable pliers, mole-grips and even a tool I’d bought a long time ago that did plastic press studs (that showed promise but it wasn’t “person” (pronoun sensitive) enough for the job of the metal press studs needed for this project).

In the process of testing a few things out, I also managed to use up the three spare studs and caps I had over. I had 13 studs to fit, 16 came in the kit and I used 3 in my tests. I had no spares to get anything wrong now!

And then the brain wave hit me… I could hack a g-clamp!

The G-clamp Hack

I have a few g-clamps kicking around the garage, so I could sacrifice one for the cause.

My first idea was to use the g-clamp as it was.

But… the combination that needed to be compressed, to create a dome on the button shaft, was too unstable. It needed the button receiver, button, boot cover fabric, popper cap and doming tool all the be compressed together in the g-clamp and it all just crumpled under any pressure.

I needed to stabilise the whole assembly.

So, the next brain wave was to bore out the g-clamp threaded bar and insert the doming tool into it. That would keep the doming tool stable and apply pressure down though the shaft of the g-clamp thread and directly through the doming tool.

The g-clamp I selected was probably a little to small.

I didn’t want to waste one of my big g-clamps but I probably should have used a bigger one.

The problem was that I needed a 7mm bore in the g-clamp thread and that meant the remaining wall thickness around the bore I created was too thin. My g-clamp threaded shaft was 10mm diameter, leaving very little material after boring it out and taking into account the depth of the thread. More bored hole was showing through the bottom of the threads on one side!

Later on that bore wall would bend and eventually snapped after about 9 studs, meaning I had to re-bore the g-clamp threaded bar again. But that was ok… the g-clamp was sacrificed for the cause and as long as I could get all 13 studs completed then I was a happy camper.

The rest was pretty simple and would go like this:

  • Put some masking tape on the under side of the boot cover. I could probably have missed this out but it gave a good key for the chalk
  • Apply chalk to the bodywork popper
  • Pull the boot cover taught and press the masking tape against the chalked popper to leave a nice clear circle of chalk
  • Punch a 4mm hole through the boot cover in the centre of the chalk mark
  • Thread the button through the boot cover
  • Apply button receiver, button and popper-cap to the boot cover
  • Clamp and squeeze the crap out all this press-stud, g-clamp, doming tool sandwich

Here’s some pictures of all of that…

First bore of g-clamp thread


Full 7mm bore of g-clamp thread
Applying chalk to bodywork popper


Chalk mark transferred to masking tape


Cutting hole in the centre of the chalk circle for press-stud ( this one is slightly off-centre as I as adding dome more tension)
Using the g-clamp/doming-tool contraption
Press stud firmly attached to boot cover with no slack between them all


Broken contraption needed a re-bore
Softbits for Sevens Boot Cover installed


Hopefully, the dome I made on each stud will stand the test of time. The fixing looks really secure to me, but only time will tell if its secure enough. There will be a note here from “future John” if they don’t survive.

What would I do differently?

  1. Use a bigger g-clamp so the threaded shaft doesn’t deform under load. Mine had a 10mm thread diameter. I’d go a couple of mm larger than that if possible
  2. Bore the g-clamp thread to a couple of mm less than the doming tool length. That should keep the whole stack more stable.
  3. If I was doing this a lot (and couldn’t get the proper tool) then I’d put a split pin through the g-clamp thread and the doming tool to stop the doming tool from falling out of the bore made in the g-clamp thread.
  4. I had a bit of slack between the centre-most popper and the one’s directly on either side. I should have made the centre popper more taught and then applied more lateral Β tension when installing the two poppers on each side of it.

Lowflying Article – If Only Caterhams Could Talk, June/July 2020

I can’t really blame anyone for this article. Even when I was writing up the ECU work on this blog, I had it in my mind that I’d be able to do a Lowflying article at some time.

Then, when Michael Calvert asked members if they could write more articles for the magazine ( because there was a bit of a drought of articles due to the Coronovirus ) that was my cue.

However, like the ECU blog itself, writing this up for Lowflying took a lot longer than I thought it would, and because of its length, it had to get split across a couple of months of the magazine too.

I also found it really tricky to guess the interest from the Lowflying readers – too techie and nobody would read it, too simplistic and nobody would get any benefit. In the end I went with an approach where I left out detail but explained everything from basic principles. Clearly Lowflying readers are intelligent, but they may not all have an engineering or computer background.

The one area that I didn’t know whether it would stick or not, was the use of Russian dolls to explain how internet communications protocols get embedded inside each other and have to be unpacked to get to the real data you’re interested in. I think the metaphor worked but only time will tell if that is evident or not.

The full article can be read in Lowflying, June and July 2020.

LowFlying June 2020 – If Only Caterhams Could Talk
LowFlying July 2020 – If Only Caterhams Could Talk

* These articles were first published in the June and July 2020 editions of Lowflying, the magazine of the Lotus Seven Club for Caterham and Lotus 7 enthusiasts.

Driving Clifton Suspension Bridge – YouTube Video

This is a quicky… The weather was good and we were coming out of lockdown, so decided to get the car out for its first small run of the year.

The Video

I took a much longer run to get fuel and out from Bristol to Leigh Woods, Failand and then back into Bristol over the Cumberland Basin, but decided that I could make a quick video out of the run section of the run that went under and over the Clifton Suspension Bridge.

Here’s the video…

No Music Version

And, as is often the case, some people aren’t so keen on the music that I added. I always think the music makes the difference to a blat video but others don’t always agree. My problem is that with blat videos, especially on a Caterham where the camera is often in the wind stream, all you get is wind noise on the camera microphone. You can obviously add extra mics and/or additional recorders to get an authentic sound but in this particularly instance, I just chucked the GoPro on the car and went for a drive.

So, as a bonus clip for all you avid readers, here’s a version of the drive with just the on-board audio….

That clip is not searchable on YouTube, you have to know the link to be able to get there.

The Tech

I used a GoPro Max (360 degree camera) mounted to the top centre of the roll-over-bar to get the shot. I left the camera running for the whole 30 something minutes I was out in the car. That created about 30GB of footage to work with.

I then used GoPro’s Mac app to work through the footage and create four 1080p linear (not 360 degree) short clips. Each clip used key frames to set the camera view, selecting a linear shot from the whole 360 degree field of view as I went. I then exported each clip and created the final montage in Final Cut Pro.

Once in Final Cut Pro I created the graphics, used some tracking plugins to make the floating text effects work, and then added the music.

In total I spent about 20 hours to create 101 seconds of video! Much of that time was learning how to use GoPro’s software, how to use some new tracking plugins and making all the clips work in time with the music. I could probably make the same sort of video again in about 1/4 of the time.

Here’s what the 360 images look like before they’re processed…

GorPro Max shot of Clifton Suspension Bridge in a Caterham 420R

I hope you enjoyed that short post!