Caterham 420R Build

Build Session 32 : LHS Indicators, Swap Wing Stays, Repeater Wiring

Another short day I’m afraid, just an hour today.

LHS Indicators

After all the “mucking about” yesterday with the LHS indicators not working I thought I’d give them another go this morning. I took the bulbs out from the  two indicator pods and was determined I’d go through the whole thing methodically.

Front RHS indicator pod

The first obvious test (that I’d already done yesterday) was to try the RHS bulb in the LHS pod… it worked! Hmm!

I then put the original LHS bulb back in the LHS pod and it worked! Hmm!

From that point on I couldn’t get the LHS indicators to fail. We’ll see how this holds up over time. I’ve no idea what the problem was, but I suspect a poor electrical connection in the bulb holder. Hmm… I don’t like mysteries they come back to haunt you.

[Note from the future: even after lots more testing, PBC and IVA… the indicators have been fine. We’ll see if they hold up to real-world use but for the moment no problems]

Wing Stay Swap – Grr!

Ok, so onto something more productive, front wings.

I’d ordered carbon fibre front wings for the car, mostly on aesthetic grounds but also due them being so much lighter than fibre glass versions and this would keep unsprung-mass down – that’s what I’m telling myself anyway!

The wings had perched on top of the wing stays at various points in the build – mainly to keep them out of the way. They’d picked up a couple of scratches in the process but these things are not going to stay pristine for very long once on the car, so I’m not bothered about those cosmetics so much. I probably should have covered these wings in masking tape when they arrived – and I’d recommend anyone receiving a new kit to do exactly that.

Anyway, seeing as the wings had been on the wing stays so many times I would have thought I’d have noticed that each of the wing stays were on the wrong side of the car – and therefore pointing backwards. It was only when I put the wings onto them loosely to look at how they would be attached that I realised the stays wouldn’t allow the wings to sit anywhere close to where they should do… you have to have the front leading edge of the wing vertically forwards of the wheel rim (not the tyre) to pass IVA.

I thought I had previously spent a minute or two getting the wing stays on the right way round when I built the front suspension. I distinctly remember thinking that they could only go on the way I had put them on and that I must therefore be right… wrong!

This wing stay should be on the other side – this is the WRONG orientation

And now with them swapped sides…

Now with the wing stays swapped to the right side – CORRECT orientation

That was a 45 minute job that I needn’t have done. However, looking back at the manual, it’s not at all obvious from the instructions which way you’re supposed to do this. Now I know more about Caterhams, it makes sense to do it the right way, but it didn’t when I was starting out and working on the suspension at the beginning of the build.

Front Indicator Repeaters

Another waste of time job…

Now I had the wing stays on I decided to wire the front indicator repeaters through the wing stays. Sounded like a good idea, except I forgot I had to also wire them through the wings themselves… as there’s no way to feed the repeater through the hole in the wing from the inside out. You have to feed the wires through the wing from the outside of the wing and then down the wing stay – bugger! Hey-ho all part of the fun.

Anyway it was a good exercise in figuring out how the repeater wiring, grommets and heat shrink sleeving all went together.

I used some tweezers to extract a pull cord (some wire) through the stay and then to pull the green signal wire through…

Tweezers to pull wire from inside the wing stay – there’s a better way of doing this

And so it all looked like this in the end…

Repeater signal wire threaded through wing stay… wot no wing, wot no extended earth lead!@!

It was at this point that I decided I would definitely extend the repeater earth wire to terminate in the engine bay. The manual tells you to terminate the earth at the top of the wing stay – which is why the earth lead is so short and terminates in a ring connection. I’d intended to do this but this wiring exercise today definitely showed there was enough room to get all the wires and heat-shrink through. That coupled with the fact that I didn’t fancy the earth wire being attached to a very wet and grubby wing underside. Mind made up – extend repeater earth wires…. another time.

That was it for today. Progress on… the indicators working, wing stays each on the right side… and made progress on the thinking through how the repeater wiring would work. All of which today I need not necessarily have needed to do if things had gone differently! What fun!

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