Weekend progress

 Again, more of an 'aide memoire' than any actual decent blog post. I've done most of the wiring loom, I just have four white/red power wires to join up together, and the same for four black ground wires. That gets rid of the spaghetti. Now the next part is to wire in the lights and dashboard.

There's a few blockers to that though. First off is that I seemed to have trimmed an entire lighting section out of the loom!! There should be a connector on the column multi switches that powers the lights, but now I've got to the end of this particular task I have no more connectors. I'll need to go back and see what I removed. It might be that I took each individual wire out in turn, then ended up with an empty connector that I stuffed in the 'spares' box. Once I find the connector I can wire it back in, 

I also need to print out the fuse and relay positioning, again I seem to have quite a few empty holes and I want to make sure I've not unwired something important. I also need to check the relays are still in the right place, for example I know the indicator flasher is wired in but it's missing two of the wires. I need to energise the flasher with some power and then see what comes out. The flasher is listed as;

• Black Ground.
• No connection
• Orange hazard light switch to Black Ground.
• Green Black to left hand lights (front/side/back and tell tale)
• Green Red to direction switch on column
• Green Yellow to direction switch on column
• Green White to right hand lights (front/side/back and tell tale)
• Black Red to fuse block

Looking at the existing wiring in the block, I can see;

NC          GR/RE      OR      BL

BL/RE    GR/YE      NC      NC

If the one below the black is the actual 'no connection' then the other two must be left and right. 

For the lights and dashboard it's all new, so it'll just be lengths of wire of the appropriate colour.

Ah yes, colours... I seem to have some wires that were attached to the loom, and attached to the engine, but neither end is actually attached anymore! I need to find;

• White/Blue. Apparently this is labelled as battery negative. 
• Green/Orange. This is most likely going to be the horn I think?
• White/Black. Off to the alternator for the battery?

None of them go to the ECU so I can rule that out straightaway. I'll have to double check the colours to see if they're actually what I have.

For other wires, I've got Blue Yellow to come from the fluid level sensor and the parking brake switch, when either of them close that puts a ground on the far end of the brake light tell tale to light the bulb. Black Blue for the coolant temp sensor, that'll go direct to the gauge with the other end being grounded.

I also have Yellow Red to come from the oil pressure sensor, again to the oil pressure gauge. 

I feel like it's all starting to come together now. I do have a lot of fused power feeds to go round the car, and there are so many ground points to put in. The grounds are fairly straightforward though, crimped ring connectors screwed to key points on the chassis. 

I'm going to try and get more done during the week, even if it's one or two wire colours a day I'd soon get them all done. Then it's a test, then bind up the wires and secure them ready for IVA. I have a route for the dashboard wires but I will need to make it IVA friendly, there's a sharp 180 degree bend that goes round an aluminium edge, that's just ripe for IVA to fail. 3D printing to the rescue there! Behind the dash it's easier though, the current connectors are in quite close proximity and would be stable enough to hold the wires on their own but it won't take much to add a couple of cable tie brackets to make it extra secure. I'll have to remember to position some next time I get the glue out, which will be when I come to put the fuel filler together. But that will have to wait until I get some more PETG for the 3D printer, I've actually run out of a roll! Only the second roll I've managed to finish too, I must have been doing a huge amount of printing recently. 

Fuel filler

 One more post about the fuel filler, just for my own memory to be honest. The fuel filler neck arrived;

And thankfully it was a usable size, this photo compares it to my moulded one. It's maybe a little larger which is fine. The main frustration is that the Ebay listing said it was new, this was far from new. I don't think it's been used, but the chrome is so tarnished that it looks like it's sat in someone's toolbox for years. It's annoying, but not worth trying to get a refund, after all it's still usable.

The only thing was the angled edges that the cap locks on to, they were simply to severe for the cap to lock. This was expected, I knew I'd be out of luck to get them to work perfectly. Fortunately a few minutes with the dremel got me a shallower angle that the fuel cap could lock to. So that's that.

Now comes the fitting. My idea had been to weld a steel collar on to the tube that would sit inside the bodywork. This neck would then protrude above the body, with maybe a decorative trim to finish it off. Problem is this neck is actually wider than the two inch tube, so I'm not going to be able to weld a collar on and get it to fit through the body. I could make the body hole wider for the neck, but then I'd need to trim it. And again, because the neck is wider than the tube, the trim wouldn't work either. 

I think it's an opportunity for some more 3D printing... Basically I want a bracket to sit under the body. The internal diameter will be for the tube. Then I want an upper lip to fill the hole in the body where the neck needs to fit through. Then the overall part should be wide enough to fix the tube to the body.

Or... I can do the same, but have the tube come in from above. That way I can make the hole only big enough for the tube rather than the neck. I could still use a 3D printed collar to bond everything in place. That would mean I wouldn't need an outer trim, I could just make sure the bodywork hole is tight against the tube. The neck itself would then sit just above the body.

Oh, but that introduces a new problem. When I lock the fuel cap, it needs me to press down on the cap. If I do that too often, I might end up pushing the tube through the collar. However that could be mitigated by my gluing approach, if I use two halves of a collar then I can more easily apply epoxy inside the collar. I could then use a jubilee band during gluing to really press it on there. 

I could also reinforce it by using another 3D printed collar underneath the neck lip. It doesn't need to be much, just enough so the neck sits proud and so the cap has about 1mm clearance to the bodywork. I don't want it to sit on the body because that would scratch the body over time, as well as make it difficult to lock as things wear.

Right, that's my notes sorted, I can come back to that another time. My task for this weekend is to get the loom sorted, or at least get the spaghetti sorted. Even if I don't get all the way to the dash, at least I could get the engine ready to run. Two solid days should be enough, as long as I don't make excuses to avoid it. Like writing a blog post on how to fix a fuel cap...

Metal/epoxy moulding and other things

 I'm sure I'm missing a few photos, but here's what happened...

Firstly I modelled a gas cap neck end in Onshape and printed it out;

Once I'd checked it worked ok with the cap, I printed a negative, basically a mould;

(The real thing would not have photographed very well, even this 3D model is difficult to visualise). . Then with nearly a full tube of JB weld I filled the mould;

I did try some release agent on the mould, hence the discoloured wood that it's sitting on. Unfortunately the release agent did very little as the epoxy had managed to get in between the plastic threads. At least I knew it was a good adhesive!!

Once it had cured, I set about removing the mould. It had to be done essentially one layer at a time, and in doing so I actually broke the thing I was moulding. That was a little disappointing, but more epoxy and I was able to get it back to it's final form. This is the original printed version alongside the new moulded version;

And... it does work surprisingly enough. It's certainly strong enough to cope with holding the cap on, it needs some fine sanding just on the edges to make the action smoother though. The epoxy worked so well that it duplicated the 3D print layers, which means the surfaces are rough.

Of course, in the meantime I did find a filler neck for a Royal Enfield bike that could actually do the job, so I have one of those on order. If that arrives and works I'll use that instead.

In other news, the gauges are progressing well. I'm adding paint on the bezels now;

A bit more sanding, painting, sanding and painting will get me some decently smooth surfaces. I've also cut and polished the acrylic faces;

I needed a lot of elbow grease and some watch face polish (polywatch is the name). It worked well to be honest, it got rid of most of the hazing. There's still a few tiny marks but hopefully they won't be seen once they're mounted in place. 

I've also added one layer of knifing putty to the hub caps, once they're dry I'll need to sand them;

By the way, knifing putty is really hard to work with. But on the good side it does mean it'll be quite tough. It needs a good sanding and shaping, and for some reason I'm missing one. I only had three when I came to do the putty work. 

And lastly, an update on wiring. It's horrible. That's the update. I can see why it's left until the end, and many builders opt for an aftermarket loom. However I do have most of it done, I've got maybe a dozen wires left. I've temporarily mounted the two fuse boxes in roughly the same position they will be in the car;

The spaghetti is what I need to get rid of. There's two main power feeds that go to most of the sensors and connectors, then there's fuses for a few extras (EG fuel pump). Many of the fuses aren't used anymore, if I put my mind to it I could have replaced both blocks with a smaller unit. But for now I'm staying standard with all the challenges that brings.

Oh, and Mr Insomnia kicked in last night with an interesting question... where did the dashboard connectors go? I've got the one for the ignition switch, but there's one required for the indicators and one for the lights. Oh, and the horn (why do I keep forgetting the horn?!). From my 'donor photos' I can see three connectors that look like they would have been at home on the column;

Two white connectors and one black. Hopefully they will match up with 'something' on the extracted loom!

Another fail (fuel tank filler)

 It was all going quite well so I was bound to trip up on something. The plan for the fuel filler neck was to weld a plate to the end of a tube, then cut it to shape. Actually, scratch that, the original plan was to buy a filler neck, but it turns out the ones I was watching on Ebay are the wrong size. So the alternative was to DIY it.

The job started ok, once I'd ground back the welds I could see some pinholes so that wasn't a surprise. Cutting the end hole to size got the cap on, but it wasn't tight enough. Regular fuel filler necks have a gentle slope to pull the cap tight so I had to replicate that. Not too bad, a few taps with the hammer and I got the right angle to pull it tight.

Problem is this is where it came unstuck. I'd effectively broken the welds to make the slope, so it was no longer one piece of metal. And of course, now everything was thin, welding just became a game of 'chase the blow through'. Unfortunately while other locations could tolerate blobs on the other side, as soon as I had one weld on the inside the end became useless. 

So it's back to the drawing board for this one. The issue is that I need to have a flat surface on the top for the cap to seal against, but then a sloping surface for it to tighten up against. And everything I can come up with either covers one or the other, not both. 

My next thought is some form of mouldable metal to make the shape, something like SteelStik or cold weld from JB weld. If I 3D print a mould I reckon I could get it quite accurate, but would it be strong enough? I'd add a flange to attach it to the body, and if it was strong enough I could attach the fuel pipe straight to it. I'll see how good my 3D skills are first! 

New toys

 First an update on the tank. It was another miserable welding job, I hate working on metal that thin. Loads of pinprick holes that needed rewelding. But I finally got it done and pressure tested. This is just before welding it up, showing the flexi pipe in it's proper home;

I think it looks perfect, and it's clear of the roll bar brace. After this picture was taken I welded it up, painted it and put it away ready for the other end.

Oh yeah, the other end. So this arrived;

£40 for an vented lockable gas cap and this cover that goes on top. I don't know whether this particular cap is IVA friendly, if not I'll just go with the standard gas cap. Not as pretty, but safe.

Now the problem was what to fit it to. I got this first because I wanted to see how wide the cap was. Turns out it's wider than all of the Ebay bookmarked pipes so none of them are any use! However it's a perfect fit for my 2 inch tube. So the plan is to weld a flat plate to the end of the tube, then drill and cut a suitably slotted hole in the tope for the cap. Once that's done it's another bit of welding to fix a mounting skirt to the tube for the bodywork. So definitely the locost version.

The only thing I do need to consider is keeping it fuel tight (again!) and also having it perfectly flat on the face. Thankfully I have access to both sides so I'll be able to tap and bend it where required. It needs to be flat to seal to the gas cap rubber, otherwise it's going to be an instant fail. I think in theory I can put the cap on the tube then fill it with water to see if it's tight.

Last thing is the switch gear. I finally found somewhere that sold bog standard toggle switches, or at least I thought they did. Turns out they were momentary flasher switches rather than on/off! A quick disassembly and remodel of the switch mechanism got me a pair of on/off toggle switches. Then it was back to the 3D printer for a mount;

The first one on the left was just way too small in every dimension, not sure what happened there. The second centre one was better, it had the front edge trim on and it looked ok on it's own. The switches fitted, but when it came to screwing on the collars it didn't work. So another couple of millimetres in every direction got me to the one on the right. Now that's just waiting for me to add a legend and the perspex. 

For perspex I managed to get small sheets from Hobbycraft, even in a buy two get one free offer so I have some spare material. It looks ok but I've not yet tried cutting it yet, that will be the main test. If it cuts and/or grinds down then I have enough to make face plates for all dash gauges, tell tales and switches. If it doesn't then I've wasted £6, hardly a dealbreaker!

Last bit of dash

 There is one last bit of dashboard work that I need to do, and that's switches. Most of the switches are dealt with by the column stalks, so that's indicators and lights. What's missing is the fog light and the hazard light switches.

As with everything I do, I started out really complex. I had in mind that I needed IVA compatible switches that illuminate with the correct colour and symbol. Of course, in reality I didn't need it to be like that!

First thing, IVA. This is actually a simple fix, I just need to make sure the switches are in the exempt zone, which is 127mm outside of the steering wheel. Given that is pretty close to the side of the car it means I can put the switches anywhere on the right hand side panel. Which is actually where I wanted them for aesthetic reasons, it means that once again I'm able to keep the dash as clean as possible. Staying within the exempt zone means that I can go with pretty toggle switches rather than dumpy IVA friendly ones. 

Second, illumination. I thought that they both have to have tell-tales associated with the switch, but they don't. They only need tell-tales 'somewhere'. Well, on the MX5 the hazard flasher actually triggers the left and right direction indicators which is a valid tell-tale for IVA. Similar with fog light, I've already incorporated a warning light into my dash lights so I don't actually need to do anything more. Obviously the correct colour and symbol has already been covered.

The only requirement now is that the switches are correctly labelled. At the moment I'm thinking of taking inspiration from my existing lights;

This is a set of seven inline. If I use the same design but aim for a '2x2' pattern, it means I could have the toggle switches in the bottom two, and them symbols in the top two. I wouldn't have the symbols looking the same as these, I'm possibly thinking white symbols on a black background would be best. What I'd do is print an inverted image on to acetate, then paint the back of the image with Tipp-ex to expose the white symbol.  

It does mean I still need to find some attractive toggle switches, which is actually proving to be quite challenging. It's not as if they need to be complex like on other cars, even the hazard switch is just a single pole to ground. The flasher unit deals with the complexity. 

And I do need to get some perspex or similar, that would allow me to finish the dash. I seem to remember hobbycraft do smaller sheets, the DIY places do panels suitable for greenhouses etc which are just too big. 

Tank surgery

 At the last car show in Newark, I bought myself a short length of fuel filler hose, just to finish off that particular job. Shouldn't be too much a problem I thought... then I got home and remembered how things sit;

Unfortunately the distance from the fuel cap location to the tank is longer than I remembered. It's also way too sharp an angle. And finally the roll bar support is in the way. Here's a better view of the issues;

Last night I had a thought about making a steel pipe to get from the tank to the filler location, but even that is not possible. So unfortunately it's going to be open surgery on the tank. Quite extensive open surgery in fact. What I did spot was a gap on the side;

There's a sufficiently large gap between the corner of the tank and the roll bar support. If I move the end piece to the side of the tank, it then becomes a shorter distance for the fuel filler pipe to travel. It's also a less severe angle to get to the filler, which means I can use the length of flexi filler pipe that I have bought.

The downside to that is I need to remove the end cap and the existing filler hole, and replace the lot with a repositioned hole. It's not going to come off without a fight so it's going to have to be a fresh piece of metal. And of course it's only thin steel to start with so that's going to be a fun task again. My wife described the tank as 'home made', and that's purely because of all the extra welds that had to be added to solve the pinprick holes! Still, I don't think any of that is a bad thing, I've got a lot more experience with welding so I might do a better job this time round. 

The last thing that is a worry is that I open up the end plate and find the tank is rusted to hell inside. This has been sat for many years, and in theory it's been sealed but water seems to find a way. Fingers crossed it's not too bad, but if not it'll be a whole new tank. I still have steel so it wouldn't cost anything other than time. I've got some 2 inch tube left over from my exhaust, it's not seamless but there's no requirement for seamless for a fuel tank. 

(Follow up from Wednesday)

So I got it cut open, and actually it's not too bad inside;

The surface corrosion is limited to the heat affected zone of the welds, and it is just surface corrosion. A wipe with a cloth gets rid of it. The edges are all rippled, but that's partly where it's welded and partly where I've taken the end cap off.

It looks really good after cleanup, the edges are pretty straight and I was able to make a template;

The lower half is the end plate with marks for folding into shape, then the top will cover the cutout section. It's marked up but more for riveting and welding.

Oh yeah, that's one thing. The metal seems to be 'pinging', IE it's going from one position to the next due to either tension or compression. That means that it's only straight in one state. So I'll need to hold it in place while I weld it. I'm thinking a series of temporary rivets will do the trick, then as I weld things into shape they will hold the surfaces together. 

I do need to insert the tube, which is the whole point of this exercise, but I also don't want to make things awkward when fitting the end plate. If I fit the tube before putting the cap on, I can get the weld done well but have a chance of warping the metal. Whereas if I cap it first then put the tube in, I can get things straighter than they were but the tube insert might then warp things. 

Either way I've got to be very careful here, I'd rather not have to go on the hunt for microscopic holes again. But I also don't want to blow through the metal as it's really thin. I might do some practice runs on spare tin just to see what I can drop the settings down to. 

(Thursdays update)

The cap is working quite well. The corners folded a lot better this time, I guess watching a whole load of random panel beating Youtube videos does actually improve things! This is the current state;

The sides are pretty tight although the plan for using some fixing rivets is still the best idea to really get things snug for welding. The tabs on each corner will be trimmed and then dressed round the tank, with rounded corners on all four sides I need to make a rounded cap. I've just noticed from this pic that I can see some paint underneath the new part, that'll have to be cleaned up before I weld. 

Talking of welding, this is my current welding setting;

So the toggle switch is at max, the rotary is at 2, and wire feed is at around 7. This works well for the steel I use, but is way overkill for this tank. Checking the manual it reckons 1mm to 1.2mm for these settings, given the fuel tank is 1mm I think that's wrong. I'm going to drop it to Max 1, with around 5 on the feed. That's good for 0.6mm to 0.8mm.

By the way, I think I might have mentioned this before, but these Clarke units are really good. While I started with an Aldi special, that burnt out after a year or so. This one I got second hand and had already lived a very long and hard life judging by the condition of it. A clean and replace of the consumables and it's alive again. The only real issue I have now is the wire feed knob, it has literally no resistance so it's really easy to knock it with the torch lead and set it too high or too low. I think a protective shroud might be useful, something to stop it turning by accident.

So the plan for tonight is to do the corners of the fuel tank, then the weekend will be welding it up and pressure testing it again. 

(Later that day)

The corners are now done;

I'm also happy with how the temporary rivet fixings are working. It's really able to clamp those surfaces together so I can get a good weld seam. Yes I have half a dozen extra holes to fill in, but that's easier than a potentially leaky seam. So that's all set up for welding, once I've had a bit of practice on some scrap.