Exhaust design is finished

So, after the first couple of attempts at making the exhaust, I realised I was designing and printing myself into a corner, so I decided not to print anything else until I had a full design I trusted, to the dimensions I wanted, and this is it … this is version 6 of the design.

I’m pleased with it because the worst deviation from spec is pipe 2, at 1.5mm. Pipes 1,3 and 4 are all within 0.5mm of their proscribed length. Length is defined as the distance the gas has to travel rather than the amount of pipe needed to implement that. As such, all my lengths for the bends are taken from the centre-line radius, rather than the amount of pipe needed to make the bend.

By good luck rather than good judgement, each pipe seems to follow on a theme from the other pipes, and they look like they’re meant sensible runs, rather than all sorts of convoluted bends and wiggles. Furthermore, all the bends are from Alunox stock bends, and I’ve managed to keep to the largest radius for smoothest flow.

It has created a slight issue though, in that the yellow pipe fouls the steering column. I can fix that by slightly changing the route of the column, and maybe adding an extra UJ.

Tidying up, and paving way for a rewrite

I like my analogue dashboard, and am very tempted to keep it when I retire. However, getting access to it has always been a pain. Furthermore, the interior of the engine bay from all the mods made previously was starting to get a little tatty, so I’ve solved two birds with one stone. Below, you can see many holes for things like fuse-banks, heater access etc. There is no heater anymore, and fuses/relays will be replaced with solid state relays (SSRs).

Urgh – not made of carbon.

And here we are part of the way through. I’ve trial fitted the panel and fully fitted the rivnuts as fasteners. The plan is the panel can be removed from the engine bay in a minute or two and then full access can be had to the back of the dash. Not every rivnut went in easily – some had to fit over what was an open hole and required small support pieces. However, the plan was always blind-ending fasteners.

Here it is from the back – a much better approach (I think) and you can see the black patch-panels I had to bond in to support the fastener.

Finally below is the finished article. Tidies it up quite well. Added a little weight but I can live with that for the convenience bought. The bottom panel is fully bonded in – I couldn’t see any advantage to making it demountable. The panel to the right with the gaping hole is also going to be relieved and replaced – similar on the left.

3d Printed mock-up exhaust

So, the parts to the exhaust are going together nicely. The plan is to make a mockup of parts I can buy off the shelf, make some clip-together parts to simulate the bends I need, and then buy the parts and build the exhaust. This means I don’t need to cut any expensive stainless until I’ve got the design and the jig completely right for the exhaust.

Prop catcher

So, a few things have moved forward. Bailey and Morris shipped me a lovely prop, and now I’m making a suite of aramid prop catchers for it. The plan is the catchers are printed, moulds taken from them, and then then made in Aramid. They should be light, and easily able to handle the abrasive loads.

xmas holiday summary

Well, it’s been a decent enough holiday – I’ve finished 3d printing the front engine mount, and if the bonnet fits properly (I’ll know on Friday), I’ll flat it, crack a mould off it and make a carbon fibre engine mount – a first for me, and I think I’m blazing a trail a little there.

I’ve also been through the worst man-flu in the history of all mankind, but I still managed to have a good time, relax, read a few books and I’m currently getting through the ‘travellers’ box set on netflix.

Finally, the boxen1 of shame have been put out for recycling and don’t look too bad. Both full, but not priapic.


1 – The pleural of ox is oxen, therefore the pleural of box is boxen. Obviously.