Pierburg 2E3 choke

[silverbullet]

Very impressed. SLS is clearly becoming a mature technology (and yes I do read the engineering and manufacturing tech press!)

[CJH]

SLS is clearly becoming a mature technology...

Yes, it's happened surprisingly quickly, but that's something of a rule isn't it - new technology always catches on quicker than you expect. It's partly down to the foresight of companies like Digits2Widgets I think - with the skills and resources to turn a profit from what must be very expensive equipment. They have in-house CAD people to support new customers, but above all they have developed a super-efficient way of dealing with customer orders.

I think we'll look back on these early days of 3D printing with amusement. Printing in metal is still in its infancy, but imagine being able to print your own pistons, or aluminium crank case.

Tea, Earl Grey, Hot....

[silverbullet]

I still think smartfones to be "Star Trek".
Kids today...

[CJH]

I still think smartfones to be "Star Trek".
Kids today...

Did you have a Razr too then?

What's great about 3D printing is that it can make things that simply couldn't be made any other way. Just think about the design that's gone into this digital sundial for instance - the shadow it casts shows the digital time in 10 minute increments. It would be almost impossible to make that via any other process.

[Mocki]

That is just amazing ..... It's actually hurting my head thinking about how the hell that can work!

[silverbullet]

Just showed that to my daughter. She was genuinely impressed. At 13!!!
(I explained the idea of the changing angle of the sun causing the holes to let light through or the webs blank off others, so changing the displayed digits)

[kevtherev]

We have two printing machines in the aluminium engine casting business.
These machines are allowing more and more innovative and complicated cylinder head/ inlet manifold/ exhaust manifold cooling/heating systems.
They build sand in complex shapes that no traditional process can replicate
Customers can come in with an idea on a fag packet and see it fully cast and integrated into an engine in days!

[CJH]

They build sand in complex shapes that no traditional process can replicate

That's a neat idea. What binds the sand together Kev?

[silverbullet]

Magic

[CJH]

I thought the throttle part was pretty much there, but when I tried it fitted to a carb I noticed a subtle difference. The small lever dictates how much the secondary venturi flap can open, under vacuum from the attached diaphragm, before the primary venturi is fully open. Here's what it looks like with the copy part.


And here's what it looks like with an original part (on a different carb)


The flap seems to open a little more with the copy part. This is partly dictated by the spacing of the upright arms of the U-bracket, which can be adjusted quite easily, but I've tried to make sure the two are the same. So it means I need to make that small lever a little wider, to limit the flap opening to about the same as an original piece.

So I'm hoping this is the final iteration.

[itchyfeet]

My choke flap links arrived today, thanks Chris

[CJH]

My choke flap links arrived today, thanks Chris

Before you go and rebuild a carb around one of these, I've decided I'm not happy that the holes came out bigger than I intended - they create a bit too much slop in the linkage for my liking. I don't think it matters, but it would be better if it wasn't there.

So I'm going to tweak the design a bit and then include a batch in the same container as the throttle part order. If I go up to their next container size, there's less wasted space in the container, and the cost per unit volume is slightly cheaper. After doing some proper sums (i.e. correcting a mistake I made about how many throttle parts will fit in one layer in a container), I reckon the costs I gave earlier are about right. So the corrected choke piece will be £1, and the throttle piece (including a spacer and a couple of rivets, to allow for mistakes!) will be £1.50. Post and packing for any number will be £1.

I'll continue to post out the 'sloppy' choke parts from the first batch free of charge, but the second batch should be better.

Incidentally, I noticed today that the vertical position of the choke flap is defined by the end stop inside the choke coil housing, so that little triangular end stop on the choke piece seems a bit redundant after all that.

[itchyfeet]

Incidentally, I noticed today that the vertical position of the choke flap is defined by the end stop inside the choke coil housing, so that little triangular end stop on the choke piece

Not on mine, the choke flap link hits the carb body first when flap is dead vertical, the choke coil lever stop hits a bit later.

Been trying to work out ths path of all the carb drillings today, it's made my head hurt, really quite complicated.

[itchyfeet]

just zoomed in on this pic and seen some cheeky VW badges in there

[Mocki]

Hahahaha! Like it