Photos of Pattern plate, which will go on the timing cover.
 (For those interested!) First op, packet 0.2 mm deep using 0.6 mm end mill. This was done at 0.05 mm levels with 50 % step over 10000 rpm at a feedrate of 170 mm /min. Second photo, same feeds and speeds but using a 20 degree d bit, 0.2 mm at the pointy end.
I finished off using another d bit about 0.1 mm and a toolpath that travels around each letter to a depth of 0.15 mm. This toolpath is called on my cam software V carve.
The outside cut out with 1.5 mm cutter and finished off with 1 mm end mill.
The pattern plate will be filled with black enamel and then cut back flush with wet and dry. The paint is in powered form and fired in the oven at 150 degrees. I have not used this technique before and would be interested in anyone who has and has any tips.

Looks like I am late to the discussion.
Here is a 3D printed metal thread that has been around for a while.

https://www.modelenginemaker.com/index.php/topic,7391.0.html


and also a more recent thread here:

Post #1401:
Part 45    3DP printed metal parts for the coolant, crankcase vent and exhaust pipes
https://www.modelenginemaker.com/index.php/topic,5142.msg301784/topicseen.html#msg301784


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It is an impressive technology.
Changes the options/perspectives of how one can build model engines, with some interesting twists.
Sort of leapfrogs right over CNC, and over a lot of traditional casting methods too.

3D printed metal is not in the cards for me at the moment, but I can see where this would be and already is very useful already to many in this hobby.
I expect this method to continue to become more popular over time.

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Things have moved on in the ten years since that article was written so watch what you find with Google. And if the current metal prints are OK for aerospace, F1 cars, etc then likely to be more than upto what we need from our models.

One of the big advantages of the printed waxes over conventional is you don't have to worry about getting the wax out of a silicon mould and you also eliminate the need for a master and the silicon mould to cast the waxes in. But still being a two stage process is more costly than printing straight off with metal but does offer a wider range of metals.

Another advantage of the online suppliers is they offer instant quotes so you can soon get an idea of what a printed metal part may cost even just by uploading a basic design. Then with the knowledge of likely costs can then develop the design to suit whether you still want to use 3DMP or more traditional casting/fabrication/cutting from solid.

If it is a small item it may well fall within the minimum job cost that a lot of the online companies use so worth playing about with quantities or grouping jobs together. Those two prints I posted earlier would have cost me about £50 each had I ordered them individually but the two cost £55 when put on one order.

Costs are partly based on volume so it is also worth roughing in any holes or cavities. As an example I priced the solid version of the attached pump up to get an idea of costs. I then went back and added all the cores and roughed out holes and the cost came down by 20%. It only cost me a bit of time infront of the 'puter rather than having to make several core boxes and mould the cores.

Interesting 

Do you think the body could be turned down? To what size?

For a manifold injector it could be glued into an injector body. Easier than a cylinder injector.