1/12 SuperGT Mitsubishi Evolution IX

[mike@af]

As many of you may know, I had similar 1/24 scale Evo project in progress. Since abandoning that build for a number of reasons, I have regained my interest in building a similar Evo in 1/12 scale.

This version will be a 1/12 scale, Mitsubishi Evo IX in Super GT race trim. The build will be almost entirely scratchbuilt. Most of the design is being done in SolidWorks and machined on my Sherline CNC mill and lathe. I moved to 1/12 scale so more detail can be added, and be more visible on display.

As usual, I like to start with the engine since it is the powerplant and center of the racecar. Instead of machining the engine block, I had it 3D Printed in wax by Kraftwurx. (You can see a 3D printed plastic version of the block in the background)




After I received the wax master, I had a little bit of cleanup work to do, then the master was sent to a jewlery casting company to cast the block in brass. The detail is pretty good, it is about 90% there with minimal shrinkage.




I added extra material to the top, bottom, front, and back of the block to account for shrinkage and warping. Since these are mating surfaces, they must be perfectly flat and precisely cut to within .001" (0.025mm) of the specified dimensions. If the block is not within tolerance, the other pieces will not fit correctly.

The first step was to surface the cylinder deck using a single flute carbide fly cutter.


Once the top of the block was surfaced, I proceeded to follow the same process for the front, back and bottom of the block.


Unfortunately there was more warping on the bottom of the block than anticipated which required extra material to be removed. This made the block too short, so to compensate I machined a new flange out of brass to be soldered onto the bottom of the engine block.


Since the brass is quite large, it requires a lot of heat to be soldered. I used a MAPP gas torch to heat the block and add some solder to the block and piece to be attached. By adding solder before clamping the pieces together, this helps form a joint more easily.


With the help of a friend, I aligned the new flange with the engine block and clamped it tightly in a machinists vise.


Since the cylinder head will bolt to the engine block, I had to machine the holes for the head studs.The threads will be 1.0mm x 0.25mm. First I had to drill the pilot holes for the threads which I used a 1/32 (0.80mm) carbide drill bit.


Last was some uneccesary detail, but fun to do! I used a .040" (1.0mm) carbide drill bit to add the waterjackets for "engine cooling".


Then machined all the cylinder bores to size using a 3/16" (4.76mm) end mill.


More progress to come soon!

[Capri-Schorsch]

Wow,what an awesome start on an stunning project.

Nice milling work so far.
Keep the updates coming.
regards Christian

[michel1973]

Very impressive so far. Must be an excellent result once finished

[yelo]

And why did you ditch the 1/24 one again? I loved that project...

[RunFlat]

Mike your Solid Works\CNC skills get better every time I see it. I'm glad you changed the scale to 1/12th because I know how much detail you want to put into it. Great work keep it rolling.

[lovegt40]

make us dream mike !

[joelwideqvist]

Gosh... This really got me thinking on why I do scale modeling. Adding those never to be seen details really show you want to evolve your skills, learn new techniques and model cause it is so fun rather than just showing off. Inspirational!

[sportracer02]

Great start!! Was the 1:24 modell just a test?

[KC27]

Awesome start. Watching with interest.

KC

[mike@af]

Thank you everyone. This is definitely a fun an exciting project for me to continue with in larger scale.

Originally Posted by yelo

And why did you ditch the 1/24 one again? I loved that project...

Originally Posted by sportracer02

Great start!! Was the 1:24 modell just a test?

I really wanted to finish the 1/24 scale project, but I hit a point where I had to decide if I wanted to commit to it, or move to 1/12 scale. I decided that I would not be able to add the level of detail I wanted to achieve building in 1/24 scale. Building in 1/12 scale allows to me to add much more detail - which can be more easily seen on display.

Perhaps one day I will finish the 1/24 scale engine, but for now, it is just another item to display on the shelf.

[firun]

Unbelievable!

[mike@af]

Thank you everyone for your support and compliments!

First off, my apologies for not having any great photos of the wax master for the cylinder head, I was about to head to the airport for a business trip when this arrived and wanted to get it sent to the casters as soon as possible. I digress.

Major thank you to my friend Daniel (TheSilentChamber) who took up the challenge of machining the cylinder head out of jewelers wax on his 5-axis CNC mill. The resolution and quality of this master is incredible - almost smooth as glass. As you can see, there is some sprue out head for casting purposes


Matchstick for reference.


Daniel did a phenomenal job machining this piece, down to every detail.


I sent the master off to be cast in brass. (This is a little out of sequence since I had the head cast before the engine block.) When the casters received the master, they called to tell me it was one of the most complex pieces they had ever tried to cast in brass. The result was phenomenal.





Once I cleaned the cylinder head up and machined the faces true, I used CA glue to temporarily attach it to the engine block. By gluing the head to the block directly after drilling the head stud holes, I could ensure the head stud holes would be drilled in the correct location relative to the block.

Here I am machining the seats for the head stud nuts using a .065" (1.65mm) end mill. The clearance holes were then drilled with a .040" (1.0mm) drill bit.


Thanks for following! Next I will get into some aluminum machining for various parts.

[TheSilentChamber]

Heh, I love that you can see the wax get translucent on that back wall of the cylinder head, crazy thin in areas. Was a fun project to mill!

[nugundam93]

wow. while we do yearn for the 1/24 build to be done, your reason for switching to 1/12 is perfectly logical. now one more great build to be excited with!

[icon_modeler]

Really disappointed to see that the cylinders were not bored and honed how do you expect the rings to seat and get any kind of compression???

That's a joke everyone!!!

Nice work Mike, this should be even more unbelievable then the 1/24th scale counterpart.