[MuellerNick]

Hi!

Today, I had a break-trough with casting a center-piece of my scale Diesel engine. For me, that's a milestone. And enough reason to show off!

About the engine:
This is a 200 hp Diesel engine off the "DM"-series. DM stands for Diesel Motor. It was built by MAN. The DM series was the second generation of diesel engines that were sold in volumes and they were the first ones that worked quite reliably. There were different sizes. To my knowledge a DM 8 (8hp), DM 50 (50 hp) DM 75, DM 100 and DM 200. At least the bigger ones (starting from DM 50) were available in 1, 2, 3 and 4 cylinder configurations.
My model is a 2 cylinder version with 200 hp (100 hp per cylinder).
These engines worked with compressed air injection.

How that project started:
January 2005, I got a tip that there is an old Diesel engine at Passau. I found a tiny picture and decided to have a look at it.
Having seen it, I realized that this will be my next project.
I tried to get plans from MAN's archive, but they no longer had them. They lost all of them during a fire.
But I'm stubborn!
I contacted the municipal works (owner of the engine) and asked for permission to take dimensions. They were NOT happy. It took some time, and then they allowed me to take pictures, dimensions and even step on the engine.
Together with a friend, we went there. 'Till noon, we sticked about 1500 dots onto the engine, took pictures from all perspectives (IIRC 200) and removed the dots again.
200 hours of photogrammetry work followed ... even more hours on the CAD. And endless hours hunting for books that showed something of the internals.

The result will be a model in scale 1:10.

Here is a picture of the original engine:

You can see the dots that were sticked onto masking tape to increase contract.


And one that shows a detail of the cylinder head. Just so you can imagine the work involved to re-model all those points.

It didn't take too long for me to realize, that I will fail with my equipment and my knowledge.
So I bought a used and MAHO MH 700 C mill with a broken controll and replaced that with LinuxCNC.
Bought a Myford cylindrical grinder and completely restored it. Bought X and Y and Z and repaired it.

Then, finally, when I realized that I somehow forgot what I initially wanted to do, started with castings. That was spring of 2011. Built furnaces (2 of them have retiered), built a muller, built a core sand mixer, built ... ahhhh ... tools to make tools to make tools!

Long story short. Here is my A-frame I succeeded in casting today:











These are the cores that go inside. I had to mill channels as gates and a pool that takes the first shot of cold pour.
This casting has a split pattern with two loose inserts and 7 cores. These cores are made out of 10 parts.
Wall thickness is 3 mm in most places!


I'll show more pictures. But now it's time to go to bed. Will have an other casting session tomorrow and take the chance to show more castings I have made.

If you do have questions, feel free to ask!

Nick

[hi speed scrap]

Well done Nick, I'm impessed with your work and a
nice choice of model.
Castings are Aluminium I assume?
I will follow your build with great interest

Dave

[MuellerNick]

Yes, all aluminium castings. Except the flywheel. But I don't get enough temperature yet. I can melt CI, but it is not hot enough for pouring.

I use oil bound sand. OBB-sand (local brand here in Germany), similar to PetroBond.

The cores are PU-bound (cold box). Two components mixed into the sand. Then massaged into the core boxes and the PU activated with amin (SP?) gas (stinks like ammonia and is chemically similar). The cores are very durable and detailed and do have sharp corners that withstand the heat of the pour.
Unfortunately, the cores have to burned out (4 hours at 500 °C) afterwards. Stinks a second time.

Thankfully, I get a lot of the casting chemicals from a friend and generous supporter.


Nick

[Herbiev]

Wow. That is superb casting.

[Speedy]

do you have the injectors figured out? and pump assuming it uses them, curious.

[cfellows]

Very ambitious project. Will it be a true diesel? What are the bore and stroke of the model?

Chuck

[skyline1]

Very impressive, the patternmaking alone is a major achievement with no proper drawings to go on

Regards Mark

[Niceonetidy]

How does the dot photograph method work for making patterns please?

Really great job, well done,

Colin

[AussieJimG]

What a wonderfully ambitious project!! From measurement through photogrammetry to multi-cored castings. I am awe-struck and will follow this build.

Jim

[MuellerNick]

I have been asked wether I sell the castings. No.
I would have to charge a lot. There are IiIRC 45 different castings per engine. Makes about 150 cast parts for a two cylinder engine.
Making the mold for this cylinder takes over an hour. Making the cores an other hour. Milling the pattern for the cylinder took about 40 hours. Plus the patterns for the cores.
Every part that is a casting in the original, is a casting in the model. No matter now small it is.
And then, there are no plans. If I would draw plans, I would have to spend something like a month for them.

The dots are not used to make patterns. At least not directly. This method is called photogrammetry. Each dot has to be taken at least 3 pictures from different perspectives. Then, you need to know one single dimension. And MAGIC! the dots are all precisely position in space. Import them into CAD and model the shapes, so the do touch the dots. Will drive you nuts!

I do know how the injectors work. I think there is a sectional drawing in Cummin's book. The compressor is two-staged and has something like 70 bar. Won't work in this scale. There are too many losses.

I will try to let it run as a true Diesel, but I have my doubts. I'm thinking about an electronic injection with open jets.

I'll post pictures of all the patterns and cores for the A-frame tonight.

I have about 30 patterns finished. The few remaining aren't complicated.


Nick