Bugatti Typ 50 1/4 Scale model

[michelko]

march 2015
working on the cylinder Barrels. Tey are made of ETG 100. This is an easy machinable high strength steel.
it has a tensile strength from 960-1100 N/mm^2.
The inside Diameter was bored and reamed to a smaler Diameter the spec becaus i had the reamer.
The cilinders was then taken on an arbor to machine the outside diamter to spec for pressing them into the block.
After pressing them in the inner Dia was bored out to approx 3/100 below spec. The rest was done by lapping with  valve lapping compound and a fabricated mandrel.

[michelko]

more pics

i also used Loctite to surely seal the Barrels into the block. My first idea was to use thin O-rings.

[michelko]

April 2015
milled the cilinders flatt to the block and did the boring.
Some time ago i was able to buy a Ultra cool boring head named wohlhaupter upa2 for realy small Money. As it arrived by mail, i saw that it was never used . This is realy some fine tool.

[michelko]

Wohlhaupter in action

[michelko]

may 2015
seems i didnīt take any pics from lapping the cylinders.
Here are the pics with the ready work. Last pic is the tool to do the measurement of the inner Diameters.

[keith5700]

Michael, you are going down exactly the same path I went down with using any sort of plastic insulator in the spark plugs. In a previous post I mentioned about the pressure tester I made. This showed that when the spark is under pressure it is very much reduced in intensity. I can only think that this is why everyone who uses ptfe or corian insulators seems to be ok.
Our problem is that when the wasted spark fires, on the inlet stroke, it isn't under pressure, so is far fatter, and I think this is what is melting the plastic insulator.
If you aren't using resistive leads then it will just make things worse.
This is one reason I have gone to full sequential ignition on the v10, so I now have no wasted spark.

I still had the problem of internal tracking in the plugs. In the end I resigned myself to paying out for the proper machineable ceramic, Macor, and making the first 30mm of insulator from this. The back end of the plug is still ptfe though. My plugs are about 60mm long.

I also found a plain butt join won't work, between the Macor and ptfe. You need to make a stepped joint to prevent internal tracking. I'll get a drawing up if you're interested, but it won't be till Wednesday.

I ended up using a 1mm diameter electrode. You'll need some decent drills to get through the Macor, but it is possible. If you plugs are fairly short then it should be easy.

If I do another engine I will most certainly design it around one of the commercially available mini spark plugs.

[michelko]

Keith, i will be glad to see the drawings.
My ecu doesnt support 8 cylinder sequential. What ecu are yue using? I am using a ms2 on my classic car, but i think it also can not fire 8 individual plugs.
I think i will build a little pressure chamber like you did from acrylic glas just for curiosity but i am sure the first set of plugs ist shot and useless.

Michael

[keith5700]

Michael, I'm using MS3, but this will only do 8 cylinders in sequential mode. I had 2 extra ignition drivers installed. I don't think anyone's done a 10 cylinder full sequential Megasquirt install on full size yet.
Not that I could find anyway.
I had my MS2 upgraded to MS3 and the 2 drivers put in for Ģ300.

[Roger B]

Michael, The shape of the end of the insulator is also important. The spark will track along a surface more easily than it will jump a gap. Typically the length along the surface should be at least 5 times the gap. Sharp corners on the insulator will also encourage sparks. In his V10 thread Keith has a number of drawings of different designs.

[michelko]

Hi guys,
next part was the oil pump in December 2015. It is a gear pump driven by the crank. I made a spray bar that is spitting oil onto the rod bearings. Then the oilline is routetd to the valve tappets. each valve  bank has also a spraybar where the oil is directed to each single cam and ist Follower.
The gears are made from brass. milled them with my cnc dividing head.

[michelko]

the caverns of the gear pump where made with the boring head. For a good allignement the cover and the Body where bored together.
Using brass bearings in Aluminium Body.

Here is a Video from a test Setup in the milling machine.

<a href="https://www.youtube.com/watch?v=BP0oItnOI7Q" target="_blank">http://www.youtube.com/watch?v=BP0oItnOI7Q</a>

[michelko]

january 2016 oil pump mounted to the engine, soldered the suction pipe.
Also did the gear housing for the valve Timing gears.
Small dowel pin for the Fixing the first gear to the crank.

[michelko]

Machining the gear housing from two pieces screwed together.
first step was milling out the inside then screw the pats together and screw both to a fixture

[michelko]

fitted to the block
Some gears to see

Michael

[keith5700]

here are my current plugs. also shown is the insulator from a mini spark plug, and a smaller complete plug from the same source.
I have tried to slim down the insulator nose on my plugs to try and get it to run hot and burn off any oil or soot, which I have been suffering with.
The drill is a mini carbide pcb drill.