Hello everyone,
It been over a year now without building anything like a modelengine and i decided to start a new project.
I hope my build will be of interest and you guys are not angry because i did not post anything since the finishing of my model A engine
....
I will not tell what the original engine is now. Maybe it will be fun to wait until one of you figure it out when the building progresses.....
One original engine i have here at my home and it is teared down because it needs an overhaul. So it is easy to take measurements for the 1:2 scale model engine.
The engine is a four stroke four cylinder engine and still in production......
My modelengine calls for a build crankshaft like the original. I really don´t like build crankshafts and connecting rods that are not removable but the original has a build one so i have do deal with this.....
So here are a few pictures of the build of the crankshaft. I have also startet the mould for the crankcase and maybe i will cast the first part tomorrow or on sunday but the mould is not dry enough now.
The pictures are :
1 : Drilling and reaming of the crankshaft webs interference fits. The stroke of the crankshaft will be 30 mm.
2: Milling the lateral surfaces of the crankshaft webs to exactly the same size. This surfaces will be the reference surfaces when pressing the whole thing together ....
3: Milling the outside shape of the webs
4: Drilling the oil passages. The engine will have pressure dry sump lubrication like the original.
5: Hardening of the crankshaft webs. I think i will only have a chance to get strong enough interference fits when all the parts are hardened. All of the parts are made of C45 tool steel. This is a beautiful and also cheap material ( 0,45 % carbon ). It can be hardened at 750 ° and tempered at 400 °.
6: Crankshaft web after hardening and sand blasting. After the sand blasting i tempered the webs at 400° and cooled it down in oil to get the black finish you see on the other pictures.
7: Most of the crankshaft parts finished. The diameter of the interference fits of the pins is 12 mm . I am a little afraid of them being so small. But the crankshaft of the original engine is also without much safety reserve so we will see.....
8: Setup for cnc milling the four connecting rods. The rods are also made of C45 tool steel. The are not hardened because they will get a 16 mm bronze bearing at the big end and al 10 mm bronze bearing at the piston pin.
More to follow.... Only 8 attachments per post alowed.