V-twin engine from scratch - yet another interpretation of how (not) to build a

[sorveltaja]

...model engine.

So far, I've managed to gather some materials:


Lump on the left, that says 48, is pearlitic cast iron, besides are two smaller pieces hacked out of it. Next is a 28mm(1.102") brass bar.

Aluminum piece is 50x50mm(~2"x2") bar.

At the front are two thin walled (0.2mm(0.0078"))steel tubes, that are going to be tested as cylinder liners. They definitely need a cylinder body to support them.

[Bernd]

That piece of aluminum looks like what's left of a "meat tenderizer". 

Nice collection of raw stock. Am I right in asuming it's going to be two cylinder?

Bernd

[sorveltaja]

Bernd, yes it's going to be 2 cylinder, 4 stroke v-engine. I'm considering making overhead valves, as there could be a bit more room to adjust them.

I prefer side valves more, but at this small scale they are rather difficult, although possible to adjust, as on my previous test engine.

Anyway, there's still lot of things to figure out on the design .

[Brass_Machine]

Coolio. Love V-twins. Is it going to be a narrow twin (ala harley, S&S) or a L-twin (like Ducati?)

Eric

[NickG]

Nice 1 S,

This should be very interesting to watch develop much like your previous engine.

Nick

[sorveltaja]

Eric, it will be something like 60 degrees v, although I've read that 90 degrees would have less vibrations.

Here is the first candidate for crankshaft:


It gives a stroke of about 15mm(~0.59") and bore will be smaller than that.

Axle has 4mm(0.157") diameter. 

[sorveltaja]

That piece of aluminum looks like what's left of a "meat tenderizer". 
Bernd

Hmm.. almost right. That's just how I cut the bigger stuff. First cross-drilling, then some delicate butchering to part the stuff.
~Where art thou, my beloved chainsaw~, as Hamlet would say.

But to the point. Aluminum block, that'll form the crankcase, is almost prepared for the lathe, and then for milling operations. Good chance to test my angle milling skills.

[Brass_Machine]

I vote for over head pushrod valves

Eric

[sorveltaja]

It's been bit quiet, because my lathe's belt snapped. It's now fixed, so back to project.

It seems that my lathe is seriously underpowered, what comes to that 50x50mm alu piece. Machining it is even more tedious, than I expected .


I looked an alternative for solid crankcase, and found out, that the Hoglet type would be much easier to achieve. Being scratch built part, it suits the spirit of this project .

Two small bars are 20mm(0.787") SS 2172, that is available nearby store . It machines quite well, so I use them for cylinder liners.

[Krown Kustoms]

Very nice so far.
I will keep up with this one:)

[sorveltaja]

Some progress on crankcase:


In the middle are the 5mm(0.196") alum crankcase walls, that have 13mm(0.511") holes bored for bearings. Smaller holes are for supporting rods. I'll make them after those two plates on the sides are fitted in place.

I'm going to make a new crankshaft, that uses split end -connecting rods. Don't remember what it was called for, but anyways same kind of, that is used on multiple cylinder inline- and V-engines. That way it's possible to support the crankshaft at both ends.

[Rob.Wilson]

Looking good , one to keep an eye on , sorveltaja do you do any drawings for your engines or do you design as you go ?

Regards Rob

[sorveltaja]

Rob, I've made some basic sketches, and modify them if(when) needed. Non-critical parts are done without too much precision, so that's why I need to mod the drawings as the project goes.

After all, most important thing is to get all the parts to fit together .

[sorveltaja]

Plates fitted in place:


It was more difficult to match those two parts, than I thought.

Angle is right, but I removed too much material, leaving an ugly gap between them:


Fortunately it isn't too crucial thing. Making the two crankcase walls parallel is more important.

I made the backstop for the lathe spindle, so the two supporting rods can be made equal length.

[sorveltaja]

That gap bothered me, so I had to do something about it:


It's not only cosmetically better , but the brass bar also adds more meat for the cylinder screws.   

On the above pictures, supporting rods are in place. Construction feels now quite robust.

Next thing to do is a new crankshaft.

[Brass_Machine]

Looks cool too! 

Eric

[sorveltaja]

New crankshaft parts are almost ready to be silver soldered together:


Axle and shaft are 4mm(0.157") stainless.

[sorveltaja]

New crankshaft before...


...and after cropping excess material off, and some cleaning:

[sbwhart]

Looking good

Have fun

Stew

[Stilldrillin]

It`s all shaping up nicely! 

David D

[sorveltaja]

Bit of progress today:


Cylinder plates that are screwed in, are 1.5mm(0.059") mild steel, and have now 10.5mm(0.413") holes in them. Holes are to be bored to 13mm(0.511") on the lathe, as my small mill/drill press doesn't have the power to handle that big drills.

[Rob.Wilson]

Another very interesting read/build  keep it coming


Cheers Rob

[sorveltaja]

Cylinder plates bored to 13mm, and fitted to place:


The brass piece needs slots to be filed to give room for connecting rods:

[sorveltaja]

First cylinder liner bored to bit under 12mm(0.472"):


That SS 2172 machines well for outside turning, but boring it is much more tedious.
Also the surface is really rough, so lot of manual labor is to be expected to get it smooth.

[sorveltaja]

New brass cylinder bodies:


At first I was going to use the same method for cylinders, as on my previous test engine. Being that the cylinder liner is silver soldered to cylinder plate.

In this case, it would have been too complex. So I made some measurements, and noticed that I have just enough of that 28mm(1.10") brass bar to make two cylinder bodies, and perhaps the heads also.

Cylinder bodies still needs to be bored, for liners to fit in. Also some holes for screws. They have quite a rude cooling fins, but, after all, it suits well for the project.

Two remaining cylinder plates make an excellent drilling jigs anyway .