200cc approx. hit and miss diesel, could be a long build.

[Kaleb]

After a bit of head scratching and talking to others in the know about diesels, I decided that it may be possible to build a diesel using an off the shelf injector from a Yanmar or Hatz engine using the facilities I currently have available for most of the work. The only thing I can think of which I'll have to go to someone else for are the teeth on the gears.

It will have a 60mm bore and a 74mm stroke. The flywheels will be 220mm in diameter.

Here's some of the CAD I've done so far. I've still got a way to go here, but it should give some idea as to the appearance of the finished engine. I will be making plans available once I've got a complete set done.

A scrounging trip a while ago yielded a pair of main bearings.

These are the gear blanks. I've still got some work to do on the larger one. The smaller one just needs the teeth cut and holes drilled and tapped for grub screws.

 

[kf2qd]

Not sure those bearings will be up to the task. Ignition puts quite a bit of impact force down into the bearings.

 

[kuhncw]

Hi Kaleb,

Why do you call your design "hit and miss"?

Regards,

Chuck

 

[Kaleb]

That's because it will be hit and miss governed.

 

[dmac]

Watching with interest Kaleb. I've never scene a diesel hit and miss engine.

Dave.

 

[Herbiev]

Our next Team build ?

 

[gus]

The "Y " bearings will make up for slight misalignment. I used them for heavy roller conveys. For 3 long years it ran with minimum greasing. Might be smart to inspect visually and hand rotate to look for decfects like rust and pitting. Can I imagine these bearings are not bad news from China.

 

[kuhncw]

That's because it will be hit and miss governed.

I understand hit and miss governing on spark ignited engines, but was surprised to see it mentioned for a diesel. How is this done on a diesel?

Regards,

Chuck

 

[Kaleb]

The "Y " bearings will make up for slight misalignment. I used them for heavy roller conveys. For 3 long years it ran with minimum greasing. Might be smart to inspect visually and hand rotate to look for decfects like rust and pitting. Can I imagine these bearings are not bad news from China.

Well, I know one of them is an SKF, the actual bearing in the other one may be "bad news", it's marked JIB or something like that. They feel nice and free. Even if one is Chinese, I got them for nothing, so I'm not going to complain unless it packs in.

 

[Kaleb]

I understand hit and miss governing on spark ignited engines, but was surprised to see it mentioned for a diesel. How is this done on a diesel?

Regards,

Chuck

The hit and miss governing on this engine will work a little bit like that in a spark ignition engine. The exhaust valve will be held open when the engine is up to speed, but the difference is that the governor will also operate a valve that causes fuel from the injection pump to be sent back to the tank rather than being injected into the cylinder. The exhaust valve will be located in a recess in the cylinder head to prevent it from fouling the piston when the engine is missing.