Відео

It is open crankcase, which is pre-lubricated before running. Many old (vintage) engines had this design back in the day.

Large gear has 44 teeth and the small gear has 22 teeth

Large gear has 44 teeth and the small gear has 22 teeth

You will have to add an ignition system and carburettor. I never designed an ignition system, we just added it quickly with parts laying around, more or less as an afterthought. The "jampot" vapour carburettor works well and is really hard to mess up, it's also very fast to make.

@@slome815 Thank you so much for replying to me. I really appreciate your feedback and input. I will document the build and credit you in any posts I make. Thank you again. Cheers Aaron (Melbourne Australia).

It is not a scaled up version. It's just a basic fourstroke I designed. As for the bore and stroke, I think it's 30mmx30mm. The CAD model is available on grabcad in case you're interested.

@@slome815 many thanks, I will check the cad out

The pistons were made to have piston rings. But because of a lack of time the the engine is now running without them. This is possible because the clearance between the piston and cylinder is very small, somewhere between 5-20µm. If you want to make piston rings, you first turn the outside and inside diameter to tolerance, then part the ring off on the lathe, split it, put a spacer between the gap, heat it to 800° (it then keeps the gap and acts like a spring) and then grind the gap.

@@slome815 Thank you. I will try it with piston rings. Is it okay to still have about 20 micron clearance or should it be more when using rings?

@@CrankAndCraft It should be fine as long as you use cast iron for both the cylinder and pistons.

Im trying to build my own, but I don't know what to do about the ignition system. Any help is welcome

It's just a microswitch we had laying around. I didn't include it in my drawing, and it was fitted more or less as an afterthought. The rest of the ignition system is an electronic ignition set from "velleman", with the coil from an old car. There are multiple electronic ignition systems out there, this is a bulky system, but if you look at ignition systems for model airplanes you should be able to find a more compact one.

@@slome815 Thanks a lot!

Hey mate, Sander has kindly provided the weblink to 3D CAD files to the description area. It's "grab cad link".

I really would go with either a conical clutch or just a tension wheel on a V-belt as clutch next time. The tire system requires to much force to get it started with such a heavy hammer. It works but it's not as good as I would have liked. The brake is a little more complicated then but it should be doable.

The compression ratio is about 5. It runs on either white gas, 95 or 98. It really doesn't matter at such a low compression ratio.

It's an HEB 300mm I- beam. That would be around 12".

@@slome815 wow, 12 inch beam, it is very large size, look so strong and firm sir.

The spring was a custom spring, I had it made at a local spring making company. unfortunately I no longer have the information with the specs.

@@slome815 no worries. It's a damn nice hammer. Could you at least tell me the dimensions of the ram?

I believe the nut "valve" on the jar controls how much fuel-air mixture goes into the engine and thus in turn regulates how fast the fuel can burn and in turn how fast the piston cycles.

Since this was build by students It took a long time. I'm guessing around 600 build hours total. I think If you have some experience with a lathe and milling machine you could probably build it in about 100 hours. Probably a good bit less when you have a CNC machine.

I made the dies.

Still a four stroke. Just valve lubrication. It used to be required during the run in period of many cars before the 60's as well.