My Modified HMEM EZ Engine

[Nerdz]

Hello All! Ive been meaning to post this for quite some time, but moving stuff tends to..make everything messy. Ive been getting my work area all together, and I think I can finally (re)start on this project.

It is my second engine, and Ive contemplated dropping this one to start a whole another one! But then I would drop that one to start another and then...! However, there is another project that has my attention to (But I havent built it yet; A home energy Monitor. But anyway!

Ive decided to build this different than what the drawings show. I find the measurements to be confusing sometimes, probably because I work in a shop and they do everything from "edges", but Im able to figure it out.

The first difference you will notice is the crankshaft. Instead of having it go directly on the flywheel, I decided to make a crankshaft. Now I couldn't figure out how to do this correctly, I had but when I used a parting blade to make a offset shaft, it didnt like taking interrupted cuts. I dont have a QTP yet, so Im sure having it centered correctly would help. I decided to use two small pieces of aluminum with a brass rod in the offset position, loctited in place.



The flywheel is made the same way, but its a little thicker. It needs to be cleaned up a bit.

I also decided to make the piston/valve arrangement separate from the flywheel, Kind of like a mill Engine. I'll need to take the utmost care to align everything when it comes time for assembly.

One screw up though: The main cylinder points down slightly. I could fix this by making another mount, but Im curious to see how forgiving the engine is in terms of accuracy. The cylinder is also about 10 thou over the piston diameter. Its what I get for using a 1/2 drill bit.

I tried making the main axle last night, only to get frustrated by the 4 jaw chuck. I just couldnt get it centered :wall:.

 

[deverett]

One screw up though: The main cylinder points down slightly. I could fix this by making another mount, but Im curious to see how forgiving the engine is in terms of accuracy. The cylinder is also about 10 thou over the piston diameter. Its what I get for using a 1/2 drill bit.

I tried making the main axle last night, only to get frustrated by the 4 jaw chuck. I just couldnt get it centered :wall:.

One way of getting things lined up correctly is to clamp the two parts together, drill tapping size holes through both parts to the total depth. In this case, frame + cylinder block. Tap block and then open up the frame with the clearance drill.

10 thou seems to be rather excessive for drilling oversize. If you don't have any spare material to make a new cylinder and piston, one way out would be to machine a groove near the top of the piston and wind some teflon tape to act as a piston ring. Generally speaking, it is easier to make the cylinder bore first and then machine the piston to fit whatever size the bore comes out to.

When trying to adjust the 4 jaw chuck, work on 2 opposite jaws at a time, say 1 and 3. Get the work to run reasonably true to them and then go to the other 2 jaws. Get the work running exactly with these and then go back to the first 2 to get the job running truly all round. It may take a couple of goes, but when you have done it a few times, you will be pleasantly surprised at how quickly you can get the job running truly.

Dave
The Emerald Isle

 

[Nerdz]

When trying to adjust the 4 jaw chuck, work on 2 opposite jaws at a time, say 1 and 3. Get the work to run reasonably true to them and then go to the other 2 jaws. Get the work running exactly with these and then go back to the first 2 to get the job running truly all round. It may take a couple of goes, but when you have done it a few times, you will be pleasantly surprised at how quickly you can get the job running truly.

Dave
The Emerald Isle

Oh I did that. It was getting on my nerves after a while, but Im forcing myself to use a 4 jaw in order to do this exercise. After all, you dont learn anything if its too easy.


Got a fair amount done tonight. Its mounted on Plexy for now. I couldnt find the other wooden mount I had bought. Gremlins Took it and hid.


The flywheel crank hole is actually too big, so Ive been figuring out a way to get it to work. It seems that I'll have atleast 0.125 between where the flywheel is and the valve goes, So I made a hub.


The question is, how to accuratly attach it to the flywheel? Easy, make 3 holes. Theres one hole on the side for a set screw. I had my 3 jaw chuck lying around because its not being used, so I figured I could use this for set up. It worked quite nicely. I used a #1 Center Drill for spacing against each jaw.

Im Really Glad I bought Hertel Drill bits. I got them on sale at Enco for $33. Made in America is definitely worth its weight in gold.