Proposal to design a "First Build" engine

[rleete]

I haven't made anything yet where I can use lung power.

Really? My rocker runs on lung power quite well. I can even get some pretty decent revs out of it if I push a little.

Works so well, I made a couple out of PVC (body) and aluminum (piston) for neighborhood kids. Instead of a base, I made the cylinder extra long - about 3" - so it's hand held.

 

[Lykle]

OK, here is an overview of the Metric version.

Sorry couldn't resist.

In making this I noticed a few measurements missing in the drawings.
I managed to deduce them, so I think it was intentional. As in the hidden error?

Just to be sure, the dimensions I missed were:
Diameter flywheel.
Diameter crankshaft
Diameter of the thinner part of the valve
Length of both the con rods

I will produce the metric drawings tomorrow, if you don't mind.

Lykle

 

[black85vette]

Just to be sure, the dimensions I missed were:
Diameter flywheel.
Diameter crankshaft
Diameter of the thinner part of the valve
Length of both the con rods

Awesome job on the 3D drawing.

About the "missing" measurements; Those were going to be part of the write up because they are not really critical. Flywheel can be 2.5" to 3" diameter and 1/4 to 7/16" thick depending on preference or material available. Crankshaft should be 1/4" and I'll add that to the drawings. Thinner part of the valve is around 1/8" but not critical at all. Length of the connecting rods was not called out because I planned on doing it "functionally".

1. Connect the piston to one end of the connecting rod.
2. Set the piston to 1/16" inch before TDC
3. Set the crank so it is at its closest point to the cylinder
4. Mark and drill the hole for the crank end of the connecting rod.

Valve is similar but I put it to the full open-intake position and the flywheel pin to the side away from the valve.

Doing it this way eliminates accumulated small errors in the build. Not a purist approach but this is for beginners with limited experience and equipment. So hopefully there were no intentional hidden errors like we had suggested early on. ;D However I cannot rule out my pitiful memory for having overlooked or forgotten something either.

I had thought we were going to want a metric version but just had not got to that point yet. So thanks for jumping in and joining the party. It will be great to have this in metric. Appreciate you taking it on. :bow:

 

[va4ngo]

Good work Lykle and Vette. Thans for removing the responsibility of a deliberate error from my charge.

Metric is good for those in metricated areas. Like the idea of functional build as you go for beginners and those of us who may occasionally need and use this method.


Cheers
Phil

 

[Deanofid]

OK, here is an overview of the Metric version.

What? Are you some kind of troublemaker?

In making this I noticed a few measurements missing in the drawings.
I managed to deduce them....
Lykle

Oh... So now we're Sherlock Holmes.


(Sorry, couldn't resist.)

Nice computer drawing there.

Dean

 

[Lykle]

Trouble maker, me, no never! 8)

Anyway, here are the drawings for the Metric version.
Took a little longer then expected, sorry.

Let me know what you think. (as if you would never do that)

Lykle

edit: Modified the BOM

View attachment EZ engine.zip

 

[black85vette]

Great job on the drawings! I'll steal some ideas from you on how to layout the drawings. I am just getting them finalized now and redrawing them in a new software package so I have a slight learning curve as I go.

Thanks for your contribution. I sure the metricated folks will appreciate it.

 

[black85vette]

Just got back from our fall foliage trip. Took the laptop and got the drawings cleaned up for the U.S. version. After we document a build and get the instructions together I will upload them all in one folder in the upload section. For now here are the drawings in pdf format. Let me know if you see any errors.


EDIT: Drawings updated 10/30/09, 11/12/09, 11/13/09

View attachment EZ Plans US 13NOV09.zip

 

[gbritnell]

Hi Black85vette, Please accept this as helpful advice. When I was taught drawing, when I taught drawing and when I draw the first question that needs to be answered by the designer/draftsman is, could I build it from my drawings. Your view layouts should conform to drafting standards which makes it easier for the reader to understand what he's looking at. You have for example a dimension for the valve which should be spelled out as a diameter, not just a dimension. The reader has to infer that the cross section is round and not square. These might seem trivial to you but you have in your mind what you want, the reader doesn't. Once again please take this as constructive advice.
gbritnell

 

[black85vette]

Hi Black85vette, Please accept this as helpful advice. gbritnell

Of course I will take it that way. It would take quite a bit to offend me since my total training in drafting was sitting at a table with a square and set of triangles in Jr. High. :big: I use some CAD at work but mostly because I work with new building construction, not machine drawings.

I can change that to a diameter reference without a problem. I am hoping that some of this can be figured out by looking at the pictures but the clearer the drawings are the better for the builder.

I am also open to a real pro putting these into "drafting standards". (hint, hint)

Tnx for the feedback.

 

[gbritnell]

Hi Black85vette, If you look at the set that Lykle posted they are excellent drawings, the arrangement, dimensioning etc.
gbritnell

 

[black85vette]

Starting the build part of the project with the intent of compiling a build document with all the drawings, notes and photos in one place.

A note on measurements. Every measurement on this is given in decimal inches but if you do the math you will find that almost all of them are some multiple of 1/16th inch. You can layout most of this with a square marked in 16ths.

First cut the two pieces for the frame from the 1/4"x2" aluminum. Both pieces are 4.5 inches long. Layout the location of the holes. I use layout dye but a large magic marker works fine. Use your calipers to scribe lines both horizontally and vertically. A machinist's square and scribe could be used here also. Center punch each of the hole locations including the hole in the top for the bushing set screw and the two holes in the bottom edge for the screws to attach the base. The air passage is 1/8th inch. All the other holes are tapped for a 4-40 screw. A 4-40 thread calls for a .089 drill bit. In aluminum I prefer to use a 3/32nds inch bit which is .094. It makes tapping a lot easier. Mark and drill the 1/8th inch holes in the base. For the .375 (3/8ths) inch hole, you should first drill it with the 1/8th inch bit. The two holes in the bottom should be about 3/8ths of an inch deep.

To aid in tapping make a simple guide by using a piece of scrap round stock. Put it in the lathe and using your tail stock chuck, drill a hole large enough for the shank on the tap. Doing it in the lathe helps assure that the hole is centered and square. Hold the guide firmly in place with one hand and start the tap with the other. Do the same thing for the holes in the edge by clamping the piece in a vise flush with the top and then use the vise as a wider base to help keep the tap perpendicular to the work.

 

[black85vette]

Now you have the frame of the engine ready. Put it together with a couple of screws. If you ordered all of your screws 1" long you will need to cut these down to about 1/2 inch. Cut them to a length that will not bottom out in the hole. Look at the picture below. It is a scrap piece of 1/8th inch steel strap held in the vise. Drill and tap it to 4-40. Put the screw in and then cut it off. When you remove the screw the steel piece will clean up the threads for you. If you are using a hacksaw put a nut on the screw on the same side as the head of the screw. Tighten the nut down when you have the screw where you want it and the screw will not rotate when you cut.

 

[black85vette]

Time to make the valve and cylinder bodies. Cut the 3/4 inch square stock to 1.625" and 1.875". My preference is to drill the large holes first so that if something goes wrong I don't have to redo all the other holes. Layout the center for the valve, center punch it and then drill it with a 7/32 drill all the way through. Be sure the piece is vertical on both sides. Drop your drill down next to it and verify that it is parallel to the body before drilling. Then switch to a 1/4 inch reamer and finish the hole to size. Use plenty of oil when cutting and pull the reamer out often to clean the cuttings off of it. Now you can drill the 1/8th through holes and the two air vents. Since the air vents will penetrate into the hole you just reamed you will need to run the reamer down it again to clean up any burrs. You can do this by hand. Hold the piece in one hand and turn the drill chuck with the other. Turn it just long enough that the reamer turns freely.

The cylinder is done much the same way except the cylinder hole is 1.375 inches deep. Put a piece of tape around your drill bit so you know when to stop. Drill the hole with a 1/4" bit first then a 15/32". Finish it off with a 1/2 inch reamer. Mark, center punch and drill the 1/8th inch mounting holes and air vent. Check to see that the air vent is fully open into the cylinder.

 

[black85vette]

Mount the valve body and cylinder to the upright part of the frame with 1" screws. That takes care of the chassis. Next will be making some round parts on the lathe.


NOTE: If anyone has any comments, corrections, tips, hints, criticism or otherwise useful information now is the time to contribute. Anything added will be compiled into a final document on building this engine and then packaged as a .pdf in the upload section when we are done.

 

[black85vette]

Updated the drawing to show the cross section of the piston and valve and included diameter measurements. I replaced the folder in the original post rather than take up more space.

 

[black85vette]

Turn the piston from brass .5 inch round stock. Turn the .250 inch part so that it is .4375 inch long. The piston body is .5 inch long. Mark it and using a parting tool cut it off. Put the .250” end in the chuck and using a file and some fine grit emery paper smooth the piston and fit it to the cylinder. Stop and check fit often and wipe the piston clean. You want the piston to move freely in the cylinder with lubricant. It does not need the compression of a combustion engine so a little loose is OK.

 

[black85vette]

The valve is made of .250 steel stock but you could make it from brass also. Cut it at least 1 inch longer than the valve needs to be so you will have something for the chuck to hold on to. I like to make the initial cuts with the parting tool to the depth needed. Mark the first cut, position the parting tool, zero the cross slide and then make a cut .0625 inch deep. Remember the cut is measuring depth on one side so it is like a radius. A .0625 deep cut will reduce the diameter by .1250 inch. That will be a good size for the smaller diameter part. Move the work piece out for the second cut.

Three points:
1. Rotate the chuck by hand to be sure you will not hit the carriage or anything else
2. Keep the cut as close to the chuck as you can
3. Use a low speed for a parting tool and feed slowly

Do the same thing for the next small diameter. Finally remove the work from the chuck and file / mill / grind the flat spot for the connecting rod. Also, go ahead and drill / tap the 4-40 hole for the connecting rod. Put the end of the valve back in the chuck so you can file and sand it to size. As with the piston check the fit often until you have smooth action back and forth.

Grind the flat, drill / tap the hole and fit to the body before you cut the valve free from the parent piece. This allows you to hold or clamp using the end that will be cut away and discarded and not mess up the valve pieces.

 

[black85vette]

The flywheel can be made of .250 inch aluminum flat stock. Punch a center mark and then scribe a line to draw a 3 inch diameter circle. While you are doing this scribe a line .250 out from the center and make a punch mark anywhere on that radius. It will be used for the pivot point for the connecting rod to the valve. It is easier to do this now than when you have drilled the center hole for the shaft. Using a bandsaw or hacksaw cut close to the line and remove as many corners as possible. Center drill the punch mark you made and using a live center push the flywheel up against the chuck jaws. Have the chuck jaws set to less than the diameter of the flywheel. You can use double sided tape if you like to help turn the flywheel. Do not over tighten the live center as it will flex the aluminum plate. Making light cuts reduce the diameter of the flywheel until it is smooth all the way around. Now you can mount the flywheel in the chuck using pieces of soda cans cut into strips to protect it from the jaws of the chuck. Drill the center of the flywheel with at 15/32nds drill and follow it with a .025 inch reamer. Take the flywheel out and drill / tap the punch mark you made for a 4-40 screw.


Almost done! Now some small pieces and the connecting rods. Then ready to do the timing and see if it runs.

 

[black85vette]

The shaft for the engine is a 1.125 inch piece of .250 steel rod. Polish it with fine emery paper and check its fit through the bushing to be sure it rotates freely. Glue one end of the shaft into the flywheel with epoxy glue.

The crank is not critical and you can make it any shape. It just needs a .250 hole and another hole .375 inch from it drilled and tapped for a 4-40 screw that will be its pivot point for the connecting rod.

You will need to make a connecting rod for the valve to the flywheel pivot. Here is the functional way to do it: Insert the valve and then stick a drill in the air vent with the piston / cylinder removed. Push the valve in until the piston just touches the drill. This is the “open” position and the valve needs to be completely clear of the air vent during the power stroke. At this time the flywheel pivot point is at its furthest point away from the valve assembly. With the valve just past the hole, position the flywheel and measure the distance between the holes and then use that distance to make a connecting rod. Use .250 x .063 brass strips and cut them .125 longer on each end than the center of the hole. Place a .063 thick washer behind the connecting rod on the flywheel end only. This will give it some clearance so it won’t rub on the flywheel.

Do almost the same thing for the piston except position the piston .063 inch before it hits the bottom of the cylinder and put the crank pivot towards the piston. Measure and make a connecting rod for that side also.