Building an engine from scrap parts and no plans

[black85vette]

See what you think about this. You guys know how I love to re-use stuff and make things with materials I have on hand. Well here is some stuff my friend gave me. Parts his company used to make but no longer produce. The box is cast and plated. The wheels were from some sort of surgical equipment and are aluminum. I have the 2" aluminum pipe stock from my mill power feed project. I have some left over .5" x 4" aluminum for a vertical piece to hold the cylinder. HOLY COW! the scale on this is bigger than anything I have ever thought about doing. The bore would be just under 2 inches. How much air will that take??

This may not be a good idea. Anyone want to talk me out of it? (or tell me how to make it work?)

 

[Deanofid]

I'm guessing you're figuring on a horizontal with a hit 'n miss appearance, 'Vette. If so, you can sleeve the cylinder so it won't displace so much in the way of cubic inches. Don't make the stroke too long and that will help too.

If you sleeve it, you can make it a good snug press fit, then cut some fins on the OD of the cylinder to spiff it up.

About 15 years ago, I made a wobbler with a bore of about 1 1/4" and a stroke of 1 1/2". It took a lot of air. I don't mean a lot of pressure, but a lot of volume.
I have one of those larger Sears compressors on wheels. Can't remember the storage tank size, but will pump up a couple of tires before it comes on. That wobbler would have it coming on every couple of minutes. I think you're looking at a lot of air consumption if you make it with a 2" bore and any reasonable stroke to match it's size.

Dean

 

[Powder keg]

So, Have you started making chips yet? *beer* We're waiting ;D

 

[black85vette]

So, Have you started making chips yet? *beer* We're waiting ;D

No, not yet. I liked Dean's idea of fins on the cylinder. That would give it the width for a good proportion with the rest of the engine and allow a smaller bore. So I am going to have to find some appropriate material. I think I can get started cutting out a section for the crank to rotate in and also work out the bearing blocks.

 

[Bill Mc]

Hi black85vette - I appreciate what you are planning to build but, won't the teeth on those two 'flywheels' be more like a buzz saw when the engine is running? I sure wouldn't want to accidently touch them with my wrist. Just thought I would put in my two cents worth. - Billmc

 

[bearcar1]

Say BS' why not make it into a full-blown IC engine and then you would not have to worry about air volume and what not. :hDe: I can see the basics in my mind. Take your time to do some actual working sketches and I'm sure you can decide whether or not you really wish to proceed. Best of luck.

BC1
Jim

 

[black85vette]

Bill; This is just the raw materials. I plan on turning the outside of the flywheels smooth. Don't think it would look very good with the teeth either.

Jim; Good idea. That would make it much more of a project since I have not done an IC engine yet. May have to consider that. It would certainly be a one of a kind. Any special issues with an IC of that scale? How about cylinder material?

 

[Deanofid]

For IC, you will need some kind of cast iron, or at least steel liner for the cylinder.
Also, those wheels you have there look to be aluminum. They probably wouldn't be heavy enough for an IC engine. They have to provide enough momentum to provide a compression stroke. You could shrink on a steel rim.

Dean

 

[cfellows]

I've never built an air engine that has a bore larger than .75" although I have a couple of 2 cylinder engines which are .75" bore. If you get much larger than that, you are going to use a lot of air unless you have a pretty short stroke and/or run it slow.

You can make those aluminum wheels, which look like browning timing belt pulleys, into more efficient flywheels by turning off the teeth and press fitting a short section of steel pipe over the perimeter.

Looks like a fun project.

Chuck

 

[black85vette]

This project is a bit backwards. The parts are coming to me but not from a set of plans. The parts show up and then I try to figure out what to make with them.

Here is where I am right now. I have cut an opening in the rear of the base to make room for the crank to turn. Then I cut smooth flat spots for the front vertical piece and the crank supports. I turned the outside of the wheels to make them smooth and then made a close fit brass hub to reduce the opening in the center of the flywheels. I also had a new part show up. My friend gave me a cylinder from a glycol pump. The liner is already perfectly smooth and chrome plated. Next step is to figure out a vertical mount for the cylinder which will then dictate the position of the crank shaft.

 

[Omnimill]

Looking good!

Vic.

 

[CMS]

Plans from someone elses build can be nice to help guide you when you hit a tight spot, but I think you are on your way to create a custom piece, so let your own imagination go to work. And I have to agree with past posts, good potential for a hit & miss project, or maybe a half-breed. But if a steamy is in mind, go for it. Good work so far, and good luck with your creation Doc.

 

[NickG]

This will be interesting, nice work

 

[black85vette]

Not a lot done today but I do have to report a rookie mistake. I was boring out the front upright and was pretty close, took a final diameter measurement and then made the cuts. I needed .125 so I cranked in .125 instead of .0625. :wall: Fortunately I buy twice the metal I need for a part so I had enough to make another one. I did have a win though. This was the first time to use my rotary table to make a rounded part.

Got the cylinder mounted and made a couple of test bearing blocks to check the crank height. Now to make the crank, connecting rod and piston. Time to get some parts in motion.

 

[Deanofid]

It's taking on a nice shape, 'Vette. Glad you got to use your R/T. You can do lots of fun stuff with one of those things. They're magic. ; )

Have you decided for sure yet what you are going to have here? I.C., steam, air, etc.

Dean

 

[black85vette]

Have you decided for sure yet what you are going to have here? I.C., steam, air, etc.

Dean;

I think I will stick with air. With this bore / stroke it would take a lot of steam. I don't have any IC expertise. It may take a lot of air volume but thats OK if it runs. Having fun just figuring it out as I go. Still have to come up with an idea for the head and valve.

 

[Twmaster]

Hey BV...

That's pretty cool looking. Nice setup.

Speaking of buying materials... Is there a decent local metals house in the OKC/Norman area or not a too awful drive?

 

[Noitoen]

I needed .125 so I cranked in .125 instead of .0625. :wall:

My lathe, I crank 0.2 and it cuts 0.1. Maybe you should make a new graduated dial to ease with the work. :hDe:

 

[black85vette]

Speaking of buying materials... Is there a decent local metals house in the OKC/Norman area or not a too awful drive?

Yep. Metal Super Market is just off I-35 South of I-240.

 

[black85vette]

Over the weekend got a little time to work on this. Managed to make a crank, connecting rod, piston, and eccentric for the valve. Finally have some parts spinning around. Everything lined up and turned smooth. This is the first time I have used drill rod for a shaft. Really like how smooth, precise, and straight it is. Fits perfectly into the 1/4" reamed holes with a miniumum of work.

I have finally decided on the valve. I am going to mount a valve body vertically on the cylinder upright and then put a beam across to the eccentric with a pivot in the center. This will make the valve mount simple and should look pretty nice. Valve will be a simple spool valve.