Need engine for Inboard drive - DIY?

[mgriffin]

Does anyone like the type of motor that is low RPM, crank start? (Like this: http://www.youtube.com/watch?v=CH912...ature=related). If not, then you must like the annoying noise of high rpm low CC motor. How could you? these low rpm high cc engines are more efficient and last longer. I am on budget of 300 dollars, and after I build my small boat, I will have 200 dollars left. I need an engine like the one in the video, but a little smaller, about half that size or less for my boat. Enjoy the video!

[mgriffin]

No matter what it takes, I NEED A MOTOR FOR MY BOAT. Even if I have to build it. This is my idea for building it.
The engine consists of a steel box 5.25 inches tall and 2.5 inches wide. The walls are .25 inches thick. Overall the engine is 5.5 inches tall WITH the base and the head cover, which are both 1/8 inches thick. If you are looking at the top of the engine, you will see a 2.5 inch square with a screw in each corner. If you turned it upside down, it would be a 2.5 inch steel square. The cylinder has 1/4 inch thick walls, and a 1 inch bore and a 1.5 inch stroke, overall it is 1.5 inches outer diameter. The CC is 19.3055. The connecting rod length is 2.75 inches. The flywheel has a diameter of 3.5 inches and a shaft hole of 1/2 an inch. The crankshaft/driveshaft has a diameter of 1/2 an inch. the cylinder is connected to the the metal box via a 2 inch metal square 1/4 inch thick with a 1 inch circle cut out of it to allow the connecting rod to pass through. The 2 inch square mentioned before is welded inside of the metal box 2.25 inches from the top after the cylinder is welded to the square. The exhaust port is .5 an inch. The space between the cylinder and the metal box will be filled with water AFTER the it is coated with a rustproofer. The top of the cylinder is level with the top of the metal box, and the head cover covers the water jacket and the head of the cylinder. That is all of the information that I am going to give you because if I told you EVERY single detail, such as the fact I am going to paint it green, then you would get bored and not read all of this. The links: Cylinder:http://www.discountsteel.com/index.c.../itemID/44.htm Piston:http://www.discountsteel.com/index.c...itemID/113.htm Case:http://www.discountsteel.com/index.c.../itemID/30.htm Head and Base:http://www.discountsteel.com/index.c.../itemID/35.htm
These are the MATERIALS that I am going to use to build it. Please tell me if this motor will work

[mgriffin]

Even if none of you reply I'm going to build it still. It's going to be splash lubrication by the way. You will notice that each link has a part before it, so what is on that link is what I'm going to use for that part.

[hoytedow]

That Lister diesel was pretty nice. Are the Chinese building them?

[mgriffin]

Probably, knowing them...My dad is thinking of buying one for a generator set, a 6 horse http://cgi.ebay.com/Metro-Lister-CS-...d=p3286.c0.m14

[marshmat]

Hi Michael,

Possible? Maybe. I have only two pieces of advice regarding this particular project:
1) Be careful,
2) Don't get too optimistic about efficiency or longevity.

[mgriffin]

Hahah ok. Thanks!!!!
You have helped me alot!!!

[mgriffin]

Inlet system: High Pressure check valve?
(One that lets fuel in when the piston
sucks on it?) Would that work? The check
valve would let fuel in, then after the piston
is through with it's downward stroke, and the
exhaust port lets air in, and the upward
stroke begins, compression should ignite
it. Would I need a glow plug to start it?

[mgriffin]

Oh yeah, I decided to make the piston out of brass and the case out of galvanized steel. Both of those are cheaper. It's still going to cost 70 dollars though!!! I would estimate it's weight to be around 30 pounds, even if it is 5.5 inches tall and 2.5 inches wide!! Oh yes, I'm going to paint it green

[marshmat]

Michael,

Do you have the machine shop equipment and skills necessary to turn these chunks of metal into a working engine?

If you do, then you probably already know just how tedious and complex a job this could be. And you probably also know that a skilled machinist ought to be making enough money to afford a small engine.

If you don't, then you're going to get very frustrated very quickly once you start trying to put things together. Example: Brass has a higher CTE than steel, thus a brass piston in a steel cylinder is likely to experience one of two conditions: if it fits properly when cold, it'll seize when hot; or if it fits when hot, it'll shrink when cold.

[srimes]

It's clear from your questions you do not currently have the skills to build a durable engine. Especially concerning the valve train. I'd suggest buying an engine, and maybe modifying it to suite. Many engines can be detuned to run at a lower RPM with a different cam (and maybe an intake). You might need a larger flywheel too.

[mgriffin]

OK, then I make the piston out of the same material. And "These chunks of metal" only need to be cut, drilled, and welded. Everything is pretty much ready to be drilled, cut, and welded. The biggest drill hole I need to drill is 1/2 an inch. The hardest cut is a 1" circle out of a steel plate. All the rest is straight cuts and easy welds and drill jobs. If it doesn't work as internal combustion, then all I need to do is convert it to Co2. I might have to do a little work, so what? I'm not afraid of work. My dad has a welder, a cordless drill, and a grinder to cut steel with. I don't have to do any precision machining, just drill it, cut it, then weld it together. The exhaust port in the cylinder might need to be smoothed down after it is drilled. How am I going to drill the holes for the crankshaft? Easy. A steady hand. I'm going to practice on some scrap before I start this. Why can't I build an engine with simple tools?

[mgriffin]

How am I going to cut a 1" circle with a grinder?! I'm not! I'm going to use a jigsaw.
I didn't mention the valve train. I'm sorry for the confusion, but I'm going to use a check valve for the "valve train". When the piston sucks on the check valve, fuel is let in. After the cylinder moves down to the exhaust port and sucks air in, then it moves back up and the compression ignites the fuel. If you don't believe that will work, then I'm going to use a glow plug to ignite the fuel during starting. After that, it just uses compression ignition.

[srimes]

I don't want to get in to a pointless argument. I DO think it CAN be done. From your posts I don't think you have the knowledge and skill, but if you're determined to learn it's possible. It would probably take years for you to actually build a working engine. If you do make it I'd love to see pics and read your report.

Sounds like you're describing a bastardized 2-stroke gas engine that will "diesel." That would run poorly if it all as far as I can tell.

How will the piston seal in the bore? What kind of bearings will you use and how will you line them up? What kind of check valve are you going to use? Will it stand up to the pressure and how many cycles is it expected to last? Do you have any idea how to answer these questions?

[Guest625101138]

Here is modern music:
http://www.youtube.com/watch?v=zg9-APfZ5Tw
Enjoy.

A little more power than the Lister. Full torque at zero rpm so no crank. Just brilliant. China are ditching the lumbering iron mongery in favour of this stuff. Requires a fraction of the energy to achieve the same result because there is no need to lumber all those heavy castings around the place.

Rick W