Bollaero 18

[eartaker]

So for the past week I have been working on the Bollaero 1.8.... everyone has to start somewhere right?

More pics of the build.....Little Engine - Exploded??? - Pirates of The Cyber World

Link to site and plans....BollAero 1.8 Gallery

[stevehuckss396]

So for the past week I have been working on the Bollaero 1.8.... everyone has to start somewhere right?

And a good start it is. Nice work so far!!

[dynosor]

Hi Eartaker

What metal are your engine parts made from? They appear to all be aluminum; or is the crankshaft and cylinder steel? If AL only, you may have a galling problem when you run it.

[eartaker]

Everything is made from 7075 T6 aluminum except for the crank and piston wrest pin. The crank is steel. I thought the same thing.

[dynosor]

Everything is made from 7075 T6 aluminum except for the crank and piston wrest pin. The crank is steel. I thought the same thing.

Thanks. So is the cylinder wall lined with steel, plated with nickel or bare aluminum?

[eartaker]

Just bare aluminum...

[paulsv]

Just bare aluminum...

I just took a quick look at the plans online, and I am going to print them and study them a bit. The online plans call for a cast iron piston and counter piston, and 12L14 for the cylinder.

Neat plans! I look forward to following this build!

[eartaker]

paulsv,

It did call for a steel sleeve but I have a hell of a time trying to get a steel bore smooth for some reason. I tried to start my engine today... FAILURE... My piston is to leaky and I don't have enough compression.... Also the fuel has me scratching my head.... I have tried many blends.

Anyone have a known fuel mix that they know works?

[eartaker]

Made a new piston and compression piston... much more compression now but still cant get the engine to run.... Tried a oil,gas,ether mix of 33% and a little bit of Amesoil cetane boost but no luck.... could crank down on the compression a little, need a 100% known fuel mix.

[dynosor]

I once made fuel for a model diesel engine that worked. It was 50% kerosene, 25% ether & 25% lubricating oil.

To start you had to run rich at lower compression and then lean out as you increased the compression.

As fluid is incompressible you have to balance the amount of fuel in the combustion chamber with the space limiting adjustable piston.

This was on a small commercial model two stroke diesel that used a carburetor, but no glow plug, just variable compression.

[eartaker]

Hmmm I will give that mix a try tomorrow... I got it to fire ONCE....

[paulsv]

Made a new piston and compression piston... much more compression now but still cant get the engine to run.... Tried a oil,gas,ether mix of 33% and a little bit of Amesoil cetane boost but no luck.... could crank down on the compression a little, need a 100% known fuel mix.

You might want to read through the FAQ on this site- (Under the "Resources" tab in the left column)

Ron's Model Engineering and Model IC Engines Index

there are several questions and answers that deal with fuel mixture, how to obtain ethyl ether, etc. The classic mix is equal parts mix of kerosene, castor oil and ethyl ether. There used to be a place in California that sold it over the web, and there is a link in the FAQ to that seller, but it looks like the website is being re-done.

As for the finish on the steel cylinder, the commonly recommended procedure is to start by drilling, then boring, to get the axis of the bore aligned, then reaming the last .010 or so, and finally lapping with diamond paste. The same lapping is done to the piston. 12L14 is pretty easy to get a smooth finish on. Some other steels, not so much.