Metal Casting Zone

The bore will be 1.25" and yes, it will have a shrunk-in cast iron sleeve.

Several of us would have preferred a 1/6-scale engine because a 1/4-scale fishing boat that originally was 28 feet long will be a bit big for the back of a station wagon.

However, anything below a 1" bore doesn't run very well and normally will never sound anything like the original.

When a Hicks runs, it sounds like someone saying 'potato chip' because the choke plate is always in place but is spring loaded. So the end of every intake cycle you hear the intake 'chip' sound. To get the model to mimic the sound of the full-sized engine is one of the primary goals of the project.

Have you seen this site from a guy in Illinois. He has some of the most intructional videos I've seen and easy to watch. He makes some of his flywheels out of Hard Lead, probably printers type metal. One of the guys from BYMC put it up.
www.youtube.com/user/mrpete222

I also found my pattern for my Muller on his site.

Cores were still in the boxes, yes we used a release agent although I doubt we really needed it. The patterns and core boxes are very smooth.

Just bagged the entire assembly and flooded the bag with CO2.

The cylinder is now machined but the liner has not yet been pressed in.

Pictures a bit later.

Are you using 2% water glass now, and is that by weight or volume? Do the cores seem to be solid enough? I've wondered if it's possible for the cores to have some washout when the hot metal flows in. I guess it would depend on the gating.
Great looking project, keep us informed ont he progress.

We used 4% by weight. Way too hard I think.

I'm waiting until I get the 3D printed patterns and core boxes to do another casting although the fellow doing the wood patterns is now working on the head pattern and core boxes.

We'll switch to 2% water glass for the next casting.

One thing has been found already. The as-cast condition of the 356 alloy aluminum is too soft to machine nicely. Going to have to find out how to heat treat it. We have temperature-controlled ovens that can be programmed for time and temperature. Now we just need to find the 'formula' for heat treating.

I take it the al alloy is too gummy? Ive run into this. Ill be curios as to how the heat treating works out. Keep us updated

Hey guys! we got a keeper here! slap the chains on him and dont let him get away!!!

Took pictures of the machined cylinder today.

Obvious problems:

1. Some casting porosity but OK to use in an engine. Need to use 'real' degassing product rather than 20 year old chlorine tablets.

2. Should have waited about 2 weeks until the 356 aluminum age-hardened. Would have been a bit easier to machine. However it turned out OK.

3. Moved the head screw bores. Scale-wise, the bolt circle for the head screws would have been 1-7/8" but the full-sized engine doesn't use a liner, the cylinder is one-piece cast iron. The liner takes up space that cannot be used for head screw bores so the bolt circle moved out to 2.1". Won't be noticeable.

4. Did have one problem: One of the head screw bores passes into the water bypass bore (The Hicks factory bragged that there were no water passages through the head gasket). We'll solve that by angling the water passage bore to the side and severely down into the water jacket. So we'll plug the water passage and redrill. Loctited aluminum plugs cause no problems when this type of problem arises.

Everything looks fairly good. I did get back some reasonble quotes for 3D printing. About $70 per item, 2 patterns and 2 core boxes. So I'll order those tomorrow.

Picture is of cylinder on fixture with head fixture on top and drilling the head screw bores. Trick to machining castings is to machine a reference surface and then mount the cylinder on a fixture (on the bottom of the cylinder) to which everything can be referenced. It is then easy to bore the cylinder and machine all the bosses.

Should this thread get moved to a 'regular' area?

Here is a picture of the bottom of the cylinder.

this thread is very interesting and its very obvious that your foundry knowledge is way past basic. to my knowledge this thread cant be moved but you are welcome to end it by making a reference to another section that you would think would better suit your posts. we dont mind and are grateful for your input.

I'm moving the next posting to the Aluminum Casting Forum.