Team CAD build engine poll

[Dave Sohlstrom]

Lets take a poll of what engine we would like to convert from 2D drawings to 3D CAD parts and assemblies.

People have said that this or that engine is too complex. It is sort of like eating an elephant you just do it one bite at a time.

Most of the parts that make up an engine are very simple. There are just a couple that require working out how the part can be modeled. The block and head or heads are a couple that I can think of.

If you vote for "Other" please give an example.

Dave

 

[aonemarine]

Great idea with the poll. Keep in mind, each person is only going to be modeling a part or two not the whole thing. Then the combined efforts go into an assembly.

If the A engine is picked i have one here for reference or pictures. Its assembled and in the car running, so no shots of the internals. But i do have a couple of extra rods laying around. Also have a load of 8ba flattys disassembled.

 

[Dave Sohlstrom]

The other thing to remember is there are not that many parts to an engine just multiples of most of the parts.
So model 1 piston, 1 con rod, 1 wrest pin etc.

Dave

 

[Flat32]

I recently completed in Solidworks the engine block true to Ford blueprints. Having 3D prints made by Shapeways scaled to 16% in acrylic. 1946 to 1948 59 block.

Found out they offer different materials including brass and bronze. I thought it would be in some kind of faux material simulating the real metal, but it turns out they print in investment wax and cast the part. Quite expensive, but there's no other way to get a true to scale block that could be used to make a running engine. 1/4 scale would be a logical choice. With some details deviating from true scale 1/5 could be possible.

I've been a toolmaker, but "discovered" CNC and make parts for my full sized Flathead, patterns, core boxes, castings and finished intake manifolds and heads.

I am not a model engine builder, too old to become one, but would be willing to share my CAD files with a serious builder willing to tackle a true scale Flathead.



Flat32

 

[Dave Sohlstrom]

Flat32

I clicked on the render you attached here and got forwarded to your photobucket. Looked at more pictures of the CAD models very impressive work. I would not even want to know what Shapways would charge for a bronze casting of the block in 1/4 scale. I have a friend in England that does lost wax castings for model locomotives and when talking to him once he was saying that there is an investment tht will handle the temps of cast iron.
I don't know if the block could be cast using ceramic shell with how small the water passages are.

I would be interested in getting a SLDPRT file of just the block that I could open in SW just to see what you had to go through to model it.

I am taking paper drawings of a holt 75 engine and converting to CAD. Finding several errors in the paper drawings.

Dave

 

[Flat32]

I'm in Federal Way Washington, retired and always home so if you're ever up my way you're welcome to stop by my place.

I'm going to make a set of core boxes to make cores the way Ford did and attempt to cast the block in some low temp metal. I was surprised at how thin bronze can be cast, but don't have any investment casting experience. Making cores and molds, external cores essentially, bypasses the wax investment entirely.

Flat32

 

[aonemarine]

Flat 32, could you slice the block in half thru the mains and send it to me? I would like to try printing it out and then investment casting it using the lost pla method, or maybe lost wax if I can get it to print ok in the machinable wax filament.

 

[Flat32]

As it is turning out the 3D printing methods that can print this block are very limited. Impossible to do this with a filament printer even at 1/4 scale.

I'm investigating what printer can and hoping would be under $50,000.

Flat32

 

[Dave Sohlstrom]

Depending on the size of the wax. Have you upload a STL file to shapeways to see if they can print it for you. They do print in wax but the bounding box size is limited.

Dave

 

[Flat32]

Dave, the block is not one file, but nine or ten. Split up because my Solidworks 2005 becomes painfully slow when the file gets around 40MB. Even split up the complexities of the part make the design tree cumbersome. I even have difficulty keeping track of how I created the files.

Flat32:wall:

 

[Dave Sohlstrom]

Would you mind sharing your SW part files with me. I have SW 2014 and would like to study how you are going about things. PM being sent.

Dave

PS We have a daughter and a son in Kent.

 

[aonemarine]

As it is turning out the 3D printing methods that can print this block are very limited. Impossible to do this with a filament printer even at 1/4 scale.

I'm investigating what printer can and hoping would be under $50,000.

Flat32

I am fairly certain I could print it, although I do quesition how well I could cast it. Im not sure if my cad program will let me make many changes to the assembly, thats why I asked it to be split. Maybe I could do something with it as an stl file but that would be pretty limited as well. I would still like a look at the file to see if it would be possible (one way or another) but my cad skills and cad program arent exactly top notch...
Here is a SBC I printed out from grabcad.com It didnt come out too bad, but not well enough for me to waste the time and money on casting. If I could split up the file to get a slightly better print then I would cast it.
things like removing the cylinder liners and head bolt holes would make it more printer and casting friendly....



Block was printed with the pan rail down and is complete with cylinder sleeves, cooling passages, and oil galleys. Printed on an extrusion based machine (Rostock max)

 

[aonemarine]

Another option would be machining pieces from wax then building the assembly in wax for casting.

 

[Flat32]

I'm a fanatic for detail resolution. Filament just can't satisfy my need.

Looking at an Objet30 Pro which will have to print my parts before I buy.

Shapeways took three tries before they got my last part done and shipped.

Didn't receive it yet.

Flat32:fan:

 

[Dave Sohlstrom]

Not an IC engine but here is a video of the first run of the W T Preston that mike Jones (hookpilot) over at RC groups scale boats forum built and I designed and built the engines. I have some small details to go.

Dave


https://youtu.be/mdYq6gO8QZY

 

[aonemarine]

I'm a fanatic for detail resolution. Filament just can't satisfy my need.

Looking at an Objet30 Pro which will have to print my parts before I buy.

Shapeways took three tries before they got my last part done and shipped.

Didn't receive it yet.

Flat32:fan:

And how much resolution does a casting need?? Good luck with whatever it is you are looking for.

 

[Flat32]

I'll make metal castings using plaster cores made in core boxes that are cast from 3D printed patterns which will have some relatively deep ribs in places. Detail can suffer with the multiple steps as well as dimensional accuracy.

The actual block has many walls at a nominal .180" thickness and the exhaust ports go through the water jackets. I couldn't tell from the pic, but it appears the green block doesn't have water jackets.

I will be making fine scale models in printed plastic that shouldn't require any hand finishing of surfaces.

I will be making transparent plastic models and transparency is directly related to surface finish inside and out. I want to be able to see the internal ports through external water jacket walls which will be .030 thick.

Shapeways took three tries on a very sophisticated printer to get my last part done.

I have a Solidscape Modelmaker 2 that was designed for printing wax models for jewelry and dental crown use. I have to get it running to see if it can print a 1/4 scale block, but it's doubtful the investment plaster would survive burnout.

Flat32

 

[aonemarine]

I couldn't tell from the pic, but it appears the green block doesn't have water jackets.

Block was printed with the pan rail down and is complete with cylinder sleeves, cooling passages, and oil galleys. Printed on an extrusion based machine (Rostock max)

but it's doubtful the investment plaster would survive burnout.

Why is that? I directly investment cast pla plastic from extrusion based printers all the time and have good luck doing it. Ive also investment cast plastic parts from sls nylon that works out very well also. The small cores for the exhaust ports could prove challanging using plastic patterns as the thermal expansion is quite high and may break the cores, but in wax it really should not be much of a challenge at all. One thing to keep in mind, you would be making a casting not a finished part. So adding material to areas that would be machined back down to tolerance needs to be considered.

 

[Flat32]

OK Aonemarine. Email me your email address and I'll set a shared Dropbox and put some files in it.

Do you do vacuum assisted casting?

Flat32

 

[aonemarine]

Yes, i use vacuum assist and wow what a difference it makes i used to just do straight gravity pours. They work out ok with heavy materials like bronze, but aluminum really suffered. Using vacuum assist has been the biggest improvement with the surface finish of the castings.