venomxx

I'm thinking of casting a twin engine block. Anyone dare to venture that way ? lol

tim220225

My Feedback: (4)

Seems to me as though you would have much more work for no gain. You need a pattern of some sort. The "easiest" way I have seen is foam. I have seen a Chevy Vortec block done this way. To look at the foam you would have thought it was the real deal. Pour or inject the molten metal in and the foam goes away. When cooled you have a block ready to machine. Why not just machine it out of a block of metal either manually or CNC? Either way you have to machine it. With the casting you need to machine it twice. Once for the mold and again for the finished product. Plus you have to deal with a foundry furnace and the mold processes. May even weigh more than a machined case. Some day I would like to machine a whole case. Need to retire first so I have all the time I need.

captinjohn

One good aspect of making the mold....once you got a good mold you can make (pour) several more and even sell the blocks to other twin engine builders. Capt,n[:-]

ROOSTERLEW

maybe one of you could come up with a drawing, or better yet solid model of a case I could write a program for CNC and they would be very easily duplicated

tim220225

My Feedback: (4)

Yea that would be the ticket. But then I would need to retrofit the Bridgeport to CNC. Man it would be sweet though. Just Us Machine in Sterling Colorado used to do BME's cases. I talked to him about doing some for the 61cc Echo twins I have. Cases would be about $250.00 each for a very short run. Once you have the programming it is just a matter of setting up the tooling and then stand back and watch it hum.

Laird SS

If you had a solid model (Solidworks for example), you could use readily available software (Mastercam possibly) to create the CNC code for the machining and use the program to proof the code before ever cutting any metal.

venomxx

It would be a 4axis milling cnc isn't it ? ...hmmm Casting wouldn't be so bad since we can use the regular cylinder head. The casting would just be the base engine.

tstotts

Tim sounded to me like Rooster was offering the program if someone furnished the drawing or working plan. Would that cut down on the cost of getting a case machined?

tim220225

My Feedback: (4)

Troy in a perfect world it would cut down the cost. However I bet most machine shops would want to write their own program. At least they would review all aspects of the program.

tstotts

What I know about CNC you can stick in a thimble. LOL But always looking for away to get something for nothing. thinking about making a twin out of 2 echo 2100s.

Ralphbf

My Feedback: (27)

Try this link:

http://www.rcuniverse.com/forum/m_54..._1/key_/tm.htm

Huey pilot may still have an extra block.

av8tor1977

My Feedback: (6)

Hey, go for it and cast a block. The idea has fascinated me for some time, but I have no experience in that field.

AV8TOR

venomxx

I am going to cast one this weekend.

av8tor1977

My Feedback: (6)

Pics, info, keep me/us posted please!!

Good luck,
AV8TOR

Ralphbf

My Feedback: (27)

So what are you going to cast?

av8tor1977

My Feedback: (6)

So how did your casting project go???

AV8TOR

hollbrow

The way I see it, casting/machining a block is not that hard an endeavor- I have machined single cylinder engine blocks to fit an existing rotating assembly with nothing more than my cheap little import lathe, mill and a boring head. It can be done- plan to spend ALOT of time standing there making chips. The problem lies in the crankshaft for whatever you are building- getting a double throw crank put together that will stand up to the situation is much harder than the casing to put it in. Most of the "model engine" sites that give any details on how they make cranks are geared towards the folks who make multi-cylinder model engines just to run them on a stand- not put it in a plane and turn it 8,000 rpm.

If I could figure out how to accomplish this, I'd build me up a twin based on Echo cylinders/pistons rods.
Anyone got any ideas?

Ralphbf

My Feedback: (27)

http://www.rcuniverse.com/forum/m_54..._1/key_/tm.htm

And a video http://rcuvideos.com/item/N8BCJ2L4KXVQH2FS

I ran out of gas at the end of the video.

aero nut

Hey ralph is this engine running on gas/glow?

Ralphbf

My Feedback: (27)

Yes it is.

You can see the glow stuff flapping in the breeze.
It has a Sullivan dual glow set up and a lead acid single cell battery powering it.

BillS

In the 70's I owned a Yamaha motorcycle dealership and we rebuilt cranks for singles an twins. At that time a twin crank was simply two single crank assemblies splined together. The two inside flywheels were splined and a light press fit. A Lambreth seal (also used in steam turbines) was used to prevent cross flow between cylinders. The case was split horizontally. In the 70's individual crank parts could be purchased. The inside spline would be the difficult part to machine.

A trip to the motorcycle shop might produce many ideas.

Bill

av8tor1977

My Feedback: (6)

Haven't you seen the pictures of my twin running on Gas/Glow aeronut?

AV8TOR

Ralphbf

My Feedback: (27)

I think it's just that mine is prettier.

captinjohn

I think you guys should post more photos or a vidio of a glow/gas running!!! Capt,n

hollbrow

I have also seen the way some motorcycle cranks are done- alot of times, the crank throws are just a serious pressed fit together- I just can't see acheiving the needed accuracy like that without some major investment in tools and know how- also, this is one of those cases where the small size of what we are working on makes it harder also. The idea I saw in a post on the spot welding together of the counterweights sounds do-able. I will have to look into that.

I want to focus my attention on the smaller ones- like made from 23cc echo parts- I have a box full of old 23cc echo stuff from commercial trimmers. They are high quality parts.

Plus, I don't think my boring head will go big enough to do a case for the G-62's.