Working 1/25 Engine, out of PLASTIC?

[SuperStockAndy]

Think this would be possible? I understand the cylinders wouldn't hold up, but some metal sleeves could be put in there.

What are your thoughts on this?

It depends, I might just try this Seriously.

Edited September 6, 2011 by Android

[PeterC(MrMondeo)]

TBH i dont think it would work due to pessure and tempreture , i could be wrong ,

[Scale-Master]

You can't scale the atmosphere down that small to run even if you made it out of metal. Even as a two-stroke it would be nearly impossible to get the compression and mass needed to run. Factor in plastic construction and the answer is no.

[Kaleb]

The only possible way would be electric.

[Harry P.]

Even if plastic would actually work, the size of the internal pieces needed (cam, connecting rods, etc.) would be so tiny that they couldn't possibly take any stress at all. It would never work.

[SuperStockAndy]

The only problem I see with the cam is how fast it would wear. I'd say if it was strong enough and had pretty light valve springs, it would hold up.

The connecting rods? Eh, they could be made somewhat strong.

One problem I see is that you wouldn't be able to ground the block for spark plugs.

The distributor would be a different story too...

But hey, it can't hurt to try though! Maybe I could throw a plastic rod out of the block

Edited September 6, 2011 by Android

[Scale-Master]

Those are the only problems you see right now... The more I think about it the more impossible it appears.

Even running it on compressed air would be a feat, but theoretically possible.

[MikeMc]

Reminded me of this one...no its not 1/25 or Plastic...just kool

[SuperStockAndy]

Even if it couldn't run, I imagine that it could still turn if you just turned the crank?

[Scale-Master]

The problem is not so much with the mechanical workings (although they would be very fragile at that scale) but the heat and pressure associated with combustion and compression along with certain parameters that must be preserved for combustion in any size. I won't even get into the lubrication and fuel atomization problems...

If you just want an engine that can be manually opereated or 'turned over" it removes many of the hurdles relating to an actual running engine. But it would need some compromises and concessions to even just be turned over by hand.

Can we count on you to make one now Andy? Afterall, we have simplified it for you...

[SuperStockAndy]

Dang it, you guys are gonna get me to make one aren't you?

I think I might try to make one that can be turned over, I'll have to figure out a running one

[Scale-Master]

I think you will learn a lot about how an engine works if you give this a shot.

[SuperStockAndy]

Actually, not to brag, but I know how they work.

One problem I can think of is the compression. I mean, piston rings would be almost impossible to put on a piston that size. Then if the head isn't tight enough, the compression would blow them off.

I'll be dreading making the camshaft...

[Harry P.]

It's basically impossible at 1/25 scale, even in metal. The tolerances would have to be microscopic.

[Art Anderson]

Back in the 60's, when AMT and Revell put things like V8 crankshafts in a few of their kits, a couple of guys here did work up V8's with at least moveable pistons, turn the crankshaft, the pistons moved up and down and in sync as well. They used K&S aluminum tubing for the cylinder bores IIRC.

Art

[Scale-Master]

While working features apparently are attractive to some, I prefer more accuracy over things that move just to move.

Less chance of breaking too...

[SuperStockAndy]

I remember those cranks.

Just gotta get one in my hands..

Mark, we all know that LOL

Edited September 6, 2011 by Android

[Dragracer]

Now I expect to see you do it Andy!,now Harry might remember this, in the October 2000 issue, there's a article on Charlie Ryder's '65 Chevelle Dirt Track Stock car, it's 100% scratch-built from aluminum & some other things, it has a engine that "works", it doesn't run but the pistons move with the crank & it has working gears in the rear-end & all that neat stuff!, also it's in 1/25th scale!

Edited September 6, 2011 by Dragracer

[SuperStockAndy]

Why did you suggest that Richard? Now I'll be making a running and fully operable car!

[Harry P.]

Now I expect to see you do it Andy!,now Harry might remember this, in the October 2000 issue, there's a article on Charlie Ryder's '65 Chevelle Dirt Track Stock car, it's 100% scratch-built from aluminum & some other things, it has a engine that "works", it doesn't run but the pistons move with the crank & it has working gears in the rear-end & all that neat stuff!, also it's in 1/25th scale!

I can see making a 1/25 scale engine with internal parts that move... but to make it actually run? As in internal combustion, cams moving rods that open valves. etc? Not in 1/25 scale, unless you had a few million bucks worth of incredibly precise and accurate machine tools and some sort of miracle alloy that you could create 1/25 scale cams, valves, etc. that would be strong enough to actually take the physical stresses,

[SuperStockAndy]

I got a few cents laying around, money is no problem Harry!

We got a Chevy 350 cam laying around somewhere in the garage. I imagine a 1/25 one could be made after that.

[Dragracer]

Because I know you can do it. The article is really good, I'm not into Dirt Track cars or anything really that makes turns (except on to a return road! LOL), in fact I've had the issue since 2000, & just read it a few days ago, I use the issue for reference on detailing the carburated P/M's, theres a great article by Bill Mauldin on "Building a Super Detailed Pro-Mod Engine" on page 10, to me thats the the article I read the most in that issue (besides the contest coverage!)

[SuperStockAndy]

I'm starting to wonder if it would be a good idea doing an inline-4 first....

[Scale-Master]

I can see making a 1/25 scale engine with internal parts that move... but to make it actually run? As in internal combustion, cams moving rods that open valves. etc? Not in 1/25 scale, unless you had a few million bucks worth of incredibly precise and accurate machine tools and some sort of miracle alloy that you could create 1/25 scale cams, valves, etc. that would be strong enough to actually take the physical stresses,

Even with an unlimited budget, how would you create an atmosphere a 1/25 scale engine could run in? What fuel could you use? Some things simply cannot be scaled down.

[SuperStockAndy]

Why use special fuel? I don't see why regular gas would work. The last resort could even be WD-40, but that would flood it too easy.