balance and stover 20" on a 6/1, left and right?

[tyssniffen]

I'm really feeling Quinn is right, that these are just plain the wrong wheels.  Luckily, I'm going to get some standards. 

I've spent a lot of time gazing into the crankshaft box, and while I don't know what weights would look like, I don't think they're in there.   I'm going to pause on the balancing game until I get some new wheels.  there's always plenty of base work to do. maybe even scrub off some rust.

now to get into the key pulling game.

thanks everyone for the input.

[cujet]

Hold on folks!! Disclaimer: I do this for a living on aircraft, helicopters, propellers, turbochargers, race engines and other spinning things. I recently balanced a Fenestron fan 3200 RPM, 4 foot diameter, with 10 blades, each one in a non symmetrical position! The listeroid balance is child's play.

First off, those flywheels will likey be fine for your application. There is no magic to balancing and some of the methods suggested are not perfect. Using a pen, for example is 100% unnecessary.

Try this, place your trial 2 pound weights opposite the crank throw. There really is no other place that you could possibly need weight. I've never seen an overbalanced Listeroid. Even with huge crank weights. (and I think you don't have a counterweighted crank, hence all the hopping)

Note: if the flywheels are not balanced well, as you suspect, the ideal position for your weight will shift by an inch or two. That's not much and likely within the noise for our purposes.

[cujet]

Once again, your finger is sensitive enough to feel vibration. "IF" you know how to position it! We do this all the time in the industry as a quick and dirty check. On high speed spinning shaft bearings.

Use your index finger. Point at your engine block and press and hold reasonably hard. With your finger/hand horizontal, like you were poking someone in the forehead and pushing them away. The listeroid camshaft area is perfect. This picks up overbalance.

Then use same finger to point down (vertical) on the ledge next to the cylinder. That picks up underbalance.

You can easily tell which vibration is stronger.

Here is what you will likely notice. The engine vibrates much more up/down than it does fore/aft.

The goal is to get both vibes even at normal RPM. At this point, you have achieved "Listeroid Perfection".

Note: I'm not saying your finger is anywhere near as sensitive as good balancing equipment. Or that you can achieve ideal Listeroid balance using just your finger. But, coupled with visual observation and general observation, you can get it as good as possible!

[38ac]

I think you are rushing into replacing those wheels myself. As said you can balance the engine with them, its just a matter of where and how much weight you need and where you put it.

To give you something to aim for.  A balance job done with nothing more fancy than a scale, a 12" long 2" shaft and a couple straight edges.
 I have been chastised previously for calling this Metro balance job smooth, call it whatever you wish. It vibrates bad enough that I estimate it would take 2-3 drywall screws to keep it from moving around if you took the wheels off the cart   
Yes. you can get here by using only  Mr X methods but plan on it taking a while because you will be chasing your tail a lot. Or you can remove the wheels,  get the offset weights equal and in the correct plane with the crankshaft and get here by starting and stopping the engine 2-3 times using the Mr X method, your choice.
6.5/1 Metro D.I.  640RPM, sitting on 4x6 Pine stringers, steel wheels on concrete floor.
[youtube]p2YwtlfAVfc[/youtube]

[xyzer]

38ac,
Does that engine have an aluminum or castiron piston.
Smooth running!
Dave

[38ac]

The Metro has an aluminum piston and that does make a slight difference in how well you can get the engine settled down. This Dursley built 6/1 engine has a cast iron piston. You will notice a little shake but look what it is sitting on, a wheeled cart barely larger than the base. I estimate at least 4 drywall screws to hold this down on a permanent  base, 


[youtube]vNJc2e6_1rU[/youtube]

[Blue]

What is a stover wheel and why is it different from a flywheel please?

Blue

[xyzer]

Remember you will have to balance them also. They might be in the ballpark you never know.

[tyssniffen]

What is a stover wheel and why is it different from a flywheel please?

Blue

the stover wheels are the heavier, yet smaller diameter wheels.  you can see from my picture in this thread (The really big photo above) how it's a full metal wheel with holes rather than a wagon-wheel-looking thing with spokes.   my stovers are 20" in diameter, the standards are a bit over 22".

[mike90045]

The Metro has an aluminum piston and that does make a slight difference in how well you can get the engine settled down.

Do All Metro 6/1 have alum piston or did you swap it ?
  (and it is possible to tell while the piston is installed ?)  (I guess I could see if a magnet will stick to the inside of the skirt)

[xyzer]

http://www.utterpower.com/lister-type-flywheel-a-matter-of-balance/
Here the issue is discussed

[38ac]

The Metro has an aluminum piston and that does make a slight difference in how well you can get the engine settled down.

Do All Metro 6/1 have alum piston or did you swap it ?
  (and it is possible to tell while the piston is installed ?)  (I guess I could see if a magnet will stick to the inside of the skirt)

Anything is possible out of India but the bulk of the time a 6HP rated engine will have  spoke flywheels and a cast iron piston.  My Metro is  direct injected and has a cavity in the piston that acts as a combustion chamber as do all D. I . engines. I have never seen a Listeroid D.I. type piston in an material other than aluminum.  Only been in to one other Metro 6/1 and it has a cast iron piston.

[mike90045]

The Metro has an aluminum piston and that does make a slight difference in how well you can get the engine settled down.

Do All Metro 6/1 have alum piston or did you swap it ?
  (and it is possible to tell while the piston is installed ?)  (I guess I could see if a magnet will stick to the inside of the skirt)

Anything is possible out of India but the bulk of the time a 6HP rated engine will have  spoke flywheels and a cast iron piston.  My Metro is  direct injected and has a cavity in the piston that acts as a combustion chamber as do all D. I . engines. I have never seen a Listeroid D.I. type piston in an material other than aluminum.  Only been in to one other Metro 6/1 and it has a cast iron piston. 

OK, I've had the head off and the piston top was flat, and I thought it was idi.    So Metro must have 2 lines in production?

[Quinnf]

There's the standard configuration that we all know and love (cast iron piston and indirect injection), and then there is a version called the GM-90, which has an aluminum piston for direct injection and counterweights on the crank throw, with balanced flywheels (like Tyssniffen's).  You can see it here:  http://trade.indiamart.com/details.mp?offer=7169682788  The head looks very different from the outside.  George had one in his shop several years ago that I got a good look at.

Quinn