Webster 4 cycle gas engine

[undersize]

Hi all,
I am currently building my first IC engine The Webster 4 cycle gas engine although my progress is slow (very) it is progressing. I am at the point of completing the flywheel and have been considering having it balanced, would this be an advantage or just an expense. I can see that the flywheel if made to drawing will be balanced by design but I am thinking the cast iron I used may not be of the best quality.
What have other builders done balance or no balance.

 

[Brian Rupnow]

That would be a total waste of money. The Webster is not a high speed engine. If you build the flywheel as per the drawing, it will be fine.---Brian

 

[undersize]

Brian,
Thank you I was not sure if any benifit would be obtained.

 

[undersize]

Incidentally what will the Webster rev to?

 

[Brian Rupnow]

with a lot of fine tuning, low end is about 850 rpm. top end is about 3000 rpm. Power band is around 2000 rpm

 

[undersize]

Thanks again Brian.

 

[Mechanicboy]

The intake valve is not ruled by cam, also it's an automatic intake valve with limited high revolution range.

 

[undersize]

Thank you for the replys I can see the performance of the engine will be restricted by its design but I was not sure if a balanced flywheel would help it when running to be smoother and not shake as I have seen of some on Utube.

 

[CFLBob]

There are many logs on building Websters around here and most people change the crankshaft instead of the flywheel.

Werowance is active now, and just got his running. He changed the shape of the end of the crankshaft to a semicircle to better balance the motion.
https://www.homemodelenginemachinist.com/threads/werowance-builds-a-webster.30772/page-7#post-324553

Brian, who commented above, has a thread on his and did a triangular sector of a circle
https://www.homemodelenginemachinist.com/threads/anybody-want-to-guess.7687/page-3#post-87083

I have a log I'm keeping up with, although I've been distracted by having to fix a bunch of other stuff around the house, and I'm using Brian's approach.
https://www.homemodelenginemachinist.com/threads/yet-another-webster-begins.31310/page-6#post-328661

 

[undersize]

CFLBob I have completed the crankshaft. I have used a similar design to that which Brian and yourself have used but I made the crankshaft in one piece. I was given a piece of stainless steel that was of the correct size to make the crankshaft in one so decided to go with it.
So the general consensus is that the adding of the balance in the web of the crankshaft is all that is needed and not to waste money or time with the flywheel balancing.
Thank you everyone.

 

[Mechanicboy]

To drill the hole in flywheel is unnecessary in the model engine since the flywheel is turned and in correct overall without oscillating/wobbling. To reduce vibration: Add weight on crankshaft to keep balanced with weight of piston/connecting rod.

In large engine can you find the drilled blindholes in the flywheel to keep balanced due the cast iron flywheel can have gas hole inside one place/not perfect dimension of the whole flywheel after casting is done then the flywheel is not in perfect balance.