If an engine were balanced based on flywheel weight, and you

>>16364341
The flywheel is mostly for storing energy between power strokes. A single cylinder engine wouldn't be able to run without it. Balance is a it's second job.
Most of the balancing in an engine is done by the crankshaft, that's why 4 cylinder engines have massive counterweights on the cranks.

Lightening the conrods, pistons, and crankshaft will smooth it out a bit, as will matching the weight of the pistons and conrods.

>>16364360
I4 cranks are naturally unbalanced right?
Would a "V" type crankshaft in an I4 smooth it out even more?

>>16364368
Crossplane, like a V8, you mean?

ehh, not really.
A couple things I forgot are the firing and synchronization of the pistons.

An I4 is somewhat balanced because the inner 2 and outer 2 pistons are moving in sync. And look at the firing order: 1-3-4-2. Let's call number one the 'near side'
Near outer, far inner, far outer, near inner. It's not perfect but it works well enough

If it were set up to fire in sequence (1-2-3-4) that would create a rocking motion from one end to the other, just like an inline 3 or an inline 5.

Inline sixes are well balanced because there's 3 sets of pistons, and they're all moving in opposite directions relative to the closest pair.

>>16364397
Thanks for the info anon!

>>16364410
If you stick around for a few I'll dig up some stuff so you can get into the theory of engine balance.
It's been a while so this will take a few minutes.

>>16364410
>>16364471
Well, one of them isn't around anymore, but this should help
http://www.autozine.org/technical_school/engine/smooth3.htm

>>16364502
nice, thanks

>>16364503
Whoops, I fucked up. Here's the first page of that article.

http://www.autozine.org/technical_school/engine/smooth1.htm

>>16364503
Here's the other one I was looking for.

https://web-beta.archive.org/web/20050307111523/http://www.vibratesoftware.com:80/html_help/html/Diagnosis/Engine_Speed_Related.htm