Ok, I've been racking my brain for some time now about this, and for some reason it's just not making sense.

Can someone please explain to me the process behind shimming a valve. I'm sure I'm making this harder than it needs to be, or I'm just having a brain fart.

But here's what I don't get...

What's the principal behind it? How is it achieved? and what am I looking for?

Am I just looking to get the valve clearance correct?


Thanks,
it's early and I haven't had my coffee