Can someone who is smart (?) go over the calculation for measuring shim size to obtain correct clearances at the valves? I've read a lot of posts, and looked at vids, but apart from that bloke who says, "If they're loose....leave em the f+*k alone...", (and he doesn't really explain how you calculate a replacement shim size) I'm not sure about the actual maths of it. 

measure the actual clearance.
If too large subtract required clearance from your measurement and add that to the thickness of your already installed shim to give new shim thickness required.

If too small, subtract your measured clearance from required clearance and subtract that amount from installed shim to give required shim thickness.

Here is a excellent Excel spreadsheet which automatically calculate the thickness of the shims needed.
You have to enter the current thickness of the shim, and the gap between the shim and the camshaft.
There is even a list of part numbers for new shims.

http://forum.kforum-tech.com/members-upload/uploads/Valves-adjustment.xls

Hummm.  I can't make that link work.
Oops. My bad.  I've got it now.  Nice piece of work for those of us who like to do our own wrenching whenever possible.  Thanks!

brickrider2 wrote:Hummm.  I can't make that link work.

It works, but you have to download the file on your computer.
Then, you have to have Excel installed on your computer.
If you don't, you can download a free viewer. You will be able to enter your measurements but you cannot save the changes.

https://xlsx-viewer.en.softonic.com/?ex=DSK-1052.1