Hitting the exact Compression Ratio Options

[malcolm2]

I am to the point on my rebuild that I need to make a decision. (IMG:style_emoticons/default/confused24.gif)

I am sure that this type of discussion can become very technical and fill volumes of books. I am not asking for that.

I am the kind of person that wants to know "why" a certain cam needs a certain CR. In order to make the best decision, I need answers. Or if it is a huge secret, that is fine too. I can go blindly along with the crowd.

Maybe it's really what. Has anyone experienced What an engine will do, or what will I see or feel if my cam mfg recommends 8.0:1 CR and my normal state (no shims) is 8.35:1 CR? To get to just about 8, I have calculated that I need about 2mm of deck height. I am currently sitting at 1.62mm average DH with a variance between cylinders of 0.15mm. So I need two 0.4mm shims and two 0.5mm shims and I will be dead nuts on 8:1. (IMG:style_emoticons/default/stirthepot.gif)

So the mfgr's value can be reached (if I can round up the shims), but I am curious to know how differently the engine will function if I go shim-less or even only get half way, maybe 8.2:1. (IMG:style_emoticons/default/WTF.gif)