One of the performance options available to a Savage owner is the Wiseco High Compression forged piston.  I have seen some advertisements for the Wiseco that state a compression ratio (CR) of 10.5:1.  The stock engine has an advertised CR of 8.5:1.  So the Wiseco is supposed to increase compression by two points.

Given the Wiseco’s modest .060” pop-top, a two-point increase seems a little optimistic.  I decided to take a good look at the Wiseco to figure out exactly what the real compression ratio is.

I opted to use the on-line calculator at RB Racing.  It has inputs for the deck height along with the valve reliefs.  All I would have to manually calculate was the volume of the pop-top.

Here is a link to the RB calculator.  It is a good tool, save it.  They also have a bunch of other calculators on their site.  

https://www.rbracing-rsr.com/compstaticcalc.html

The burette.  I'm just using the hole in the cylinder to stow the burette while I'm getting ready to fill the combustion chamber.

Here is what a full combustion chamber looks like.  There is just a tiny bit of trapped air.  Not enough to be concerned about for this drill.

Next, we need to know the head gasket compressed thickness.  I have previously measured the stock head gasket thickness.  It's .028” fully compressed.

Now let’s look at the Wiseco.  The pop-top is not a full circle.  It’s .060” tall and it has a couple of circular segments lobbed off.  There are a couple of valve reliefs too.  A little more complicated.  

We need to figure out the volume of the valve reliefs.  I decided to see if I could use plumber’s putty.

Now, fill each valve relief with plumber’s putty and neatly slice off so that the putty is the same volume as the valve relief.
 
A little oil on the scale works great.

Now carefully scoop out the putty from each valve relief.  I use a little brass spatula.