Posted Friday, August 20, 2010 @ 04:52 PM
Here is a Link to an Online Engine Compression Calculator.
It will be usefull for quickly determining the volume and compression of a 4 cylinder engine.
Note you can use shims to adjust your compression to suit the fuel you use.
Just fill in the yellow fields and it automatically recalculates when you hit enter.
https://spreadsheets.google.com/ccc?key=0Am_PBsdamZ6gdFlPRU00WG9TMW84TEk0MHlGTmw2UEE&hl=en
The volume of the head is easily determined when off the engine by inserting the spark plugs and then using a cc calibrated syringe to fill the head with water up to the level that the cylinder mates with the head.
Just fill the syringe to the 60cc mark and slowly fill the head. Then subtract what is left in the syringe from 60cc and you will have how much water volume the head is.
You do this for each cylinder since a nicely tuned smooth engine will show less variation in head volume that 1 cc on the same head/side of the engine and not more than 2cc difference from the lowest to the highest head volume on either side.
The overall compression can be changed by adding cylinder shims to the individual cylinders equally to either increase, or if you already have shims, lower the volume and thereby change the compression of the engine to suit the gas you are burning.
Its quite easy to work on the VW engine as no sprecial tools are required and everything is easily accessible.
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