S&S Cycle Buret 100 ml - Manual (Page 2)

The S&S ® 100 ml buret is used to measure the combustion chamber volume of a cylinder head/piston combination. This information
can be used to determine the compression ratio of the engine. The engine builder can measure initial combustion chamber volume
and changes in the combustion chamber volume due to piston changes, valve jobs, chamber porting, cylinder height changes, cylinder
head gasket changes, cylinder head gasket surface milling and a multitude of other related modifications.
NOTE: S&S recommends using kerosene or fuel oil as the checking agent when “ccing” an engine as any remaining liquid of this type
left in the engine will not damage the internal components.
Kerosene and fuel oil are very flammable. Do not use near sparks or open flame. Use only in areas with adequate ventilation.
Procedure
1. Position the engine so the combustion chamber will fill completely. We temporarily install a spark plug and use it as a guide to tilt
the engine in the proper position before filling the chamber.
2. Fill buret to zero mark with kerosene or fuel oil.
3. Fill the combustion chamber to the bottom of the spark plug hole.
4. Record the amount of oil required to fill combustion chamber.
5. Calculate compression ratio using the following formulas:
Note - 1 cu. in. = 16.387 cc. 1cc = .06192 cu. in.
2
WARNING
Compression Ratio = (Chamber Volume) + (Cylinder Displacement)
(Chamber Volume)
Cylinder Displacement = (2 ΠR 2 ) x (Stroke)
Π = 3.142
R = Cylinder Bore
2
Stroke = Piston Travel
Use the following formula to determine the chamber volume required to achieve a desired compression
ratio in a give engine
Chamber Volume = (Displacement Volume)
(Compression Ratio #-1)
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