are these values from sequential parts? are they in time sequence or are they randomly selected from a lot?
How many change points are included? (by change points I mean different setups of the equipment, raw material lots, operators, etc.)
what is your specification?
Are you trying to calculate a Cpk value? if so why? is it a Customer requirement or do you want to understand the defect rate /yield of the process?
The data is 'chunky', meaning that there are only a few values that actually occur - this will overinflate your standard deviation and make any Cpk calculation useless. not to mention the non-normality of the data. If you can answer the above questions we can give you a useful approach to understanding your capability. *I* never transform data...there are many useful ways to deal effectively with non-normal data and transforming data tends to enable you to miss the really important things about it...