turn the crank or buy a new one?? That is the question. Stock 1.7. A driver , not a hot rod. Reliable , inexpensive, not fast.

I guess first question is are you sure you even need a new crank. Has it been measured? Is it heavily scored, is it undersized and out of tolerance?

In my opinion, It's likely you can find a 1.7L standard size crank in good shape for less than the cost of grinding 0.010" or 0.020" (max) for what you have. Where I'm located, it ranges from about $80 - $130 to grind and polish a crank 0.010" under size. Just a polish is about $30.

I don't think 1.7L are in as high of demand as 2.0L and even 2.0L used, standard size cranks are still pretty reasonable and pop up on this site from time to time.

Nothing wrong with a ground crank as long as it is done properly and doesn't get rid of the journal radius to the crank cheek.

Competition Engineering has a very good machinist and builds dozens of VW & Porsche engines a year and have been for decades. PM me if you want more info- I work there part time

To answer the first question , both myself(old shade tree mech) and my son (factory trained Porsche and now factory trained Ferrari tech ) hear that little old rod knock. Not bad yet, but its there.... And I know exactly why. If machining prices are that cheap here, I'll just get the crank ground. The rest of the motor is still running fine. It was my daily before The tranny took a dump and I started down the slippery slope of rustoration!!