From Revach:
The Arizal would not let his Peyos grow longer than the required length andwould cut them when they exceeded that length. The Shineveh Rebbe told the Darkei Tshuva (181:15) that this is based on what Rav Chaim Vitalwrote regarding long hair.
In a letter to Rav Menashe Klein (Mishneh Halachos 5:124) a questioner wanted to know why, based on this, is it permitted to grow peyos beyond the required length? Rav Menashe Klein writes that although he does not want to c”v argue with the Shineveh Rebbe, however the Shulchan Aruch explicitly writes that one should not touch his peyos. Furthermore we don’t find anywhere any issur to let them grow. Also it is known that Rebbi Akiva Eiger wouldnot even brush his peyos with a comb. Moreover he says, he has seen Shineveh grandchildren with long peyos.
In 4:116 Rav Menashe Klein plays on the words of the mishna referring to the mitzva to leave Pei’a in the field. “Eilu Devarim She’ein Lahem Shiur Hapei’a”, these are the things that have no limit, the peyos.
Interestingly in 6:149 he brings from the Maharshal that one should not cut his hair except opposite the back of his neck for health reasons. This goes against the Machatzis HaShekel who says that long hair is a Chatzitza for tefilin. He also brings from the Ibn Ezra who says that in principle one should never cut his hair or beard as it is the Tiferes of a person, although the actual issur of the Torah in only applies to the peyos.