I stay away from engine parts. Some plastic is fine to use.I've found that Huztl's products are hit and miss, qualitywise. I will definitely NOT be buying a cylinder from them anymore, I changed out a friends piston/cylinder on His Stihl concrete saw and it lasted one day. Checked and it had no compression, the cylinder was worn out. Went and looked at the pictures I took before assembly, and now noticed the cylinder had no chrome plating!