Here it is again! There was a discussion not long ago about this part, and I was advised the twist in back of the loop is not two turns. So, when I was at the archives recently, I pulled the print. Well, it turns out it is one and one half turns on one side, and two turns on the other! So we were both right! It all depends on which side you look at it on. The outside diameter of the loop is 1 1/16". While I'm at it, it disturbs me greatly when I see someone with a new brass radiator that didn't have the mentality to check where to drill the hole for the priming rod! I guess some folks just don't care.
Yes, some don't.