When I install wire O-rings, I use a mini handheld belt sander to do the first 45° scarf cut. Then, I walk the ring wire around, partially depth-set in place, leaving about 5/8” of a tail. Next, I mark the mating end with a felt tip marker. This gives you a visual reference to snip, and then scarf grind in place, so it mates seamlessly and invisible. Finally, I finish driving the whole wire into depth with an appropriately sized aluminum plate, working my way around. Even though there is no visible “seam”, for asphalt race applications, I prefer to have the joint at a head bolt hole, on the inside. If it were to ever leak, I’d rather have it go inside the engine than possibly on the race surface.
North Branch, MN