snowdog61
Contributor
Just finished rebuilding the GF's MK20 and after putting pressure to it, it locked up at 147 - figured I'd need to remove a shim at some point so started into seating it and began cycling the 2nd stage which dropped the IP to 115ish and returned to around 135 where it paused but then climbed back to 147. I attributed this to the seat and knife edge getting acquainted. After removing the thinner of the 2 nylon shims and cycling the 2nd stage probably 40 times the IP would pause at 125ish and creep over 5 seconds or so then hold at 137 consistently. Since it was consistent, I'm thinking it is OK but I'm not getting the reason for that creep. This is my 1st piston type reg so not sure what to expect - maybe the parts were just breaking in? My other rebuilds were all diaphragms and they have all locked up solid with little to no creep. Piston knife edge looked smoothed and polished under magnification.