We've encountered this many times with jobber concaves out of Canada. I won't name the Mfg., but here's what we do when someone has this problem. If you'll recall your old concave, it had 7 crossbars and your cylinder adjustment at zero on a new concave would have been usually 1_8" from the last crossbar (7th) and 1_4" from the front crossbar or twice the distance in the front (touching on the 7th, 1_8" on th front).