Hi there,<br /><br />I have a '78 55 HP Johnson.<br />I had it rebored, because I had too much piston ring end gap and eventually too much piston to cylinder clearance.<br />I've ordered 2 Wiseco 0.030" oversize pistons (3.217" bore size) and gave them to my machine shop to rebore the powerhead.<br /><br />Now I've measured the piston ring end gap. Three rings measure approx. 0.024" and one ring measures approx. 0.022". I measured evenly in both cylinders on top & bottom so I assume the cylinders are round & evenly.<br /><br />My oem Johnson manual calls for a ring end gap of min. 0.007" and max. 0.017" and Wiseco says 0.004" x bore size, so that will be 0.004" x 3.217" = 0.012868" minimum ring end gap. Wiseco didn't describe the max. ring end gap, only the minimum.<br /><br />So my readings don't fall between the specified tolerances although Wiseco doesn't provide a maximum ring end gap.<br />I don't know anymore what is wrong or right. Did my machine shop rebore too much (they had both the pistons), or do these Wiseco's cause the problem, or don't I even have a problem at all?<br /><br />Some help is greatly, very, very appreciated!