engine knock
 

i (and a friend) just finished the process of getting an eng started that had sat, under cover, for about 35 yrs. some stuck valves, and great difficulty getting head removed. evidence of much low quality work abounded.(a wingnut holding the batt box in for instance) but we got it lit off, and there is a prominent noise. doesn't have the low thud that i associate with a main. shorting plugs one at a time does not make the noise go away, but changes it some. however, retarding spark makes the noise all but disappear. it really doesn't make much difference, but does anyone have an idea what i can tell the owner what it might be? thanx, roger

Re: engine knock
 

Center main. When a motor sits for extended periods the oil in the tubes to the mains can become hardened and take out the bearings in short order.