end of problem..have replaced cam follower assembly...cam was clean..valve good..actually follower looked good but replaced any way....Lift is correct...all adjusted up valve cover on...Dodged a bullet this time..Conclusion the retainer clip broke jammed the spring and broke it (follower spring).Must have caught it shortly after it happened... Thanks to all for the education and great input Busses are good!! no parts in pan help good feeling!