Hi all,,I have an 83 280ZXna with 160,000mls on it.The car runs awesome,but smokes when ideling about 10min.On start up and when cold,no smoke,driving normal temp,no smoke..But if she sits running about 10min or more,if I hit the gas,,it looks like a smoke storm.Im thinking valve seals..What do you guys think?If so,,it it a hard job?Does the cam have to be removed?Thanks.