I drive a 1990 toyota camry 3sfe engine 95,000 miles four cylinder. When I start my car after it has sat for a while I get a puff of blue smoke then it stops smoking shortly thereafter, the valve seals are gone. My question is does anyone know a procedure for replacing the valve seals on an engine with Dual overhead cams and can it be done without removing the engine. Do you have to pull both intake and exhaust camshafts on this engine to get to the valve seals or can it be done with both camshafts in place??

Thanks for any help!!!