SHORTLY AFTER LIFTOFF; A CESSNA 182 PILOT NOTED MODERATE VIBRATION THAT CONTINUED TO INCREASE. ALL THE INSTRUMENTS FOR THEIR CONTINENTAL 0-470 ENGINE APPEARED NORMAL. PILOT CALLS FOR IMMEDIATE RETURN TO FIELD.

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PREFLT ACFT NORMAL. FOUND 2 SQUAWKS (MINOR): FUEL PROBE AND GATS JAR MISSING (BORROWED FROM NEARBY C182) AND TAXI LIGHT AND LNDG LIGHT SWITCHES BOTH OPERATED L LIGHT ONLY. UPON INITIAL PREFLT PWR-UP; ALL RADIO SWITCHES HAD BEEN LEFT IN THE 'ON' POS. PROGRAMMED GPS WITH 11 WAYPOINTS -- TOOK APPROX 20 MINS. ENG START AND TAXI APPEARED NORMAL. RUN-UP PARAMETERS ALL APPEARED NORMAL (LESS THAN 100 RPM MAG DROP BOTH A & B) WITH EXCEPTION OF CARB HEAT -- PREVIOUSLY BRIEFED NOT TO PULL FULL CARB HEAT DUE TO EXCESSIVE RPM DROP -- PULLED CARB HEAT UNTIL DROP INITIATED THEN PUSHED IN -- PROP CHK NORMAL. TKOF RUN APPEARED NORMAL -- ALL INSTS CHKED. SHORTLY AFTER LIFTOFF; NOTED MODERATE VIBRATION -- EXPECTED TO FIND OUT-OF-BAL TIRE; THEREFORE; APPLIED BRAKES -- VIBRATION CONTINUED TO INCREASE. PLT CALLED FOR IMMEDIATE RETURN TO ARPT. ENG INSTS APPEARED NORMAL. OBSERVER (CFII) MONITORED THROUGHOUT REMAINDER OF FLT. BELIEVE MAX ALT ATTAINED APPROX 600 FT AGL. VIBRATION CONTINUED TO INCREASE THROUGH DOWNWIND; BASE; AND FINAL. TURNED EARLY BASE/FINAL TO ASSURE MAKING RWY -- VIBRATION CONTINUED TO INCREASE. THROTTLED TO IDLE; HOWEVER; DID NOT SHUT DOWN -- VIBRATION CONTINUED TO INCREASE. PUT FLAPS TO 30 DEGS; HOWEVER; RETURNED TO 20 DEGS AFTER VIBRATION BECAME MORE SEVERE. OBSERVER STILL RPTED NORMAL ENG INSTS ON FINAL; ALTHOUGH VIBRATION CONTINUED TO INCREASE. LANDED LONG AND HOT (APPROX 75 KIAS). APPLIED FULL BRAKES BUT STILL APPEARED WE WERE GOING OFF END OF RWY. OBSERVER INDICATED WE MAY HAVE TO 'GND LOOP;' BUT PLT ELECTED TO ATTEMPT TURNOFF AT LAST TXWY -- BOTH TIRES BLEW WHEN THAT TURN WAS INITIATED. WHEN ACFT STOPPED; SHUT DOWN ENG AND CALLED UNICOM FOR HELP; THEN PERFORMED EMER EGRESS THROUGH R DOOR -- NO SMOKE/FIRE WAS APPARENT. ARPT POLICE; ARPT MAINT PERSONNEL; AND ADDITIONAL PERSONNEL RESPONDED IMMEDIATELY. ACFT SUBSEQUENTLY REMOVED FROM RWY AND TIRES REPLACED -- NO INDICATION OF OTHER EXTERIOR DAMAGE (RIMS/BRAKES/PROP/AERO SURFACES; ETC). COWLING NOT REMOVED; HOWEVER; ENG OIL DIPSTICK/TUBE APPEARED TO BE SEPARATED FROM MOUNTING AND POSITIONED WELL BELOW ACCESS DOOR. RESULTS OF ENG ASSESSMENT PENDING. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED AFTER LIFTOFF; HE NOTICED THERE WAS LESS VIBRATION AT HIGHER RPM'S AND MUCH WORSE WHEN THROTTLING OR IDLING. THE CONTINENTAL 0-470U ENGINE CONTINUED TO SHOW NORMAL INDICATIONS EVEN ON APPROACH. WHEN HE ATTEMPTED TO LOWER FLAPS TO 30 DEGREES; THE VIBRATION BECAME SEVERE; SO HE WENT BACK TO FLAPS 20 DEGREES. REPORTER STATED THE CESSNA 182 LOVES TO FLY AT 20 DEGREES FLAPS; SO HE ENDED UP LANDING HOT (FAST). NO EVIDENCE OF EXTERNAL FLIGHT CONTROL DAMAGE OR WHEEL OR STRUT PROBLEMS. REPORTER STATED AFTER FURTHER INSPECTION OF THE CESSNA'S SIX CYLINDER 0-470U ENGINE; MECHANICS FOUND ONE OF THE CYLINDER HEADS HAD PARTIALLY SEPARATED FROM THE ENGINE. THE 0-470 ENGINE HAD BEEN OVERHAULED APPROX ONE YEAR EARLIER.