A C172 PLT EXPERIENCED VERTIGO DUE TO VACUUM FAILURE; AFTER ENTERING IMC WHILE TALKING TO PHL.

Narrative

I HAD JUST ENTERED IMC; THE ATTITUDE INDICATOR AND HDG INDICATOR BADLY PROCESSED. APCH ASKED IF EVERYTHING WAS OK; BECAUSE MY ACFT APPEARED TO BE DOING S-TURNS. THE ATTITUDE INDICATOR SHOWED ME IN A 30 DEG TURN. THE CALL FROM APCH WAS A WAKE-UP CALL. PRIOR TO THE CALL; I WAS FEELING AN ONCOMING VERTIGO AND A QUEASINESS IN MY STOMACH. ATC GOT MY ATTN; AND I STARTED A FULL INST SCAN. I PUT MUCH EMPHASIS ON THE TURN COORDINATOR AND ALTIMETER; AND AIRSPD INDICATOR. AFTER THAT; I SETTLED DOWN. I THINK PART OF MY PROB WAS THAT I HAVE GOTTEN TOO USED TO THE AVIONICS IN MY FLYING CLUB'S MOONEY M20J (KFC ISO AND GARMIN +30); AND CIRRUS SR20 (HSI GARMIN +30); AND SUBSEQUENTLY GOT BEHIND THE AIRPLANE WHEN FLYING A 'NO FRILLS' VERY BASIC AIRPLANE. I LATER LEARNED FROM ANOTHER PLT THAT SPINS HAD BEEN DONE IN THIS AIRPLANE; AND THAT OTHER PLTS DIDN'T TRUST THE INSTS DUE TO ATTITUDE INDICATOR AND HDG INDICATOR PRECESSION. I GOT BACK ON THE HORSE THE NEXT DAY; AND HAND-FLEW THE SR20 IN HAZE BAD ENOUGH TO BE IMC. I HAD NO TROUBLE USING THEM ON APCH.