GYROSCOPES FAILED IN IMC.

Narrative

I WAS APPROX 10 MI SE OF EUG ARPT; VFR BTWN LAYERS. MY DEST WAS HIO ARPT AND RPTING 3000 FT OVCST AND 20 MI VISIBILITY. I REQUESTED AN IFR CLRNC TO HIO AND EUG APCH SAID THEY WOULD WORK ON IT AND TO STAND BY AND REMAIN VFR. THE VISIBILITY DETERIORATED AND I WAS IMC. I ASKED EUG APCH HOW MY CLRNC WAS COMING AND THAT I COULD NO LONGER MAINTAIN VFR. APCH GAVE ME A SQUAWK AND MADE RADAR CONTACT AND CLRED ME TO 6000 FT MSL. DURING THAT XMISSION I MADE CORRECTIONS TO MAINTAIN CTL OF THE AIRPLANE BASED ON INFO I WAS SEEING ON MY ATTITUDE INDICATOR. I SOON DISCOVERED THAT I WAS RECEIVING ERRONEOUS INFO FROM MY AIRSPD INDICATOR AND I WAS IN AN UNUSUAL ATTITUDE AND HAD NO SUCTION; THEREFORE RENDERING MY AIRSPD INDICATOR AND DIRECTIONAL GYROSCOPE INOP. THE VACUUM PUMP WAS WORKING FROM PRETKOF UNTIL THAT POINT. I QUICKLY INFORMED APCH I HAD NO GYROSCOPES AND REQUESTED NO GYROSCOPE AND REQUESTED TURNS TO VECTORS TO HIO. DURING THE NEXT 15-20 MINS I HAD DIFFICULTY KEEPING THE ACFT ON A SPECIFIC HDG AND HOLDING ALT. I ATTRIBUTE THIS TO DISTRS FROM TUNING IN THE LORAN TO HIO AND GIVING ME TRACKING INFO WHILE MAINTAINING CTL OF THE AIRPLANE UNDER PARTIAL PANEL CIRCUMSTANCES. THE REST OF THE REMAINING 40 MINS TO HIO IN IMC WAS WITHOUT A PROB DUE TO NO FURTHER COCKPIT DISTRS AND ADDITIONAL NAV INFO FROM THE PROPERLY SET LORAN. I MAY ADD THAT THE PROFESSIONALISM OF THE EUG CTLR WAS EXCELLENT AND THAT HE DID AN OUTSTANDING JOB ON THE NO GYROSCOPE TURNS INSTRUCTIONS. THIS WAS A GOOD EXAMPLE OF HOW A ROUTINE FLT CAN BECOME VERY CHALLENGING; VERY QUICKLY; AND HOW ALL THE PRACTICE AND SKILLS A PLT POSSESSES IS PUT TO THE TEST. THE VACUUM PUMP HAS BEEN REPLACED; AND ALL SYS AND INSTS HAVE BEEN RECERTIFIED FOR IFR.