Performed 100HR inspection on engine Lycoming 0-320-E2D S/N L-34839-27A. Comp CHK #1-78 #2-78 #3-76 #4-78. Drained oil + filter P/N CH48111-1 and add to lots of AeroShell 100 plus. Cut + insp filter no metal found. Removed + cleaned spark plugs, gapped, tested, insp OK. F/R #3+4 oil return lines. All work done IAW Cessna 172 MM IPC + FAR's. I certify that this S/N was inspected IAW Cessna 172 100HR checklist and was found to be in airworthy condition and is approved to return to service at this time.