Just thought I'd pass this mag rough in flight experience on - and my question is - is there a life or hours limit on a Slick Mag for the 114B IO 540 engine?
In my last few hours of flight I noticed an increase of vibration level in the engine. In pre-flight it passed the ground mag check. In flight at both lean & rich mix settings I had a L mag run rough - when Ig sitch was on L mag it ran smooth then cut out momentarily, ran smooth again & so on. Ig switch on R mag engine was smooth. I landed and did the 1800 RPM ground check & it was fine but at 2200 rpm the L repeated the in-flight behaviour.
Was helped by a good A&P cleaned out & regapped plugs and said a couple were bad. Mag timing was checked & showed 25 deg on both (Jacksonville, IL IJX).
My conjecture was it couldn't be plugs since it was RPM dependant but always helps to clean plugs. With A&P onboard I ran ground check & it was fine - i.e. engine was smoother & both mags were the same - ditto at high power. A&P recommended keep fuel pump on till end of climb.
I took off and after 30 minutes in cruise noticed a higher level of vibration - mag checks showed same pattern again.
Was not too far away so landed in VPZ, (Valparaiso, IN) where Neil's mechanic is. By the way now upon doing a Mag flight check lost L mag completely (even a mometary engine silence sounds scary in flight you can be sure Ig switch was on L Mag for only a fraction of a second) i.e. no firing when Ig switch on L mag. Showed it to Professional Aviation in Valparaiso, IN - on ground check no L mag. He pulled mag and it showed internal damage not loss of capacitor or some other electrical problem.
I had the 500 hour check done by old Commander at the 2004 annual and was going to do it again on this year's annual since the Mag has a little over 1000 hours on it now.
Exchanged the mag for a re-built one from a place near Gary, IN and the plane is flying fine.
So my questions:
1 Is there a life limit on the Slick Mags for the IO 340?
2 What does the 500 hour check on the Slick mag check for or do?
Ruzic & Sid 114PW
114B @ PHF VA
1992 SN 14542