Narrative:

I thought the weather was perfect for flying a few practice approaches in IMC. The engine had just been overhauled less than 200 hours prior. By the time I departed the instrument conditions had dissipated locally; however it was still IMC about five miles west. Upon departure; I requested and flew several practice approaches in IMC; landed for fuel and took off again for more practice approaches.once airborne and while in the clouds I was discussing approaches with center; when the aircraft began to shake violently and it sounded like the engine was shutting down. I glanced at my tachometer and even with full throttle and full mixture; I was only showing 1;700 RPM. I was unable to maintain level flight and began descending. Immediately I declared an emergency with approach but started to experience radio trouble when my transmit button wouldn't click. Center began vectoring me; however I was having difficulty maintaining a heading while trying to resolve the shaking problem. I considered turning on the autopilot; but thought that may exacerbate the problem if the autopilot tried to maintain level flight with not enough power. I thought about aiming for two nearby highways since both were on my mfd; but decided it was too risky. A few minutes later approach suggested that I return to my departure airport since it was VFR (albeit only a 1;000 ft ceiling). I took their suggestion and turned around using GPS for navigation.at this point I was about 2;000 MSL. The oil pressure annunciator and alarm came on. I glanced at the oil pressure and it was reading zero. I relayed this information to approach in case I did not survive the crash. I used approach for every possible resource and eventually declared an emergency. At this point I was at about 1;800 ft. As I continued to descend; it seemed to them that I wasn't going to make it back to the airport. They suggested that I divert to a closer but shorter airport. After some strong suggestions from approach; I decided to divert as they suggested. At this point I was at about 1;500 ft and I asked approach; 'how low can I go here' and they told me; 'minimum vectoring altitude is 2;000 ft'. A few seconds later; they told me; 'radar contact lost'. I told them I could still hear them at my altitude. Around 1;200 ft MSL (600 ft AGL); I broke out of the clouds and saw the approach end of the short runway directly below me. I knew I couldn't make it down from my position so I broke off into a left downwind in the opposite direction. The engine sounded like it was going to quit any second; so I was fearful to continue my downwind too far in case I didn't have enough power on final to make it all the way back. When I turned base; I initiated a steep turn but kept my airspeed up to avoid a stall/spin. As soon as I turned final; I put on full flaps and aimed for the numbers. I was speeding up too fast; but I knew if I leveled the aircraft; I would never have touched down. I made contact with the runway in a pseudo-flare well above stall speed. I was about 1;000 ft down the 2;005 ft runway before touching down; which was followed by several bumps while I tried to stay down. As I neared the end of the runway; I knew I wasn't going to stop in time; and steered clear of several small trees until coming to a complete stop in the brush. I immediately pulled the mixture and got out.first I called approach and let them know that I got down alive. They took this to mean that I got down without any problem and they canceled the fire department (but didn't tell me). I could see steam coming from the engine and it smelled of burning oil. Oil was splattered all over the left side of the engine cowling. I checked the dipstick. It read zero. I contacted the mechanic and told him what happened. When the mechanic arrived he removed the cowling to find that at least two rods were bent. He believes that at least two cylinders seized and bent the rods; which then dumped oil out as the engine keptrunning; resulting in the late oil pressure annunciator. No one was injured in the event and at this time; there doesn't appear to be any significant damage to the aircraft; other than a seized engine.

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Original NASA ASRS Text

Title: When the recently overhauled engine in the C-172 lost significant power due to pushrod failures while in IMC the pilot received assistance from ATC to divert to a nearby airport where he broke out high; landed long and ran off the end of the runway.

Narrative: I thought the weather was perfect for flying a few practice approaches in IMC. The engine had just been overhauled less than 200 hours prior. By the time I departed the instrument conditions had dissipated locally; however it was still IMC about five miles west. Upon departure; I requested and flew several practice approaches in IMC; landed for fuel and took off again for more practice approaches.Once airborne and while in the clouds I was discussing approaches with Center; when the aircraft began to shake violently and it sounded like the engine was shutting down. I glanced at my tachometer and even with full throttle and full mixture; I was only showing 1;700 RPM. I was unable to maintain level flight and began descending. Immediately I declared an emergency with Approach but started to experience radio trouble when my transmit button wouldn't click. Center began vectoring me; however I was having difficulty maintaining a heading while trying to resolve the shaking problem. I considered turning on the autopilot; but thought that may exacerbate the problem if the autopilot tried to maintain level flight with not enough power. I thought about aiming for two nearby highways since both were on my MFD; but decided it was too risky. A few minutes later Approach suggested that I return to my departure airport since it was VFR (albeit only a 1;000 FT ceiling). I took their suggestion and turned around using GPS for navigation.At this point I was about 2;000 MSL. The oil pressure annunciator and alarm came on. I glanced at the oil pressure and it was reading zero. I relayed this information to Approach in case I did not survive the crash. I used Approach for every possible resource and eventually declared an emergency. At this point I was at about 1;800 FT. As I continued to descend; it seemed to them that I wasn't going to make it back to the airport. They suggested that I divert to a closer but shorter airport. After some strong suggestions from Approach; I decided to divert as they suggested. At this point I was at about 1;500 FT and I asked Approach; 'How low can I go here' and they told me; 'Minimum Vectoring Altitude is 2;000 FT'. A few seconds later; they told me; 'RADAR Contact Lost'. I told them I could still hear them at my altitude. Around 1;200 FT MSL (600 FT AGL); I broke out of the clouds and saw the approach end of the short runway directly below me. I knew I couldn't make it down from my position so I broke off into a left downwind in the opposite direction. The engine sounded like it was going to quit any second; so I was fearful to continue my downwind too far in case I didn't have enough power on final to make it all the way back. When I turned base; I initiated a steep turn but kept my airspeed up to avoid a stall/spin. As soon as I turned final; I put on full flaps and aimed for the numbers. I was speeding up too fast; but I knew if I leveled the aircraft; I would never have touched down. I made contact with the runway in a pseudo-flare well above stall speed. I was about 1;000 FT down the 2;005 FT runway before touching down; which was followed by several bumps while I tried to stay down. As I neared the end of the runway; I knew I wasn't going to stop in time; and steered clear of several small trees until coming to a complete stop in the brush. I immediately pulled the mixture and got out.First I called Approach and let them know that I got down alive. They took this to mean that I got down without any problem and they canceled the fire department (but didn't tell me). I could see steam coming from the engine and it smelled of burning oil. Oil was splattered all over the left side of the engine cowling. I checked the dipstick. It read zero. I contacted the mechanic and told him what happened. When the mechanic arrived he removed the cowling to find that at least two rods were bent. He believes that at least two cylinders seized and bent the rods; which then dumped oil out as the engine keptrunning; resulting in the late oil pressure annunciator. No one was injured in the event and at this time; there doesn't appear to be any significant damage to the aircraft; other than a seized engine.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.