I do. Here's why:
When I bought my 1980 C-172, it had a Mattituck built O-320-D2J with about 800 hours on it. Compressions were good, UOA was clean. After about 450 hours of flying regularly (it never sat for more than 2 weeks, and usually only a few days), one of the cylinders lost compression. We pulled it, and saw the cam for the first time. The lobes had visible corrosion and pitting, slightly rough to the touch. The UOA reports never had elevated metals, so it didn't give any warning. Due to my regular flying and maintenance, I surmise that the cams were already pitted when I bought this airplane. Of course, you can't check that without pulling a jug so in hindsight I'm not sure I'd change anything about the pre-buy inspection.
Long story short, I replaced the engine with a Penn Yan O-360-A4M. After the break-in period I started using CAMGUARD (this appears in UOA reports as elevated Ca and P). I figure the experience was a $45,000 lesson and I might as well learn something from it, or do something different. It might not help, but it won't hurt, the cost is inconsequential, and given my experience, it gives me peace of mind.
When I bought my 1980 C-172, it had a Mattituck built O-320-D2J with about 800 hours on it. Compressions were good, UOA was clean. After about 450 hours of flying regularly (it never sat for more than 2 weeks, and usually only a few days), one of the cylinders lost compression. We pulled it, and saw the cam for the first time. The lobes had visible corrosion and pitting, slightly rough to the touch. The UOA reports never had elevated metals, so it didn't give any warning. Due to my regular flying and maintenance, I surmise that the cams were already pitted when I bought this airplane. Of course, you can't check that without pulling a jug so in hindsight I'm not sure I'd change anything about the pre-buy inspection.
Long story short, I replaced the engine with a Penn Yan O-360-A4M. After the break-in period I started using CAMGUARD (this appears in UOA reports as elevated Ca and P). I figure the experience was a $45,000 lesson and I might as well learn something from it, or do something different. It might not help, but it won't hurt, the cost is inconsequential, and given my experience, it gives me peace of mind.
