While traveling around the country, I stopped in Santa Fe.  Leaving in the morning I noticed a unusual sound/shake to the plane…  kind of freaked me out as the just engine purred until that point.   Sort of a low rumbly noise/shake/vibration that I couldn’t quite put a finger on other than the vibration increased/decreased with RPM.  Almost more of a feeling that an actually noise.   Those who fly a lot know when something just isn’t right with their bird.   On reflection I remembered it was cool in the morning (not that cold) and I didn’t warm the engine as per my normal procedure.  It was a short taxi to an intersection departure.

After returning, I replaced the engine mount (a small crack was found) and rubber mounts as I thought it might be the problem…   This seemed to be resolved when just doing a few test flights around town.   Plenty of power, no increase in oil usage, good compression.   On the trip to RR I noticed it again only worst.  After returning to base, I decided to ground the plane again to find out what is going on.  

I think/HOPE I have finally found the problem today.   #2 cylinder was ringed with deep scratches top to bottom and AL build up on the cylinder wall.  After taking the cylinder off I found deep scratches on the piston too.  I’ll have to replace the cylinder.

I have read all about the piston damage to the cylinder from going to full power when the engine is not fully heated but in all my flying years, this is a first for me.  The AL piston expands faster than the steel cylinder when rapidly heated from cold.   Apparently the cylinder was gouged by the piston skirt because I didn’t allow enough time for engine to heat up. .  

It wasn’t that cold out (maybe 55 f), not that it mattered to the engine.  Maybe it was the change from a low compression pistons to higher compression pistons (more power and heat) which tipped the scales?  Who knows.  What pisses me off is I KNOW about this issue.  I have a Reiff engine per-heat system (http://www.reiffpreheat.com)  installed on the plane which heats the oil and band heater on all my cylinders to eliminate this issue IF I am at home with 110v available.  I just wasn’t paying attention to the conditions at the time and I must of just had a brain fart.  

So, the take away for those flying in cold weather is to properly warm the engine.  Do the research, to decide on your personal limits for oil/cylinder temps prior to going to full power for taking off.