I don't know exactly what happened. The wrist pin is pretty much seized on the connecting rod, and the other end of the rod spins freely on the crank. That's where most of the damage came from, the remains of the other part of the rod. The close ups of the outside are the 2 holes it cut, you cand literally look right through it. On the head and piston pics, I guess I was a little too close. I was trying to show the marks from the piston hitting the valves. I don't actually think they are bent, but it was enough to scrape the carbon off both the valves and piston.
Yes less than every 3k. I rebuilt that motor last summer and I've been beating the crap out of it. I babied it for like 1500 miles, I remember exactly where I was when I first really opened it up, and I'm pretty sure it bounced off the limiter every day after that...
Well, not quite, but this happened during an autocross, where I was winning (still took 3rd, beat a Ferrari). I was pretty low on fuel, and I think it leaned out or something when I went around a corner and there wasn't fuel in the pickup. The run before I had felt it do that when I went through a quick lane change and then accelerated hard, it just lagged a lot. The next time I was in an off-camber rotary at near redline in first and it just started making weird noises. I finished the run (my second best of the day, and also the very last one for my class) and it sort of sputtered and sounded like it had dropped a valve. I tore it all down and checked everything I could think of. The head was fine and the rod bearings were fine too. I got it back together after some headaches, and two weeks after it started making the noise I let it warm up, sounded ok, there was a little tick like the valves were out of wack, nothing unusual. I took it around the parking lot and got to about 3000 RPM and it just blew up, there was a lot of noise, a lot of vibration, and the oil light came on...
then I drove the HF to Rhode Island and picked up another motor... which is giving me so much crap going in... must not drive it too hard......
Anyway other than driving it pretty aggressively, I don't know what I did wrong. I know everyone that knows me says I drive it too hard, I never over-revved it, and it was pretty old to begin with (230k). I don't have any problems with taking the motor to it's redline/limiter on a regular basis. I've seen more engines break from bump starting. Honda designed the A6 with a fuel cut at 7200 RPM, why not 7000 if that's unsafe?
Now someone tell me I'm wrong.
I tore it down finally today to keep the good parts and throw out the rest . The #1 piston/rod was the broken one. The rod bearing was flattened out and stuck to the crank. When I took it all apart, it was so smooth I didn't even notice, until I realized there was no oiling hole on that one. Needed a flathead and a couple of taps to separate the bearings. They were paper thin and scored badly. #2 and 3 were fine, but the ring lands partially broke on the #4 piston. They were kind of in there, but while I was taking the rings off metal sort of fell out into my hand.
So I have 2 good pistons/rods, the sensors, the crank, and the thermostat housing piece. I kept all the bolts and the easily removable things, but my first motor is now in the bottom of the scrap metal barrel.
I'll miss my A6...... until the mini-me starts up!
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