| :fact that our engines have a significant load at both the front and rear of the crankshaft, which I think would make the central cylinders produce a significant amount of deflection in the crankshaft... *shrug* I think the crank is too short to see 4th order in the normal rev range. I would look to detonation as the culprit. Have you done the water jacket in the block mods? The poor water flow really contributes to uneven heating of the combustion chambers. Also I think you probably tune more to the edge in your ECU than others from reading many of your prior posts. For instance I have anecdotaly heard that you carry 22 degrees in the high load part of the spark map. In my experiance thats a lot for pump gas. The VG pings loudly and its and easy engine to hear detonation in but perhaps you are surfing the edge of detonation and are getting rough combustion. This still spikes up the combustion pressures. If you could provide better pictures I could tell better but it looks like transient load related damage. Mike
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