| I came across Monida Pass late in the day. Traffic was sparse, the roads were clear and I had been cruising at about 95 mph for 30 minutes looking forward to the end of a week long business trip. This stretch of interstate is about 40 miles of beautiful 4-lane scenery designed for "reasonable and prudent" touring... Speed loves company so it wasn't long before I had collected a newer Maxima and a new Dodge Charger in my draft. We were enjoying the skinny pedal playing leapfrog to pass the time. The Z was running strong and after cruising at about 110 for several miles it was easy to make the pretenders disappear in the rearview... Sanity returned at about 155 mph, so grinning ear to ear I backed off the gas and settled back down to cruise control at 80 mph. After a few minutes the Maxima passed nose to tail with the charger - I let them go with a fare thee well. During the course of this playtime I noted that the temperature and oil pressure we steady and normal. The boost controller was at 14 psi on 91 pump gas and the engine felt fine. (no audible detonation) However in some of the longer high speed pulls I did feel a little miss - and I was wondering if it was an engine issue or perhaps a clutch slip. Having the road to myself now I made a couple 5th gear WOT pulls to about 120 mph. On the second run I felt a cylinder fail and for a brief moment thought I smelled oil... It was dark by now so I couldn't "see" if I was actually burning oil. I backed down to about 55 and could feel a miss - oh buzz-kill! Temperature and oil pressure were still ok so I made the decision to see if I could coast the 10 miles down the pass into the next oasis. Bad choice - about two miles later I heard the piston fragment and rolled to the shoulder. So I'll save you the flame's - should have pulled over when I lost the cylinder and driving like an imbecile is irresponsible. (Boys will be boys, and it could be said that the only imbecile I was putting at risk was me.) Nuf-said. But here's the real issue - this is the 3rd time I've blown this engine. Each time under similar circumstances of top gear WOT runs. I'd kind of like to figure out what is going on befrore I rebuild again. I haven't done the autopsy on this engine, but the previous blowup melted piston #6 and that failure was caused by audible detonation. (I was in the car with a mechanic at the time trying to diagnose the problem. this was pre-boost controller) The first failure was a blown headgasket that may have been compromised when I bought the vehicle. By the light of day it was apparent that the oil smell was from oil blown out of the dipstick. I'm betting I find what is left of piston #6 has melted. So what's the trick to building an engine that won't melt down? With my mods the stock internals should be fine according to prevailing wisdom. The injectors were flow tested before the last rebuild. Compression numbers were good, all parts were OEM Nissan in the bottom end. JWT ecu. No boost leaks. Engine was in near perfect tune. Obsessive upkeep. I'm thinking maybe 5900 ft elevation could have contributed - but this time of year cold air is more dense. At 3500 ft (valley) I had carefully adjusted boost controller to safe level of 14 lb. I'd appreciate input on suspected failure mode and what to look for in my autopsy, and of course how to prepare an engine that will allow me to run redline and enjoy the skinny pedal. Thanks guys.
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