| My bet is a partially clogged injector or poorly machined crank journal. There's no way that an aggressive tune is going to have that drastic of an effect on a single cylinder. Purely from a fundamentals of materials class 101 - given that you have six sets of everything, made out of the same materials, subjected to the same set of conditions - the maximum difference that you'll see on a properly functioning (or even on an extremely agressively tuned (detonating) car) is going to be maybe 10%. You simply don't have a wide range of wear unless you've got drastically different conditions within the engine. Spee and halo are simply wrong. Excessive stress/overdone tuning will certainly have an effect on an engine. You'll see it throughout the entire engine though. You don't have localized effects like this. You have small variations. Not catastrophic failures with adjacent identical parts coming out fine. Just doesn't happen. Genic's case serves to illustrate the point even further. Brand new OEM shortblock, JWT chip. JWT chip = not aggressive = very safe = NOT THE PROBLEM. JWT chips at 12 psi are safe, well within the safety margins of the program. Individual parts fail and cause catastrophic failures. Whole systems fail and also cause catastrophic failures. There's clearly a difference. That's why you can tear down an engine and almost always point to what went wrong. A single bearing failing like this points to conditions that affected ONLY that part of the engine, and not adjacent cylinders. The tune of the entire system cannot have this effect, plain and simple. Something is/was wrong with number 4. My bet is poor machining/cleanup work on the crank journal. Just looking at the picture of the chamfer (and maybe its just the pictures), it seems like the chamfer is not done symmetrically. Maybe its just the angle, but that doesn't look right to me. I'd pull the injectors and flow test them, that will certainly limit the possibilities for the failure. Perhaps it is a bad injector - but i'd put my money on the machining. I've done enough machining to know how much of a lip that type of chamfering can raise... certainly enough to cause this type of failure.
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Joe
Sport 530bb/Inconel
AIM: hoyatiger81
"You probably never even got you hands dirty working on a car. Take care toolbox!" --djtz1
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