[Elarson]

A recap of Bowling Green and what we've learned.

Run #1...6.241 record. Lit on all 8 cylinders but detonation in cylinder #2. Burned the ground electrode off the spark plug but it was still firing. So the MSD 44 amp mag can jump at least an effective .135" gap. Bent the wrist pin (1.095 pin diameter). Looking back at the data, I can see that we were losing more oil pressure than normal, late in the run. It's normal to drop off some due to warming and diluting the oil with fuel.

Run #2 Oil pressure was lower than normal after firing the engine. In hindsight, we should have aborted the second attempt. In the future we'll know that we HAVE to have 150 psi at idle or else we don't run.

Car launched as hard as the first run, lit on all 8.
At 0.53 seconds, cyl #6 drops.
At 1.05 seconds, cyl #5 drops.
Somewhere around 1.2 seconds, rod bearings #5 and 6 spin and rip the caps off the connecting rods. Shrapnel begins to fly around crankcase.
At 1.29 seconds, a chunk of shrapnel wedges a cam lobe against the block, shears cam key, engine quits running (but is still windmilling). Some intake valves now hung open.
Next revolution, the mag fires and the spark in the cylinders with open valves burns up into the intake and bangs the blower.
At 1.39 seconds, blower explosion pressure peaks at 69 psi.
Blower case is broken into 4 pieces
Note that the whole failure sequence took less than 1 second.

Now the good news.

Pistons in the other 6 cylinders have no skirt cracks, validating that looser piston-to-wall clearance was the right move.
Iron IA-2 block looks like it needs cleanup in the 2 scuffed cylinders and it's probably still useable. That will be a winter project.
If we wouldn't have been detonating cyl #2 in the first run, it would have been even quicker than 6.241.
SFI 14.3 blower restraint contained the blower explosion; preventing launching the case sides thru the body and into the grandstands.

Eric