Originally Posted By: 440Magnum
I love testing like that! And the temperature cycling is truly impressive. I wonder about the detonation testing, though. Pounding it like that over a period of 10 hours might still not be like driving it around detonating a little bit over a period of years. Seems like the pistons might embrittle and work-harden so they would fail instead of the connecting rods as in the short-term testing.
Its been done for decades, too. The engineers who built the 2nd-Generation Hemi on a tight schedule to make it to the 1964 Daytona 500 have written similar stories. Bill Weertman, Tom Hoover, and some other "Ramchargers" alumni. They had to buy all new dynos to run sustained tests on those engines, since they were the most powerful they had tested at that time and the dynos had to absorb full power for something like 12 hours straight. Their dyno building could test several engines at a time, and the exhausts were routed up and out the roof of the building. One engineer said he would never forget the sound, walking in to work in the dark before sunrise in a Detroit winter, of multiple, un-muffled 426 Hemis running at full power during the extended tests. And they had cycles of load/no load, hot shutdown/heat-soak/restart and so on. Nothing like the subfreezing coolant through a hot engine that I recall, though. That's a really good example of how far gasket technology, cylinder head clamping force design, and things like that have come.
I recall seeing somewhere testing for Chrysler's "dash 3" truck, marine, and industrial engines (318-3, 440-3, 413 Industrial, Chrysler Marine 354/392 Hemis) was something like 24-48 hours at WOT, alternating between HP and torque peaks. I also recall that the 440 6-pack was put to the same tests, which is one reason they got the HD bottom end parts!
