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Our elation after taking supply of a 2022 Cadillac CT5-V Blackwing for a 40,000-mile long-term take a look at rapidly turned to despair after its 668-hp supercharged V-8 suffered a catastrophic engine failure throughout our preliminary take a look at session. After respecting the 1500-mile break-in interval—maintaining the revs beneath 4000 rpm and never sitting at a continuing velocity for prolonged intervals—we hit the take a look at observe with simply over 1800 miles on the odometer to log its preliminary efficiency figures.
We took our time taking part in with the Blackwing’s exceptionally adjustable launch-control function that enables the motive force to pick out separate launch-rpm and slip-target settings, after which tried just a few unassisted dances on the pedals with our ham hocks to see if we may beat it (we may). After about 15 launches, we had been nearly able to name it when catastrophe struck. Whereas coasting to the far finish of the straightaway after a run, a bunch of warning messages popped up on the gauge cluster, all tied to a extreme misfire.
What occurred? That’s a very good query, one which wasn’t answered conclusively even following a whole teardown at GM’s powertrain headquarters in Pontiac, Michigan, the place the engine went after it was eliminated by our native Cadillac supplier. The injury was restricted to the even-numbered cylinder financial institution, with cylinder six taking the brunt of the carnage; its cylinder partitions had been scored, and aluminum plucked away from the sting of the piston and sprayed on prime of it in addition to on the exhaust valve. The extreme temperature and stress additionally blew off the bottom strap on the finish of the spark plug, and even the cast-iron cylinder liner confirmed some pitting.
Dangerous gas may have triggered this sort of pre-ignition or knocking, however then each banks would have been affected. So small-block assistant chief engineer Mike Kociba thinks it was doubtless one in all two issues that occurred: Both the gas provide on that facet of the rail was in some way depleted—a contaminant limiting the stream someplace—or an analogous blockage within the cooling system that allowed issues to get too scorching. However, throughout the teardown, they didn’t discover such a blockage in both system.
Kociba assured us it had nothing to do with the severity of our use, and that the engine can fortunately do standing-start launches all day. Moreover, he stated that of the roughly 20,000 supercharged LT4 variants of the Gen V small-block V-8 the corporate has offered so far—within the C7 Corvette Z06, Cadillac CTS-V, Camaro ZL1, and now the CT5-V Blackwing and Escalade V—ours is the primary and solely such failure.
Nevertheless, this isn’t the primary time a Gen V small block let go in our palms. The naturally aspirated LT1 V-8 in our long-term 2014 Corvette wanted to get replaced after a connecting-rod bearing failed, doubtless as a consequence of a steel burr that originated from the block or oil-filter threads.
With our CT5, it took about six weeks for our native supplier to take away the engine, obtain a brand new one from GM, and set up it. After which, in fact, we needed to take it simple as soon as once more throughout a second break-in interval.
Then we once more hit the take a look at observe for a lot arduous operating, and this time it took it in stride, clocking a dash to 60 mph in 3.7 seconds and 11.7 seconds by the quarter-mile at 124 mph, and shrugging off repeated runs. Simply as we’d count on from one of many fiercest-ever sports activities sedans.