I was reading about this one-year-only engine from Cadillac that was available in 1981. Just found it interesting.
From Wikipedia:
For 1981 Cadillac introduced what became the most notorious engine in the company's history, the V8-6-4 (L62). The 368 had not provided a significant improvement in the company's CAFE numbers, so Cadillac and Eaton Corporation devised a cylinder deactivation system that would shut off fuel to two or four cylinders in light-load conditions like highway cruising, then reactivate them when the throttle was opened. A dashboard "MPG Sentinel" gauge could show the number of cylinders in operation, or instantaneous fuel consumption (in miles per gallon). The L62 produced 140 hp (104 kW) @ 3800 rpm and 265 ft·lbf (359 N·m) @ 1400 rpm. Cadillac hailed the L62 as a technological masterpiece, and made it standard equipment across the whole Cadillac line.
While cylinder deactivation would make a comeback some 20 years later (with modernized technology), Cadillac's V8-6-4 proved to have insurmountable teething problems, both mechanically and electronically. The biggest issue was that the engine control computer was simply not fast enough or powerful enough to efficiently manage the number of cylinders in operation, so many of these engines had their variable-cylinder function disabled by dealers, leaving them with permanent eight-cylinder operation. The 368 was dropped for most Cadillac passenger cars after the 1981 model year, although the V8-6-4 remained the standard engine for Fleetwood Limousines and the carb 368 remained in the Commercial Chassis through 1984.
From Wikipedia:
For 1981 Cadillac introduced what became the most notorious engine in the company's history, the V8-6-4 (L62). The 368 had not provided a significant improvement in the company's CAFE numbers, so Cadillac and Eaton Corporation devised a cylinder deactivation system that would shut off fuel to two or four cylinders in light-load conditions like highway cruising, then reactivate them when the throttle was opened. A dashboard "MPG Sentinel" gauge could show the number of cylinders in operation, or instantaneous fuel consumption (in miles per gallon). The L62 produced 140 hp (104 kW) @ 3800 rpm and 265 ft·lbf (359 N·m) @ 1400 rpm. Cadillac hailed the L62 as a technological masterpiece, and made it standard equipment across the whole Cadillac line.
While cylinder deactivation would make a comeback some 20 years later (with modernized technology), Cadillac's V8-6-4 proved to have insurmountable teething problems, both mechanically and electronically. The biggest issue was that the engine control computer was simply not fast enough or powerful enough to efficiently manage the number of cylinders in operation, so many of these engines had their variable-cylinder function disabled by dealers, leaving them with permanent eight-cylinder operation. The 368 was dropped for most Cadillac passenger cars after the 1981 model year, although the V8-6-4 remained the standard engine for Fleetwood Limousines and the carb 368 remained in the Commercial Chassis through 1984.
