Cad V-12 may repeat failures of Cads past

[vectorclub]

Anyone who knows Cadillac history knows the V-16 engines of the 30s and the V-8s of the early 80s. These engines both features a "fuel saving" system. In the case of the V-16 one bank of 8 cylinders would be shut off. In the vcase of the V-8s in the 1980s they had a system called the 8-6-4 system. Both systems would shut cylinders off with no issues. It was trunung them back on that was the issue. Many V-16s and V-8s got stuck running on half of the cylinders. The fix was to disable the system completely.

This is why I am amazed tosee GM tempting fate again with new V-12 having a "fuel saving" cylinder shut off system. We may see history repeat itself again at Cadillac. SOmeone should remind Bob Lutz of Cadillacs past failures.

[2001 AE]

Originally posted by vectorclub
Anyone who knows Cadillac history knows the V-16 engines of the 30s and the V-8s of the early 80s. These engines both features a "fuel saving" system. In the case of the V-16 one bank of 8 cylinders would be shut off. In the vcase of the V-8s in the 1980s they had a system called the 8-6-4 system. Both systems would shut cylinders off with no issues. It was trunung them back on that was the issue. Many V-16s and V-8s got stuck running on half of the cylinders. The fix was to disable the system completely.

This is why I am amazed tosee GM tempting fate again with new V-12 having a "fuel saving" cylinder shut off system. We may see history repeat itself again at Cadillac. SOmeone should remind Bob Lutz of Cadillacs past failures.

Cadillac has come a long way since the 80's and with new microprocessor technology Cadillac will again tackle what they basically invented in the 80's but this time with much success. (see motortrend jan. 2002 issue mercedes V12 article) This idea has come so far other manufacturers are now going to use it and they must all thank Cadillac, the only company with the balls to try it.

[Hudson]

If you don't learn from your past, you run the risk of repeating it.

I'm sure Bob Lutz knows of GM's history, probably better than many people (including nearly everyone on this forum). The technology has improved greatly since the V8-6-4 engine. I have no fear that the "Displacement on Demand" concept is entirely feasible today. Mercedes-Benz thinks so.

[2001 AE]

Originally posted by Hudson
If you don't learn from your past, you run the risk of repeating it.

I'm sure Bob Lutz knows of GM's history, probably better than many people (including nearly everyone on this forum). The technology has improved greatly since the V8-6-4 engine. I have no fear that the "Displacement on Demand" concept is entirely feasible today. Mercedes-Benz thinks so.

Well said!

[delamothe]

Cadillac has been using the 468 system for quite some time on the Northstar power plant. It isn't an active control the way it was intended on the early 80's models. It merely takes over the motor on a"limp home mode" in the event there is a loss of oil pressure or coolant.

The V-16's of 1930-1940 never had any kind of engine management system. At least not the ones I've worked on.

As mentioned on another reply, the new controls are definitely more stout. For one, we use surface mounted components on thick film circuit boards. This very process has increased the reliability of electronic assemblies by many orders of magnitude. If there is any weakness in the solder, the minute the unit is tested, a fault will occurr within the test period. Back in the 80's 99% of electronic assemblies were through hole on s-glass boards. The boards were too prone to extremes in temperature expansion/cotraction, which led to stresses in the through hole components that were soldered to them.

A great contribution to fuel savings has been the recent use of distributorless ignition systems. They add a great deal of accuracy to the firing and timing process which normally is not efficient in a traditional distributor ignition. The computer now stores pre-programmed timing and dwell curves for different driving situations (city/ highway/ performance), keeping a very flexible set of conditions on the fuel injection and timing.

[CopperHed210]

Anyone who knows Cadillac history knows the V-16 engines of the 30s and the V-8s of the early 80s. These engines both features a "fuel saving" system. In the case of the V-16 one bank of 8 cylinders would be shut off. In the vcase of the V-8s in the 1980s they had a system called the 8-6-4 system. Both systems would shut cylinders off with no issues. It was trunung them back on that was the issue. Many V-16s and V-8s got stuck running on half of the cylinders. The fix was to disable the system completely.

They will probably make it without any troubles this time since everything has improved don't ya think?

[Starwind]

Corvette ZR-1 comes to mind when I think of disabling some HP out of the engine. I think Caddy will be fine with the new stuff.

[delamothe]

That's true, in addition, the ZR-1's motor was the first to use a distributor with an optical encoder. The distributor ran from the camshaft, and it turned an enclosed stainless steel wheel with 360 holes stamped around it.
These would make and break a beam of infra red light as the disk spins at camshaft speed, sending a train of pulses to the computer.
Then beneath those holes were some stampings of different arc lengths. These were specifically tuned to the firing duration of each cylinder. Very clever, and it shows how intimate GM engineers are with the response and performance of the 350.

Distributorless ignition is by far superior though. It has been perfected to an artform by most auto makers to date.

DIS modules have their own "intelligence" in the event the engine computer has a problem. The module reverts to a fixed duty cycle on the dwell (just like the old days of points ignition), and still gets its timing reference from the crankshaft sensor (usually a Hall effect device).

[kaskillah]

Originally posted by vectorclub
Anyone who knows Cadillac history knows the V-16 engines of the 30s and the V-8s of the early 80s. These engines both features a "fuel saving" system. In the case of the V-16 one bank of 8 cylinders would be shut off. In the vcase of the V-8s in the 1980s they had a system called the 8-6-4 system. Both systems would shut cylinders off with no issues. It was trunung them back on that was the issue. Many V-16s and V-8s got stuck running on half of the cylinders. The fix was to disable the system completely.

This is why I am amazed tosee GM tempting fate again with new V-12 having a "fuel saving" cylinder shut off system. We may see history repeat itself again at Cadillac. SOmeone should remind Bob Lutz of Cadillacs past failures.

The closest thing the V-16 had to being able to shut off a bank of cylinders in the 30's was that they had dual distributors, one for each bank of cylinders. They were not designed to run on only one bank. This may have only happened if you had a loose wire.