I was talking to the service guy today while I was waiting on my parents to finish the paper work on our new Dmax (which I really like by the way, don't slam me though, I'd still take my cummins anyday) and he was telling me that while cruising, the Dmax turns a cylinder off to save gas and when needed, turns it back on. Yall ever heard about this? Sorry to be asking so many questions about a Dmax on a Dodge board but I really trus you guys to give me an honest answer and I know you guys really well. Thanks for the help yall have given me.

 

Bigblue - There was insider info on this throughout the automotive industry a good while back. I think they were calling it displacement on demand or something. It could cut more than one cylinder. We were concerned with odd vibrations due to this, but I think they got it straight.

I did not know that they were doing it on the diesel. Our information was on the gassers.

Hope this helped.

John

 

I know about the gassers. Cadillac has been doing it for a while as have other manufacturers. I was just curious since I didn't know they were doing it on diesel's now.

 

Hmmmm, welllll guess they are trying to progress across the entire line.

I'm not so sure that I am convinced of this technique yet...time will tell.

John

 

Ive joked about this before...
My brother had a 1974 Chevy Vega that only ran on 1/2 of its cylinders all the time!
And it produced more smoke than any diesel Ive seen!



Rich

 

It was my impression that Caddy had dropped this, but could be wrong. Think they used to call it something like 8/4. 8 cylinders for power and four cylinders for cruising. Seem to remember that they had to drop it to four cylinders to achive the best balance but can't remember for sure after all these years.

 

Yes its called the 8/4 used to be 8/6 but they had balance problems. But they are only doing that to work onthe MPG deal. See if it works. :

 

I thought it was called: V8-6-4?
Gradually dropping cylinders?

4x4

 

The 8-6-4 fiasco was years ago when the caddy's were land yachts. GM had so much grief that they told their techs to disconnect the solenoids to just make it a V8 again. Sorta like when they told their techs to put gas engines in their diesel oldsmobile cars in the early '80's. Run. Run very fast. At one time Cadillac accounted for 10% of vehicle sales for GM and something like 50% of the warranty claim (that was a few years ago but came directly from the plant super (my uncle) at the St Cathrines axle forge plant.)

 

If I remember right, Cadillac used some type of unloader on each of the cylinders to be dropped off line, more of a headache than anything, especially when they wouldn't come back in and your stuck with a 4 cyl engine trying to push a TANK. The caddy diesel wasn't nothing more than a converyed gasser, they had BIG problems with the heads moving and bending the head bolts to the point that you couldn't get the heads off, so they just started putting in complete new engines. I just hope they didn't use the same genius to design the DMax engine

 

I once owned a 1979 Olds Delta 88 with the diesel engine. Heard about all the problems with that engine but mine turned out to be one of the best cars I have ever had. Installed HD springs all around with the heaviest duty shocks I could find. Great ride after that and it would corner with many sports cars. The engine finally and with no warning broke the crankshaft at 230,000 kms. When it did the vibration was so intense it shook every vee belt off the pulleys. Dropped a 350 4 barrel gasser into it but that just ruined the car. The gas consumption also doubled so sold the car quickly.
I also owned a 4 cyl Datsun and both vehicles would go the same distance for the same amount of dollars for fuel. Loved it.

 

Well thats one can we find two people who liked their olds diesel????
My father had one and got so sick and tired of the overheating that he just drove it until it cooked and the dealership took it on trade. It was 3 months old. He traded it for a Citation (another wonderful POS from GM) He has driven Toyota, Honda and Nissan ever since.

 

[quote author=PumpDaddy link=board=8;threadid=20996;start=0#msg197409 date=1066262694]
If I remember right, Cadillac used some type of unloader on each of the cylinders to be dropped off line, more of a headache than anything, especially when they wouldn't come back in and your stuck with a 4 cyl engine trying to push a TANK. The caddy diesel wasn't nothing more than a converyed gasser, they had BIG problems with the heads moving and bending the head bolts to the point that you couldn't get the heads off, so they just started putting in complete new engines. I just hope they didn't use the same genius to design the DMax engine
[/quote]

That was Cadillac's 1981 V-8-6-4 engine. It's right up there in the engine infamy list somewhere in the general vicinity of GM's and Volkswagen AG's '80s-vintage diesels. (Sorry Stan but you musta had a fluke). It's being done again on European Mercedes S class vehicles as an option. If I remember correctly a recent Autotech Daily column stated that it's coming back again in a Chrysler vehicle I believe. This time though I suspect the technology used is gigaflops ahead of what was available when Cadillac attempted selective cylinder deactivation.

 

Thanks for the info spots.

4x4

 

My brother had an Olds diesel that ran fine. Many did have problems, but some were fine.