Have MB updated the 320CDi engine recently..perhaps since the 7g auto's were introduced. Just wondered if it is any quieter , smoother, etc.

 

For the US, it's the I6 and 5 sp.

 

Not sure about the US but in europe it's now an all new V6 powerplant that replaces the old I6 lump. I've test driven it with the new 7G box and it seemed about the same as my old I6 in terms of power but it was much more refined and just really doesn't sound like a diesel.

 

While it's more efficient and quieter, the I-6 is still both, and I'm sure with 18:1 compression, I'm wondering how an aluminum block V6 will hold up against an iron block I6.. the 100,000 miles test is cool, but it's not the same as driving a car for 20 years and to 300,000 miles +..

 

I was told by Mercedes tech person that the new engine wilol be here by early next year.

I will NOT trust the new engine until at least 5 years have passed. There is the potential of a HUGE problem with the cast iron/aluminum combination. Yes, I know they tested it to death but that is the same thing they said about SBC.

 

Aluminium block and cylinder heads. Magnesium transmission housing.

Which cast iron/aluminum combination ?

(C320CDI arriving in two weeks)

 

I think he typoed that... the Cast iron/aluminum is the current I6.. with aluminum heads..

the new engine is all aluminum, and the problem is whether the compression of a diesel will cause problems for the cylinder walls, especially when the engine is not all the way warm..
time will tell.

BTW... just watched Motorweek and they did the E320 CDI... awesome road test, and the just loved it.. it took the slalom well, and the braking was an amazing 126 feet. They also got a 0-60 in 6.8 which makes sense, since with RennTech I'm getting about 6.5 to 6.6 ..

I wish they didn't need to go to this Aluminum engine.. but then I guess since they wanted a V8, and alloy V8 is a lot lighter than a steel one.. and that is probably the major reason, and the fact that they need space to install it into shorter hood cars like ML's..

I went on an MB board that is mainly populated with mechanics and most of them that I asked said the I-6 would be their choice, so I feel good about having that vs the new V6.

 

What is "it"? The I6 or the V6?

 

Nope, it is not a typo.

Mercedes has developed a "new" process were they cast the aluminum around cast iron cylinders. Essentially, they are trying to get the longevity of cast iron and the lightness of aluminum. The problem is that these two metals have a vastly different expansion and contraction rate. This can have a detrimental effect on the longevity of the engine. Imagine the stresses that will be created when you start the engine from minus 30. It's not that either one of these metals is breaking new ground, it's the direct connection between the two of them. The joints are going to be constantly stressed under expansion and contraction, particularly in a diesel.

To alleviate (hide?) the problem, Mercedes is softening the start up power until the engine hits a certain temperature. Their 100,000 straight "endurance" run amounts to a hill of gas inducing beans. Actually, it amounts to false and misleading advertising. The thousands of starts and resultant heating and cooling down (contraction and expansion) of this engine is what is CRITICAL, not starting it once and then running it for a couple of days.

This engine was primarily designed to be small enough and light enough fit into as many Benzes as possible and to allow them to machine it at the same line as their V-8. It was designed as a sales tool for their CONVINIENCE. No thanks.

Cast iron blocks and aluminum head are ATTACHED by bolts and there is a gasket between them. This allows some differential expansion and contraction with out detrimental effect. In the case of the "new" engine, they are connected (cast) to each other and Mercedes hopes and prays that the joints will survive tens of thousands of start-ups. If not, well, what the hell, those dumb customers can buy new cars. Right? :v

If this is another boondoggle like SBC, it will further ruin Mercedes reputation and deservedly so. I suggest that if anyone is interested in the CDI, they buy it BEFORE the engine change. Let OTHERS be the lab rats. As an engineer, I love to push technological limits but as a customer, I do NOT want them to experiment with MY hard earned money.




http://www.germancarfans.com/news.cf...ercedes/1.html

 

why the I6 of course!

 

OK Thanks, that's a reasoned discussion. Will let you know how it goes. Good article too.

 

The name of the company that make the new V6 is Hydro. Here's an article on the new V6 block:Aluminum V6

At the bottom of the article, you can download a hi-res picture of the blocks...