Big Richard and Styria,
I had a feeling that I might be raising the ire of 6.9rs when I referred to the 6.9 as lacking the durability of some other Mercedes. Now, first of all, I would gladly take over someone's 6.9; I'm not knocking them as being inferior. ANYTHING BUT! But let it be said, as I've been trying to find literature on the 450 SELs, I've come across a lot of articles such as
http://www.channel4.com/4car/100-greatest/classics/mercedes-s-class.html, which says, "With the 6.9 be very wary of any mechanical troubles as the M100 is specialised and expensive to work on. Gearboxes, prop shaft joints and final drives take a hammering on this torquey model." If you have the money to repair these beasts, they are awesome cars to have. But if you're not someone who is willing to pay big bucks, it is probabely not the car for you. At least, that's what the Sep 99 buyers' guide from Unique Cars says: "Unlike the 4.5-litre cars, the 6.9 used hydro-pneumatic suspension and dry-sump lubrication, multiplying repair costs if something fails and rendering them less practical for everyday use."
At the same time, I have a Road & Track Evaluation by Peter Bohr that says, "I've driven a number of early 4.5-liter SLs with 750,000 or more on their engines," said Rugg. "At a million miles they get a little edgy". That may be stretching things just a bit, according to Cunha and Marx. But both agree the iron-block V-8s are exceptionally long-lived. "Around 350,000 before a bottom-end overhaul isn't unrealistic," said Cunha. "The top end is often good for 180,000-240,000 miles." And from Marx, "I have some customers with at least 300,000 miles on their cars and the engines haven't even needed valve jobs." It seems to be common knowledge that true high performance cars are generally expensive propositions to maintain. To give an extreme analogy: Indy cars are built to scream for 500 miles; they would fare terribly on a cross-country jaunt. I'm glad that Big Richard's 6.9 has 193,000 miles (and here's to hoping you double that!); but the fact remains that there are million mile 4.5s out there.
I like Styria's post. It gets to the heart of my question: how does one define quality in a car? He is clearly pointing out that quality is in the eye of the beholder, because there are numerous categories, and one prioritizes based on his own value system. That was really why I introduced the 6.9 and the Jaguar (and now Indy cars): the Indy engine is a high quality engine built for a specific purpose; if you try to judge it by a different criteria than which it was designed for, you will get garbage.
The most important question is this: how do we w116 owners define quality? Why do we think of our cars as quality cars?
I've been thinking about a post I read over on mercedesbenzforum.com titled, "What in the !?!? is going on?" He was genuinely outraged at Mercedes quality over the last 10 years measured in terms of breakdowns and high part/component failure levels. Now, maybe I'm wrong, but I always thought that Mercedes cars went on and on forever. That was what made them quality cars. Now I'm wondering if they really are that much more durable than American and Japanese cars that cost much less.
At the same time that I say that, I can also tell you that I've never enjoyed looking at any car I've ever owned as much as I enjoy looking at my 116. And again, maybe the secret of million mile MBz cars (and this includes the 6.9's) is owners who have such passion for their cars that they are willing to do whatever they have to do to keep their beloved cars on the road.