Ok, I see what you're getting at. Like I've mentioned on earlier topics, overall I was very impressed with John Deere engineering when I worked for a Deere dealership. There are exceptions of course (for instance, their 200-series skidsteer was garbage. The 300-series was a big improvement, but still not up to their standards IMO)- every company has spectacular failures now and then. But overall, I think their machinery's function and durability, their customer support, and parts availability are second to none. There aren't many companies out there that still STOCK parts for 50 year old machinery- but Deere does. My overall impression was the Deere equipment is one of the most expensive out there- but also some of the best quality, functionality, available options, and resale value available.
The Deere dealership I worked at sold and primarily serviced agricultural equipment. The Case dealership I worked for sold and serviced construction equipment- so this isn't an apples-to-apples comparison. But generally speaking, I found Case equipment to be much simpler than deere equipment, significantly cheaper, but also of lower quality. Their parts availability was mediocre AT BEST- [censored], we had trouble getting some parts for machines that were only 15 years old. And I wasn't terribly impressed with their fluids, filters, and such. Nowhere near the selection or quality that was available from John Deere or even Cummins. Overall, compared with Deere, I have the impression that Case equipment is relatively cheap and basic. It usually works well enough, but it isn't as durable, there are fewer options available, and resale value isn't that great.
I went through my opinions of the two tractor companies so as to put my opinion of Detroit Diesel in context. Detroit, in my opinion, is more similar to Case than to Deere. The Series 60 engine, for example, is relatively cheap... isn't available with as much power as comparable Cat and Cummins engines, ALWAYS leaks oil, and just doesn't SOUND good- even when running properly. That isn't to say that the series 60 is a BAD engine... just that it's a simple, basic engine that costs less than the competition and often gets better fuel economy. But it isn't as durable, doesn't have the resale value, or as good after-sale support as other brands, in my experience. I've overhauled lots of engines over the past 14 years or so. Mostly Cummins, Deere, and Detroit engines. Of all the makes and models I've worked on, Detroits parts have the WORST fit and finish of any that I've seen. The machining is often very rough, defective parts are common, remanufactured parts are usually all dinged-up as if the cores were simply thrown in a pile. The series 60 block has more cavitation problems than any other engine I've dealt with. BLOCK cavitation is actually pretty rare in other makes of diesel engines- this is a phenomenon that usually only affects liners. But series 60 detroits commonly have cavitated blocks if the cooling system wasn't well-maintained. IMO, this is due to lower quality metallurgy than other brands. This shows up when machining the counterbores in the engine blocks. I can cut four or five Detroit engine blocks with a particular cutting bit. The metal is soft. The same carbide bit will be dulled after only ONE Mercedes block- and this is with less metal being removed than from a comparable Detroit. Also, by comparison, Mercedes blocks NEVER cavitate or corrode the way a series 60 does. That's not to say that the MBE4000 doesn't have more than its share of problems- but the metallurgy is clearly better. IMO, Detroit Diesels are relatively cheap, basic equipment- not unlike Case equipment.
Mercedes is different. I've been very impressed with the fit and finish of mercedes parts- Detroit parts are often embarrassingly crude by comparison. Parts availability isn't that great over here- but that's largely due to their import status. I imagine the parts situation is better on your continent. Their MBE 900 engine is one of the most trouble-free engines I've ever seen. These engines are common in medium-duty applications over here, but we rarely work on them (except when Mercedes came out with a fuel line replacement campaign. I had no idea so many of these engines were out there until they started bringing them in for this fix). It’s just that they rarely break. IMO, it would be hard to find a better medium-duty engine than the MBE900 (we're talking pre-2007 here. Lots of things changed in 2007).
The MBE4000, on the other hand, has been a constant headache. IMO, this is due to some of the most arrogant and unresponsive factory support that I've ever dealt with. For example- in all my years of working on diesel engines, it’s been exceedingly rare to see an injector line just break for no apparent reason. When I worked at Cummins and Deere, we NEVER torque these with a torque wrench- just snugged them down with a wrench and that was it- I’ve no doubt that we ROUTINELY over-tightened these lines. But they NEVER had any problems. Contrast this with the MBE4000 injector lines. From the moment that the MBE4000 was introduced in Freightliner trucks over here (around 1998), these injector lines were routinely breaking. Trucks were often towed in for this… [censored], some of them burned down because of it. And year after year, Mercedes came out with one service bulletin after another essentially blaming the problem on mechanics who weren’t properly torquing the injector lines (despite the fact that these injector lines were often failing directly out of the factory- no mechanic involved until after the failure). They came out with multiple changes in torque specs, verification stickers, etc. It wasn’t until TEN YEARS after the MBE4000 was introduced to the States that Mercedes finally redesigned those injector lines. We’ve retrofitted dozens of these engines over the past year or so, and this new design has entirely eliminated the problem.
A similar episode that demonstrates Mercedes' factory-support mentality was the MBE4000's problem with leaking head gaskets. Since this engine was introduced, they have ROUTINELY leaked from the head gaskets. Actually, the coolant leaks up around the liner flange shim (which is the ONLY thing that seals coolant at the top of the liner), then out around the steel head gasket (not from the rubber coolant seals in the gasket). Every single other make of engine that I’ve ever dealt with has used some form of redundant seal at the top of the liner. Cummins 855’s and N14’s, for instance, seal the top of the liner with both brass shims and a press fit- they also use a steel gasket similar to Mercedes, but don’t suffer from the same leakage problems because of this redundant seal. Series 60 detroit engines, John Deere engines, and C-series Cummins engines all seal the coolant with both a liner shim and a soft head gasket. Again, they rarely suffer similar leakage problems. So the cause of this MBE4000 problem was OBVIOUS. But rather than address the problem directly, Mercedes made multiple re-designs of the head gaskets and cylinder heads… none of which directly addressed the problem or helped the situation in the slightest (in fact, the new style head gaskets only INTRODUCED problems). For YEARS, they started simply replacing the entire engine rather than address the problem- I’ve replaced quite a few of these under warranty, myself. Finally, ELEVEN YEARS after they introduced this engine to North America and started encountering this problem, they redesigned the liners. They put a redundant seal at the liner flange- an o-ring in addition to the shim. I’ve retrofitted probably a dozen or so engines under warranty, and this has completely fixed the problem.
So this has been a LONG rant. In conclusion, my impression of Detroit engines is this: Cheap, simple, not the best quality. Mercedes: EXCELLENT quality, but extremely slow or nonexistent response to even the most obvious design flaws.
Now, the series 60 engine is going to cease production as of 2010, I’m told. So Detroit Diesel will be selling only the DD15/DD13 (which is a re-badged, overhead-cam Mercedes). Can’t say how it will hold up over time, but I was very impressed with the design and (apparent) quality of the engine when I took a DD15 overhaul class. While it is similar in several ways to the MBE4000, all of the inherent problems that I’m aware of in the MBE4000 have been either addressed, or more often eliminated entirely in the DD15 design. If this engine proves to be as bullet-proof as the MBE900… I may be out of a job. They may not need fixin’.