No manufactures do design the heads and water jackets to allow the engine to reach thermodynamic effeciency faster then in the past but that is not all bad. What I mean is that so long as you maintain the cooling system and use a decent oil all is well. They have gone to better meaterials, less tolerance stacking and more uniform methods of forming the parts. They use different casting methods for different propeties that a given part needs, powder metal, cracked caps etc.... Do not get me wrong forged is still the best and cast iron is still a great meteaterial but we have MPG targets the need to be meet and their is emissions that have to be meet. So it is give and take... I would say that engines today are cleaner then they have ever been are just as durable as say late 1980's engines but produce much more power on less fuel with lower emissions. Some durablity is lost by some manufactures but not across the board. For instance Toyota's engines especialytheir V8's have to be amoung the finiest in production vechiles on this earth and have to be more durable then any other production mass produced V8 in vechiles costing less then $50K in the history of the internal combustion engine! On the other hand we have seen some designs from some OEM's like GM that are neither a step forward or a step backwardsin terms of durability or refinement but are produceing great power output with managable emissions and better fuel economy then they had in the 1980's!
Baring the slant 6 from Chrysler Toyota and Honda preety much set the standard for reliable durable long lasting engines and transmissions it was body rust that they had to learn to control.It has been the norm since the late 1970's for Toyota's to routinely go 300,000-500,000 with nothing but routine maintenance and that was back when 120,000 on a domestic vehicle was thought to be incredable!Today many manufactures have designs in place that will easily do 300,000 with routine maintenance it is normally the transmission that is the weak link today as soo many people are driving automatics and rubber seals,check balls and electronic solenoids just can not match the durability of a good manual trans.
Most of Toyota's modern engines can do the 500,000 mile miracle, I have little doubt that Fords Modular V8's can do almost as well as a Toyota V8 in terms of real world durability.
I do see todays oils as less then what they used to be but for me that is because M-1 had to drop their additive levels to meet SM levels. I think any oil that has an additive package that isnot on par with a diesel oil is basically a weak knee'ed oil and not worth putting in your car. The only conspiricay is that GM is cheap and makes cheap catalytic converters that plug up easy and often due to their engines burning so much oil. With all the money they spent on the North Star for instance you can not tell me they did not know they drank oil like a kitten drinks milk before they released that design. Same thing with their modern short block's and the oil consumption and piston slap issues......Really you are telling me that none of the captured fleet vehicles had these issues during validation? So what you really have to ask yourself is why some companies have so many issues with oil burning, plugging catalytic converters and such that they needed to create a new oil standard to try and cut warranty cost. You have to follow the squeaky wheel! The company screaming the loudest is usually the reason for a new standard. Since most of GM's engines use roller lifters lots of anti-wear agents are not needed. The other companies I am sure also thought that the possibility of lowered emission warranty claims was also a good idea. GM has been hit hard for a long time by states that have California testing and emissions....They where and I am sure still are geting it hard because of CARB. GM has had a lot of black eye's when dealing with CARB over injector problems, EGR problems and catalytic converter issues. CARB can afford to hire the best engineers and lawyers around to prove that GM or any other manufacture put a defective design ont he market and they make them warranty it. For example some of you might recall the quasi MPI unit GM had ont he V6 and Small Block that had a central port injector with 6-8 tentacals coming off it with a popet valve on the ends. These would carbon up and fail. Carb proved that they knewit was a defective design and that the fuel pump design was also sub par. GM settled with CARB by agreeing to warranty theses untis which often needed to be decarboneed or replaced every 50K to pas emissions for the next 300,000 miles and to design and retrofit those units at a latter date with an improved design! So it made sense for Bob Olree(sp) of GM to try and get lowered additive levels as well in the oils as a means of reducing their warranty cost. It was cheaper to get a new oil standrd thenit was to redesign all their engines to not burn so much oil. I mean you had a lot of designs if you included Cadaliac, Saturn and the rest of GM that burnt a lot of oil. The more oil you pass through the exhaust themore ZDDP that pass through the cat aand the quicker it is ruined. Lower the additive levels and you extend the life of the catalytic converters.
So it was not a conspiracy to make engines wear out faster it was a conspiracy to get around spending more for a better engine design or catalytic converter.Just like the higher head temp.'s OEM would love to not do that but in order to pass emissions easily it is a must. Just like sticking cat's on the exhaust manifold right under the hood next to all the other engine components not something most OEM's wanted to do! It waas the easiest way to get the cat's hot fast so they light off and start doing their job.So it is normaly some guy in a suite in Washinton or some tree hugger in California that is responsibly for things that make engines less durable or more complex then they need to be!
