a very interesting post about a car i've always flirted with getting.
On 11/18/05, Smith, Todd <[EMAIL PROTECTED]> wrote: > > Hello, > > This is one area that I know a little something about since I have > followed these diesels for years. In the early 70's, GM was looking at > worsening fuel prices and their existing production lines for large > automobiles and declining sales. The Oldsmobile division spent time and > money looking at ways to improve fuel economy in their larger automobiles. > One promising avenue was to design and build a diesel engine with the BPOC > (Buick, Pontiac, Oldsmobile, Cadillac) transmission bolt pattern that would > bolt up in existing production lines. > > AFAIK, in 1974 Olds was testing a diesel engine that was built from an > 5.7L Rocket spark-ignited gasoline engine using a belt-driven IP. These > tests were a complete failure and Olds realized that they couldn't use > anything more then just external accessories from existing engines. > Everything else for the new diesel engines had to be custom designed > including the block. The myth that the later 5.7L and 4.3L diesels are > converted gas motors is completely false. The blocks have a higher nickel > content and 4 bolt mains and a different crank size then the small block > Olds gas motors. > > The engines used two different types of injectors, pencil and poppet types > that while custom spec'd for this application were derived from agricultural > use injectors. These are supposedly far more efficient designs then the more > typical Bosch style injectors that are in widespread use. In 1982, EPA > testing showed that the 1982 Oldsmobile 98 full-size car was getting 32mpg > on almost a 5000# car. These engines were available across the entire GM > product line from 1979-85 and still to this day rank 4th on eBay as the most > numerous diesel passenger vehicles. > > Why do this engines have a terrible reputation and why did GM drop the > whole project and buy third-party diesel designs? There are many answers and > the truth is probably some of all of them. The biggest issue that the > engines had were in head gasket failures since they seemed to fail much more > rapidly then other gas engines of the same time frame. Another answer is > that these engines were designed for fuel economy and not horsepower and > owners tried to expect too much from the engines. A third answer is that in > the early 80's diesel fuel quality was said to be at a all time low and non > diesel savvy owners would buy diesel fuel in places where the fuel had been > contaminated via water or algae. > > The head bolts were installed by some early robotic equipment using > stretch to torque fasteners. These fasteners were not adequate to the job > and most believe were primarily selected due to compatibility with the new > robotic equipment. The head bolts were not adequate for the task and > routinely failed causing head gasket leaks in as few as 30-50K miles. In > some cases, 100K were reached, but many didn't reach that point without > failure. GM didn't take the time to properly research the problem and for > the dealers, it was faster to replace the entire motor then troubleshoot the > dead one. Dealers hated to deal with the vehicles due to the constant > service issues and customers hated the vehicles since the problems didn't > stay fixed. > > One issue with the head bolts were they were designed to be one use only > applications. Either through neglect of training or not caring enough, many > GM technicians would reuse the fasteners that "looked" okay and only > replaced the "failed" bolts. Of course, it wasn't long before the head > gasket failed again and the engine was blamed to be a poor design. Replacing > the head bolts with solid ARP aftermarket fasteners has resurrected many > Olds diesels. > > The website http://www.olds-diesel.com is a good source of information > concerning these engines and the automobiles that they were installed in. > Many fixes and improvements over factory original have been made and many > users drive "transplanted" engines in vehicles. One of my personal favorites > is the Diesel Fiero that is running the 4.3L V6 diesel. > > Todd Smith <[EMAIL PROTECTED]> > > _______________________________________ > For new parts see official list sponsor: http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://striplin.net/mailman/listinfo/mercedes_striplin.net >
