'There has been a lot of discussion on the virtues of a engine used in a RV lately. This is just my opinion of engines and perhaps I am biased from years of standing in the service departments of retail automobile dealerships, interacting with owners of products that were not well thought out.
Any one out there remember the 4 cyl in the Vega? The fuel system Cadillac used in '81 on a perfectly good cast iron engine. The 8-6-4. The 4100 aluminum engine rushed into production in '82? The 4 speed transmission in the late 70's/early 80's GM product line with the sheet metal clutch packs?
Are some better than others, Yes. It starts in the design stage, then goes to the casting plant, the selection of other components, pistons, head gasket material, bolt sizing, are the rods and crank forged or cast. Cooling system designs are just part of the mix.
It goes back to Corporate thinking about how much to spend on R&D and what Corporate expects of a power plant. What is Corporate thinking about how to handle problems that show up in the field.
Some Company's come up with a design that is flawed, and due to the thinking at Corporate, the design is not changed, or if it is changed the original design issues are just passed on to the next generation.
GM, in 2001, partnered with Isuzu to develop the 6.6L in use today. It took a 4 year learning curve but today it is a pretty decent engine. Looking here you can see the learning curve. http://en.wikipedia.org/wiki/Duramax_V8_engine
A example of GM's thinking is reflected in the drive train of the '04-'07 Saturn. They bought the Honda 3.5L drive train that Honda used in their Van and Pilot SUV and dropped them into the Saturn Vue. Corporate knew they had to start outsourcing.
International developed the 6.9L in '78. Ford used it from '83-'87. In '88 it was bored .11" and the 7.3L was born. Same engine just more CI. Ford used it till '94. In '95 the "Powerstroke" was born. Same base as the 7.3L just had electronic injection added. In '99 a turbo was added. The same base engine was used until emissions killed it.
Dodge, also turned to a respected engine manufacturer, Cummins. They used the 5.9L until emissions forced the 6.7L to be developed.
Both Ford and Dodge knew they should rely on vendors that were experts in their field.
GM did not understand this fact. They did and presently make a pretty good group of engines, but diesels were not their bag. It took the competition of others to make them see their faults.
In a previous post, Detroit Diesel was mentioned. Detroit Diesel was a venture between Detroit Diesel Allison Division and Roger Penske formed in '88. They were never involved in the GM diesel engines used in light duty trucks of that time frame. http://www.detroitdiesel.com/about/history.aspx
As usual your opinions and experiences may differ.
Respectively, Jim
Retired Service Manager '72-'96
'96 Sahara 3540, 300 CAT, 520 W solar'