Prevost with a Volvo Engine

[Jon Wehrenberg]

I'm not an expert on emissions, or what constitutes clean exhaust compared to dirty exhaust. I fail to see the logic in taking a diesel engine (SS60, DDEC III) that could deliver 8.0 MPG in our buses and in the process of making the exhaust cleaner (SS60 DDEC IV and above)make it burn more diesel.

In 1968 or thereabouts cars were forced to meet emission standards and it is only in the last decade that we are seeing not only clean engines, but engines with more power despite getting fantastic mileage and long life. During that 30 year time frame between when the standards were introduced and the real start of clean engines with real power our cars were strangled with air pumps and all sorts of interim measures that robbed power and increased fuel consumption.

I think the single greatest technological change that made our engines what they are today is the widespread use of very sophisticated computerization that can literally deliver the correct fuel/air mixture on every compbustion stroke.

I don't doubt diesels can make the same progress, but I think what we are seeing today is the repeat of the early emissions gas powered engines where add on features are required to meet the standards. Maybe 10 or 20 years from now diesel engines will meet the standards without any external devices or power robbing controls, but until we get there I think we have seen the last of good mileage and relative simplicity in the engines. I just wonder how truckers are going to impact what is happening. Right now truckers have access to all sorts of program mods for DDEC to give substantial power increases and unless and until the current crop of engines is built so they cannot be modified I think we can expect to see owners start modifying their engines. In the 90's a lot of Prevost owners were bumping up the HP in their 8V92 engines and we may be seeing a repeat of that.

But in the meantime I am going to try to figure out how less MPG equals good. It must be the tree huggers have one set of needs and they are in confict with those who want energy independence. The tree huggers won this round.

[Mark3101]

It is not just the lower MPG, but also a decrease in oil change mileage intervals and the associated waste from those. I couldn't understand any of this either...go down in mileage, change oil more often and often times have emission related issues all in the guise of being "clean". Also, engine life has gone way down in the quest for "clean". Before the EPA got their fingers more deeply into diesel emissions, we could regularly run Caterpillar 3406 engines between 800,000 to 1,000,000 with little expense or work other than maybe rolling in a set of bearings and change out the fuel nozzles..things that were not terribly expensive. Each time the EPA had a hissy and mandated more controls, miles to complete overhaul went down and expenses went up. Granted, this was the time frame that also brought us electronic engine controls and the good things associated with them, but the overall cost has still not come down to where it used to be in regards to maintenance.

That is one reason why you sometimes see so many late model trucks sitting on lots...many people just lease or trade and turn them after 2 or 3 years and do virtually no maintenance. The exception to this trend was the delays many made in purchases waiting to see how bad the 2007 and especially the 2010 emission changes were going to be...DPF and Urea being the big ticket items that come to mind.

[phorner]

This kind of reminds me of the time when the government was starting to mandate passive seat restraints and air bags in cars.

The auto manufacturers purposely designed, built and sold those horrible shoulder seat belts that were attached to the door and (hopefully) retracted when you closed the door. They knew the public would complain and complain loudly. This was an attempt by the auto makers to get the public to pressure Big Brother into delaying the required start dates for air bags.

This is NOT speculation as this sorry episode has been well documented. The auto industry was trying to save money and push regulation off as far as they could. The additional expense of adding air bags was considerable.

So, it is not beyond possible that engine manufacturers are playing similar games regarding emissions, and the cost of compliance, too.

[johnklopp]

Additional photos from Perry.
There are a total of 4 belts but it looks like a lot more.
Coach has not been deliverd to converter.
Other options for number and type of alternators avaliable.
This one was at the request of "Marithon"

[Kenneth Brewer]

Is the top photo of the driver's AC compressor on the extreme left? Is the air compressor gear or belt driven (don't see this at all right now)? Just curious about what I see in the photos. At the moment I think Jon is right, 8 belts; 4 separate pulleys on the main crank, one of which is a double belt and the other 3 are serpentine, and two pulleys on a separate shaft (driven by the double on the main) to the right, one of which is a double belt. Total; eight.(?).

[johnklopp]

Belt label from engine compartment

[rfoster]

Reminds me of an Allis Chalmers Combine--- an old one that we pulled with a "M"Farmall.

[Jon Wehrenberg]

I'll stand by my count of 8 belts. The diagram does not reflect all the accessories or count the two dual belt drives.

Regardless that's still a complex set up.

[johnklopp]

You are correct Jon. I simply counted the belts shown on the diagram, I hate it when that happens.

[travelite]

John,

Thanks for the photos. Fascinating!