Diesels are different Chapter 6

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Diesels are different Chapter 6

Diesels are different Chapter 6


From my “Truck Nuts” book. Diesels have generally twice the compression of a gas engine and require compression and heat to explode diesel fuel. This requires diesel engines to be built heavier than gas engines that use spark to ignite gasoline. The exploding diesel is one of the reasons diesel engines are louder. High compression in a diesel creates the heat needed for combustion but for fast starting truck manufactures heat the fuel and air going into the engine. Ford Power Stroke uses glow plugs in each cylinder; GM Duramax diesel has glow plugs and an intake manifold heater. Dodge Cummins diesel has an intake manifold heater to help start the engine. Glow plugs warm up the cylinders before the fuel gets there and a manifold heater warms the air going into the engine.

For glow plugs and manifold heaters, the indicator light is in your dash. You want to wait until the indicator goes out before starting the diesel. After you drive it and it’s warm and you shut if off and restart it while the engine is still warm, wait for the light to go out then also. It will cycle shorter when warm (shut off sooner,) but your glow plugs will last longer if they are off when your engine explodes the fuel. If it doesn’t start right away I would cycle the glow plugs again, especially when new.  When a diesel is new it doesn’t always start right away. This will get better after it’s broke-in. The important thing is not to start the engine with the glow plug still on and use them each time you start the engine. But if the glow plugs are still on and you start it, the red-hot glow plugs are getting the force of the exploding fuel. This will prematurely wear out the glow plugs. They should normally, the glow plugs and the solenoids that control them, last over 100,000 miles. I figure if 90% of the ambulances are diesel and they can wait a few seconds for the glow plugs to go out, I can too.

It will realistically take 5000 miles to break in your new diesel engine. You can pull a trailer after 1000 miles, but the diesel will start faster, get better fuel economy and run smoother after 5000 miles. Read your owners manual, about the break-in period, which is generally 1000 miles. Engines are ran-in while on the engine stand and the oil changed before they go into your truck. This is why your first oil change is the same interval as a normal oil change. In the old days the engine was ran-in (broke-in) by you and you needed to change the oil at 500 miles. During your first 1000 miles you need to vary the RPM’s, (don’t use the cruise control.) This allows the rings and valves to seat properly through out the RPM range and not leave any ridges. New trucks have learning computers. They will actually adjust to how you drive. Which means they will have more power when they are past the break-in period and if you want them to say shift at a higher RPM then you need to accelerate more when you drive.

If you live in cold country I sometimes run the glow plugs twice before I start the engine. If you have below 10 degrees winters, you may want to plug in the engine block heater that comes with the truck. I used a $12 plug in timer from Wal-Mart and just have the block heater turn on for 2 hours before I needed the truck in the morning. Because water condenses in your fuel tank, especially in cold temperature, keep you fuel tank over 1/2 full in winter. You’ll need to drain the water out of the fuel filter once a month in winter and less often in warm weather. Check out your owner’s manual for more details.

What do you need to know about diesel fuel, winter, maintenance, and emissions?

Be sure you are using blended fuel, #2 and #1. Normally diesels run on #2 diesel. #2 has lubricating qualities that make it oily, smelly and stays on your hands for a few days. #1 diesel is like kerosene or jet fuel and less oily, less paraffin wax. The lubricating properties in #2 are what gels when extremely cold. This is why a blend of #2 and #1 50/50 is used in the winter by most service stations in states that get cold. But if you go to a warm state, (California, Arizona, Florida, etc,) in the winter and buy fuel there before coming home, you may want to use a diesel additive. If you are out of your area, buy your diesel at a truck stop. They should know what you need.

If you have never experienced gelling up a diesel in the winter, be happy. I have had this experience on my farm tractors. I had to use a hair dryer to liquidify the fuel in the injector pump and then “crack” the fuel lines to bleed the fuel through the pump and injectors. Most states don’t get cold enough to plug in the block heater on your diesel. But if you are in the colder areas and need to plug in your diesel, I like to use a timer you can buy from Wal-Mart for $12 to $15. You only need to set the timer to turn on for a couple of hours before you’re ready to use your truck.

Oil changes can cost two to three times as much or more than gas trucks. In area’s where you are required to have an emission test on trucks, the diesel emission test costs more and sometimes is required more often. In Colorado you get 2 years emission exemption when the truck is new and after that you are required to be tested every year in certain Front Range counties.

Diesel is safer to handle than gas as far as fire. With the new turbo diesels, smoke is not the problem it use to be before turbo’s. Because diesel has to explode to combust, the engine components are built heavier than gas engines. But the diesel mechanic rate per hour is higher than for gas engines.

Most of these diesel engines have a bleeder valve on or near your fuel filter to drain off water from the fuel; diesel engines are prone to condensation in the fuel tanks. Semi-tractor trailer rigs have dual large fuel filters, air filters and air dryers. If you pay close attention to servicing your fuel filter, air filter, oil, oil filter, and radiator service at the right intervals you should expect to join the 300,000-mile club with your diesel pickup truck.

Warming up and cooling down, I would also recommend getting the diesel to operating temperature when you drive it. I would avoid short trips where you turn it on and off without reaching normal operating temperature. Getting the diesel engine to operating temperature burns off the water condensation in the engine. Avoid prolonged idling too as it will build up carbon inside the engine and shutting off the engine after prolonged idling can glue that built up carbon to the engine. It’s also wise to get to operate temperature before pulling heavy loads. Most of the turbo’s in modern engines rotate on bushings not bearings, so if you shut off a hot engine under a load there is no oil pressure oiling the bushing in the turbo while the turbo spins to a stop.

Diesels are designed for long life and power from low RPM torque. If you take care of them, you can expect 250,000 to over 300,000 miles. You need the first 100,000 miles to pay for them. Diesels are addicting, enjoy them!

Competition from around the world has greatly improved our American cars, now it’s time for trucks to greatly benefit from that competition. Just look at how much improvement we’ve had with diesel trucks since 2001 when GM woke up and joined the race with the Duramax. Just think what horse trailers would be like if there were only 3 brands instead of 80 plus.

#2 diesel

From what I know and I live in Colorado and have used diesel fuel for 30 years, their is no difference between farm fuel and road fuel. I’ve used them both in diesel trucks. Yes taxes are different (no road tax on farm diesel) which reflects in price and that alone is why the dye is added to farm fuel. The fine, last time I looked was $10,000 for using farm fuel, which can be #1 or #2 or blended. Farm tractors are no fun to clean out after they gel up either.

#2 diesel has paraffin in it like wax and lubricates better. In the winter #1 is blended in cold state services stations. because #1 doesn’t have paraffin and doesn’t gel. (turn to jello) #1 is very close to kerosene and jet fuel. On a feed lot I worked at decades ago, they had two Ranger Jet helicopters and one of the senile owners would run low on fuel and I’d put #1 diesel fuel in it. Your diesel engine wouldn’t last as long if you ran #1 year round.

Yes indeed, diesels use very little fuel at idle allowing truckers to keep the truck running while they nap. And the carbon buildup in a idling gas engine is not conducive to long life. But the soot in a diesel engine will also build up harmfully if you shut of a diesel that has idled long only. In Europe diesel passenger cars make up over 40% of the vehicles verses our less than 1%. In Spain you can buy a Ford Focus diesel. In this country with VW offering an economical diesel car for a couple of years now but not in all states, as well as in 2005 they will have a 5.0L V-10 diesel available in the SUV Touareg. Europe is on the path that diesels are the future to economy and lowered air pollution, while politics in this country are toward, alternative fuel, and hydrogen cells. Actually the engineers I interview think it’s impossible to make the hydrogen cell save enough. VW has a major project underway with biodiesel, biomass called SunFuel, which will complete the circle with only C02 emissions going back to the plants that to produce more biomass. I not against diesels, I just don’t think they fit every scenario nor do I think everyone needs a dually to pull a horse trailer.

In the old days, some of the semi-trucks I drove had “cool-down” instructions on the visor. And those instructions listed how long to cool down the turbo before shutting off the engine and why. But those old trucks had a primer valve on the dash too, to build up fuel pressure before the glow plugs.

I’ve listened to Cummins diesel experts, that I trust, give speeches on not needing to cool down modern diesels for long turbo life anymore.  But most turbo’s have bushings instead of bearings in the turbo, (Garrett does have a ball bearing turbo developed with ATS) and when the engine stops, the oil to the bushings stops pumping. I know that by the time you stop at a few lights, turn a few corners, slow down for the dog, that the engine could be cool enough to shut off. I also notice that the new 2004.5 Dodge Cummins has a new oil reservoir built in the bushing cavity of the turbo. So someone at Cummins thinks you need to keep the turbo bushings running in oil too after the engine is shut off.

Another example of a truck manufacture wanting those turbo bushings to cool off, is the GM Duramax. Their Borg Warner turbo has a water jacket built into the turbo housing to circulate water to cool the turbo. With the physics of hot water meeting cool water in the engine, keeps the water flowing thru the turbo even after the engine is shut off.

So it certainly can’t hurt to cool off a diesel, especially when pulling that trailer that’s a little too heavy. Diesels are very economical at idle. I don’t think that excessive idling of a diesel can be that good for it either, though we all see over-the-road trucks idling for hours at truck shops. But you don’t see them idle for hours and then shut off the engine. That’s how you glue soot to a cylinder wall. And that’s what an ole farmer thinks about that.

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