Aug 22, 2014
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In the Shop

RSS By: Dan Anderson, Farm Journal

As a farm machinery mechanic and writer, Dan brings a hands-on approach that only a pro can muster. Along with his In the Shop blog, Dan writes a column by the same name as well as the Shop Series for Farm Journal magazine. Always providing practical information, he is a master at tackling technical topics and making them easy for all of our readers to understand. He and his wife, Becky, live near Bouton, Iowa.

More On Matching "Loading" Of New Tractors

Aug 20, 2014

 In my last blog I commented that extensive idling or "light loading" of modern diesel tractors can lead to problems with the exhaust emission control syestem. I mentioned that tractors that use diesel exhaust fluid (DEF) need to be worked consistently and "hard" so their exhaust systems will work properly.  Kenneth emailed me and noted that it is more correct to say that tractors with a diesel particulate filter (DPF) need to be worked hard in order to keep their exhaust systems operating correctly.

He's right. The short, simple explanation is that Interim Tier IV and Final Tier IV engines that use a DPF in their emission control system can develop problems if they idle at low rpms for extended periods of time, or if they are run at high rpms at light loads for long periods. Those engines need to be worked hard enough to produce enough exhaust and coolant heat to make the emission control system work properly. 

Before I put everybody, including myself, to sleep with all this Interim Tier IV, Final Tier IV, DPF, DEF and other gobbledy-gook, let me sum it up this way: If your new tractor has a really complicated-looking exhaust system on it, it would be in your best interest to try to use that tractor in ways that make it grunt at least a little. Either size the load to make the engine "work" more than half the time, or shift up and throttle back when the tractor is dealing with light loads, so that the engine is forced to work harder and build the exhaust and coolant temperatures necessary for the emission control system to work properly.

The owner's manual for tractors with Interim Tier IV and Final Tier IV engines should have detailed guidelines on how to keep the new engines "happy."

No More Over-Powered Tractors With Loaders

Aug 16, 2014

 The technical explanation is long and complicated, but the short version is that it's not going to work well to put bucket loaders on big tractors that use diesel exhaust fluid (DEF). Nor is it going to work to put a high-horsepower tractor on a windrower, a pull-type sprayer, or possibly on a grain cart.

The issue is that engines that use DEF need to be consistently loaded for the DEF system to work correctly. Running a DEF engine at low to moderate rpms a lot, or running a DEF engine at high rpms at light load, doesn't generate enough heat for the DEF system to do the things it must do. If DEF engines run too cool, too long, they go into "regenerate" mode more frequently than is optimum, which can lead to problems.

DEF engines need to be worked hard. That need is starting to show up on dairy farms where DEF tractors are used daily, at moderate loads, for choring. It may show up this fall on grain farms when large-frame DEF tractors are attached to grain carts that idle or run at mid-range rpm for days at a time. 

Talk with your salesman and mechanic before buying a DEF-equipped tractor to ensure your needs and the tractor's needs are in sync. 

Combine Considerations

Aug 13, 2014

 Unless you're one of the unfortunates who flooded-out or hailed-out last spring, you're probably looking at a bumper crop to harvest this fall. You're also looking at low grain prices, so there's a temptation to cut back on expenses in anticipation of lower profits. I've already seen customers scrimping on combine repairs and maintenance, but in view of the extra bushels combines are going to have to digest this fall, avoid the temptation to:

-scrimp on belts. If a belt has any cracks at all, if it has any burned, glazed or questionable areas, replace it. It won't make it all the way thorugh the upcoming bumper harvest.

-stretch augers and auger housings, "one more year." Any auger flighting that doesn't still have a square edge to its flighting, or has a "wobbly" pattern worn into the outer half of the flighting's wear-surface, is going to be completely shot by mid-harvest. Check all auger housings by tapping them with a small hammer. If they dimple easily it's a sign they're worn thin, and they're going to wear through by mid-October.

-ignore worn clean grain elevator systems. The entire clean grain system--from the lower clean grain auger, through the clean grain elevator conveyor chain, to the grain tank loading auger--is prone to "domino damage" because if one component fails it causes problems for all the others in that system. Don't replace a worn elevator chain without considering if the clean grain auger and loading auger also need attention. 

-pretend you don't hear funny noises. Start the combine up and run it for at least 5 minutes at full rpms with the header, feederhouse, separator and unloading system engaged. Have someone sit in the seat while you walk around the machine. Don't assume any odd clanks, bangs or screeching will go away once the machine "gets warmed up." They won't. 

No harvest is "easy," but this one is shaping up to be a challenge. Maybe, with some extra attention before you begin, it won't be any tougher than average.

Diesel Exhaust Fluid, Friend AND Foe

Aug 09, 2014

 You don't have to like Diesel Exhaust Fluid (DEF), but you're going to have to accept it. In order to meet Environmental Protection Agency regulations, many engine manufacturers are using Selective Catalytic Reduction (SCR) systems to reduce diesel exhaust emissions. Injecting DEF into an SCR exhaust system is one of the steps to reduce diesel exhaust fumes to a level where they are purportedly cleaner than the air in downtown Los Angeles on a smoggy day.

So here's the good news about DEF, aside from its benefits to the environment: When everything is working correctly, all you have to do is keep the special DEF tank filled. Computers and components do all the rest. The operator just has to tune in their favorite radio station and drive.

But here's the bad news about SCR/DEF systems: they are EXPENSIVE. We're talking about tens of thousands of extra dollars added to the purchase price of a truck or tractor. For you truck drivers for whom weight is an issue, I'm told that SCR systems add a thousand or more pounds to the base weight of the truck, therefore reducing your potential legal load capacity. There's also an initial "get acquainted" cost of adding DEF storage tanks and transfer pumps for anybody who purchases a machine that requires DEF, because DEF requires special tanks, special pumps and sanitary handling practices. Everything is cool after those initial costs--until something goes wrong with the SCR system.

There are two costs associated with repairing a malfunctioning SCR system. The first is the cost of components, There are a lot of computers, sensors and specialized gadgetry on SCR systems. With sensors costing $150 and more each, and the main catalytic converter retailing for more than $10,000, it can be expensive to replace failed components. Then, there's the cost of diagnosing and physically replacing failed parts and pieces. It's going to take mechanics a couple years to learn the tricks and shortcuts to diagnose and repair SCR sytems.

So, the good news is that most of the time, SCR exhaust systems will operate seamlessly in the background, once you get past the initial purchase price(s). But hold onto your wallet if something goes wrong and repairs are required. Mechanics don't like it any more than you do, but it's the law, so we might as well get used to it.

Concerns About Combines

Jul 26, 2014

 We've still got to get through August, but things are looking good across the Corn Belt for a mega-corn crop this fall. There are pockets of hail damage and flooding, and we sympathize with those folks, but many of us are looking at the potential for a huge corn crop.

That means combines are going to handle a LOT of bushels. High yields magnify weak and worn points in combines. To minimize breakdowns, here's a quick list of wear points common to all combines, that should be checked before harvest:

-Feederhouse floors and conveyor chains. Tap the sheet metal of the floors from the bottom with a hammer and replace/repair if the metal dimples. Replace conveyor chains if there's more than 1/16-inch of "slack" between links when they're squeezed together with slip-joint pliers.

-Check feed flights on threshing rotors, rasp bars/threshing elements, and concave thickness. Even though those components aren't worn beyond replacement recommendations, consider replacing them if they're "close" to replacement, to maintain good feeding and threshing all the way through the end of this mega-harvest.

-High yields put extreme stress on clean grain loading systems. Make sure the lower clean grain auger is at full diameter, that the clean grain elevator chain paddles are full size, and that the grain tank loading auger is in good condition. If each of those clean grain handling components is slightly worn they allow grain to back-feed to some degree, and that back-feeding multiplies drag on the system and increases wear which increases back-feeding...and things go downhill rapidly after that.

-Straw chopper knives need to be sharp. Many people have a, "who cares as long as it spits stuff out the back" attitude toward choppers. Two things to consider: dull knives are a huge drag on horsepower, and dull knives don't chop and spread residue well. One engineer told me dull knives can steal 25 to 50 extra horsepower. And an agronomist told me that uneven residue distribution in the fall is a major factor behind uneven emergence of next year's crop.

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