Finals & The End Of Semester

This past week we took our finals which included a written and a hands-on portion. Out of two teams of students, each team wrote the final which the other team would take. The hands-on portion was devised by the instructor.

Following our final we talked to some high school kids who stopped by on a field trip about the Auto/Diesel program and the Automotive/Diesel repair business. Maybe we will see some new faces in our shop soon!

Note: I cannot post up the media I have for this blog post, as not everyone was able to take their final last Thursday. I will edit this post to include it after tomorrow.

My reflection:

I learned a lot this semester. Not only about diesel fuel and hydraulic systems, but also about teamwork, getting along with your colleagues, and dealing with the unexpected.

The lessons I have learned this semester will serve me well as I seek employment in a real shop, especially those lessons about being a self-directed learner and taking the initiative for our own education and engagement. This is an essential skill on the shop floor when you have to figure things out for yourself.

I have found this blog to not only be a useful way to record and document my experiences in the shop and in class, but also a way to reinforce those lessons by writing about them in my own words.

I would like to thank my fellow class mates, my team mates, and of course my instructor, Jeffrey Starkey, for a productive and educational semester! I look forward to next term, and what can be learned both in and outside of our school shop.

Series 60 Overhead Adjustment

This week our Thursday class was cancelled due to Thanksgiving, so with permission from my instructor I have used Tuesday's class for my weekly blog assignment.

Tuesday's class is Diesel Engine Service and Maintenance, where we have learned the basic operating principles of a diesel engine, as well as service procedures.

This week we did injector and valve adjustments. The procedure is simple, first the engine is barred over until one of the cylinders is on valve overlap. Once we have a cylinder on valve overlap, we refer to our service information to determine which cylinders require which adjustments. On our Series 60 engine, injector height and valve lash are adjusted on different cylinders.

A special injector height tool is used and inserted in a small hole in the injector hold-down clamp. The height tool is of a specified height (ours is 81mm). Once the tool is in place, a flat on the tool is swiped across the top of the injector plunger until it produces a slight drag and wipes the oil off the top. The injector height is adjusted by loosening the locking nut and turning the adjusting screw with an allen head wrench.

Valve lash is adjusted the same way, however the measurement we are taking is with feeler gauges between the valve stem and valve button at the end of the rocker arm. Our goal is to fit the specified feeler gauge (.008" for intake valves, .026" for exhaust valves) in there and produce a smooth, even pull. Too much drag and the valve must be loosened, too little and it must be tightened.

We proceed in this manner until the valves and injectors have been adjusted on all cylinders.

Access is easier with the Jakes off, even though service information recommends leaving them on.

The height gauge for measuring injector height. Note the locating hole in the hold-down clamp, and the flat at the top of the gauge which is swiped across the top of the injector plunger.

My reflection:

Once again we get back to a word every mechanic and technician should be familiar with: accessibility. While it tends to be better on the big trucks than it is on cars, we still encounter plenty of accessibility problems on the rigs too. For instance, according to our service information, these adjustments should be made without removing the Jake brakes (if possible). Removal of the Jake brakes was necessary to gain any reasonable access to the valves and injectors.

Another accessibility issue was injector height adjustment on cylinder #6. Because it is somewhat recessed behind cab parts and closer to the firewall, it was necessary to actually lay on top of the engine to see what we were doing with the height injector tool (as it must be set inside the locating hole on the hold-down clamp to get an accurate measurement).

The same scenario would be encountered if we were to follow procedures to drain the cylinder head of fuel for injector removal, which requires disconnecting the fuel fittings at the very back of the head.

Return to DD13

We returned to our DD13 and removed the rocker shafts. Unfortunately due to us starting late in the semester and having other things also taking up our time, we have decided that rebuilding the DD13 will have to wait for another time.

So we printed out the relevant reassembly service information from Detroit Diesel's Power Service Literature and began reassembling what we took off. Procedure, torque specs, specialty tools, diagrams, and other considerations are outlined in the service literature. And so reassembly could begin.

Removing the rocker shafts.

Injectors being installed in their bores. No, we did not forget the bolt for the hold-down clamp!

Injectors and rocker shafts installed and ready to be torqued.

Detroit Diesel Power Service Literature recommends 36-41 ft-lbs of torque with an additional 90 degrees on the rocker shaft bolts. Here is our torque wrench with the angle ready to go.

My reflection:

The semester is almost over, and although we did not get to finish our rebuild on the DD13, I found that I have learned a great deal about the fuel systems used in heavy truck applications.

I have learned how these systems are designed to operate, and how individual components function. I have learned the differences in these systems as they vary by manufacturer and by model, and the changes made in fuel systems as EPA standards get more stringent.

I have learned how much these systems depend on electronic and electrical circuitry to operate. And finally I have learned some of the procedures used to diagnose and service these systems.

This is not the end by far, even though the semester may be almost over, we have barely scratched the surface of what we can learn as mechanics and technicians. Learning and education will follow us out in the field and will be an every day process wherever we end up working.

Field Trip to Fyda Freightliner

This week we took a special field trip to Fyda Freightliner's new service center in Zanesville, Ohio. We talked to staff including the service manager, general manager, recruiting managers, and we also talked to the technicians. Most importantly the newer technicians, some of which had graduated from our school's own Auto/Diesel program.

We toured the facility including waiting lounge, staff rooms, parts department, and of course the actual shop. We were shown how their shop operates and the trucks they work on.

Welcome to Fyda Freightliner!

Exhaust vent above the chassis dyno. Much easier than the ceiling-mounted exhaust ventilation hoses we use!

The chassis dyno. This can be used to diagnose driveability problems without taking the truck out on the road.

Back lot parking as we exited the dyno room. Trucks everywhere!

My reflection:

One question I posed to one of the younger technicians there was the pacing difference between our training in college versus the training they get as technicians for a Freightliner dealership. The answer? Much more intense, much more involved. That is just the training.

My thoughts? Sending technicians to training is expensive for these guys (and even college tuition for us is no joke), so I imagine it is much more involved than our shop classes. I also imagine only the best are sent to training, those willing to learn and those motivated to advance and grow as technicians.

I look forward to the challenges and opportunities waiting for me in this field.

DT466E and the Old Fashioned Service Manuals

This week not much progress was made on our DD13, instead I helped work on the DT466E we have torn apart right next to it. The cylinder head and block deck were polished, and we used a straight edge on the block deck.

Block deck ready to be straight-edged for warpage.

Cylinder head being polished and cleaned. Brake cleaner helps get the grime off after polishing.

My reflection:

With the advancement of technology the vehicles we work on today are much more complex than they were decades ago. However, the tools at our disposal are also much more complex and can make things a lot simpler.

For our DT466E we have no electronic service information like we do for our Detroit Diesel and Cummins engines, so to find specifications for warpage on the block deck and cylinder head, we had to go hunting in the book, and we were actually unable to find these specifications.

Finding information this way tends to be more time-consuming than using the search function on electronic service information to quickly find exactly what we're looking for. That is not to say that electronic service information is perfect, but it usually saves us a great deal of time looking up what we need to know.

2015 DD13 Rebuild, part 3, and Industry Policy

This week we once again returned to our 2015 DD13. Unfortunately, due to circumstances beyond my control we are way behind on disassembling this engine.

We pulled the remaining injectors with our modified lady's foot pry bar and are ready to remove the intake and exhaust rocker shafts. Detroit Diesel Power Service Literature provides all required steps for removing these correctly.

Our class went on a field trip to Hendershot Performance where we were introduced to a side-by-side and four-wheeler repair shop, where we spent the remainder of our class time talking to the owner about the workings of his place of business.

Still a long way to go.

Service information detailing the description and operation of the camshaft and rocker shaft assemblies.

Removal of intake rocker shaft assembly. Removal of exhaust rocker shafts is similar.

The rocker shaft assemblies themselves as per service literature.

My reflection:

Whether it's a large truck dealership and service shop, an automotive dealer, a mom and pop shop, or a shop like Hendershot Performance, the message we hear regarding issues like showing up to work late, walking off from the job, and cell phone usage is exactly the same.

Among the service managers and shop owners I have talked to, this is non-negotiable policy. It simply means the difference between whether you work there or not.

The issue keeps coming up, but the answer to that question from industry seems pretty clear and simple to me.

2015 DD13 Rebuild, part 2

This week we returned to our 2015 DD13 engine which we are still in the beginning stages of disassembly. The special tool recommended by Detroit Diesel Power Service Literature was unavailable to us, so we had to improvise with a lady foot pry bar, ground down on the back of the head to fit in the small space we had to get into, to gently pry the injectors up. The result? Success.

Our work was cut short by an invitation to another class where fellow Auto/Diesel students were giving power point presentations on the political events of the upcoming election.

#5 injector, ready to be removed.

#6 injector bore following removal of injector.

My reflection:

Everyone has a passion, or something that gets them excited, motivated, engaged, or simply fired up. For some it is high performance vehicles or classic cars. For others it may be sports. This week in the shop, it was politics.

My passion is the work we do in the shop and the career I am trying to make out of it. I find it enjoyable, and love nothing more than to get my hands dirty and fix something on a vehicle. Whether it is an old VW, or one of the class-8 trucks in our shop.

At the end of the day I have a sense of accomplishment doing something I enjoy, and something that is needed by everyone from Grandma to get to the store to the truck drivers that deliver freight across the country. To be able to make a living doing this is an opportunity I am always thankful for. And as always, I am constantly learning!

The Future of Auto/Diesel?

This week we once again did not turn a wrench, instead we invested a little time in the future generation of automotive and diesel mechanics.

In place of our Thursday class, we parked the 2016 Freightliner on loan to us from Matheny Truck Center outside the Arts and Sciences building, and I helped my class mate, Brittany Reed, introduce the truck, and the opportunities available in truck repair as a career path, to several groups of 7th and 8th graders. We also had another truck in our shop and out-of-chassis running engines to show them.

The truck we introduced the 7th and 8th graders to, 2016 Freightliner.

Another truck they got to play around with.

Baby Cummins, 37hp 3-cylinder diesel. They got to start it with a remote starter.

The big brother, Series 600 Cummins ISX. They got to rev it on the way out.

Some reflection this week:

These kids are the next generation of potential automotive and diesel mechanics. They are being introduced to the opportunities of this career path, and how to get started on that path. The level of engagement from these students was astounding. We opened a valve on one of the air tanks and let them find the air leak, which they did very quickly. Some of them had a lot of good and interesting questions.

These are opportunities and ideas I wish I had been introduced to at their age. One can only hope that they will take full advantage!

Cookout in the Shop

This week (following midterms) we had a cookout in celebration of our teacher's, Jeffrey Starkey's, birthday the following day. We cooked up some bratwurst and cube steak sandwiches on a propane grill right in the diesel shop next to our FLD Freightliner. We had some onions cut up and sautéed, ketchup, mustard, worcestershire sauce, horseradish, buns and some soft drinks. And of course cheese!

Food has been cooked and is ready to be served.

Some reflection on our day:

We didn't turn any wrenches this week, instead we spent the class period grilling, eating, and sharing stories in good company. There's a lesson to be learned even here, about the benefits of getting to know those you work with and having a little camaraderie like we did sharing a meal. One day they could be the ones offering their hand to pick you up off the shop floor when you need it. And of course, sometimes a little food and a little bonding, even if just once in a while, can go a long way to making those hard work days go by a little smoother and a little more pleasantly.

Don't expect to see this sort of thing in your English or math classes, we do things a bit differently back here in the Auto/Diesel shop!

2015 DD13 Rebuild, part 1

This week we officially began disassembly of our 2015 DD13. This engine uses an amplified common rail fuel system. Following our midterm which involved tagging parts on this and other engines in our shop, we began disassembly.

Service information was helpful determining how we were to remove the fuel system. The high pressure fuel feed lines running from the rail to the injectors needed to be removed as well as electrical connections. The lines are fitted to the head with a line nut and a bracket. Unfortunately this setup does not accommodate us easy access, much like our coolant line fitting at the water pump on the N-14 Cummins in a previous post, here we once again break out the crow's foot wrench and ratchet.

Following the removal of electrical and fuel lines, the next step is removal of the actual injectors. Detroit Diesel Power Service Literature recommends a special tool be used for this, but we do not have this tool so we are looking into other options.

Below are a few of the pictures I took of the fuel rail and lines, these will aid in reassembly so we know where everything goes.

Valve cover off, getting ready to remove fuel lines.

Loosened the fittings, paper towels help keep fuel spillage to a minimum.

There's the fuel filter module.

Some reflection:

I have always appreciated and been an advocate of service information since the first day I started using it. I have used it extensively in both our school shop and on my own personal projects. Without it, there are many times where we would spend an hour figuring out what we could have had done in 5 minutes, or worse, guessing at something.

With that said, there are certain times when the "text book" approach will not get the job done, or the tool required is not at hand. Perhaps the wiring diagram gives you wire colors which don't quite match what's in the vehicle.

Service information is a guide and a road map, one which usually puts us where we need to be, or very close to it. But we also have to be prepared to improvise, because sometimes we encounter situations where it's simply not in the text book.

It has been one of those weeks.

The International Runs, and Coolant Everywhere!

This week we finished getting our International with the N-14 Cummins running. It was supposed to run last week, but we had a coolant leak in a bad spot which had to be repaired, and we ran out of time in class before we could finish the job.

With our International finally running and out of the shop, we moved upstairs to bring one of our out-of-chassis Caterpillar engines down, the results of that and a bit of reflection about that project are posted below.

Additionally, we took a look at our 2015 DD13 which is needing a rebuild. We have had this engine for some time but have only now had any time to even take the valve cover off and take a look. I have also gone ahead and printed out service information pertaining to the removal of the injectors which will be our first step.

Now, returning to our Caterpillar engine...

Coolant everywhere!

Drain pans were a bit late.

The actual engine, note floor dry being used to soak up the coolant.

Some reflection:

Could this have been avoided? The hose was removed at the water pump with the tank more than half full of coolant, and the results are pictured.

A little poking and prodding prior to removal would have revealed a drain valve at the bottom of the tank which could have been used to drain the system with less of a mess. Though not easily accessed, a rubber hose with drain pans at the other end might have fulfilled our needs.

 Something for us to remember for next time. Lesson learned!

Cummins N-14 thermostat reinstallation

This week was shop cleanup and doing whatever was needed to get our International and FLD trucks running again.

Our International has a Cummins N-14 in it and in a previous class we had removed the thermostat housing. Unfortunately the coolant hoses running from the thermostat to the air compressor and to the water pump were so badly rotted that they crumbled into pieces when we took them off. We therefore replaced the hoses with new lines and fittings and hooked everything back up. We also hosed down and scrubbed the shop floor.

Accessability is a problem sometimes.

Thermostat housing and hoses as we reinstalled them.

Cleaning the shop floor.

Some reflection on this week:

For mechanics and technicians of both cars and trucks, accessibility can range from good to an absolute nightmare. In the case of our thermostat housing, replacing the line we broke required removal of both lines and fittings off of the air compressor. Getting to the fitting on the water pump required use of a crow's foot wrench with a ratchet and extension as there was no room to get a normal wrench on it.

Cleanup is also an important aspect of working in a shop. Not only does it look unprofessional to have an unclean shop, it also presents a safety hazard to everyone who walks through it. Oil and coolant spilled all over the floor presents a slipping hazard. Tools or parts left on the floor are a tripping hazard. So take a little extra time and keep your work area clean!

Freightliner FLD N2 injector reinstallation

This week we returned to our Freightliner FLD and began reassembly. We replaced the O-rings on all the injectors we removed (3 per injector) before returning them to their bores. We cleaned out all bolt holes of oil to ensure we would not damage the engine when we torqued the bolts down. Then we reinstalled the rocker arm assemblies and the Jake brakes and torqued them down. We did not finish the full torquing procedure before the end of class, so we marked on our service information what we still had left to do.

Preparing to change O-rings on injectors. There are 3 for each injector.

Jake brakes have been reinstalled and are ready to be to be torqued.

Looking up our specs for torquing the Jake brakes.

Some thoughts on what I learned this week:

Torque, torque, torque. Especially with internal engine components, it is important to torque bolts to the values specified by the manufacturer. Whether on gasoline or diesel engines, failing to do so can lead to problems, premature failures, or damage to engine components. The torquing procedure for the Jake brakes calls for 40 ft-lbs on all bolts starting at the intake side. It then requires you to re-torque them to 100 ft-lbs on all bolts repeating the sequence.

Sometimes the torquing procedure may ask you to torque to a certain value, then back the bolt off a certain amount. You will also encounter procedures that call for torque angle (such as when torquing the head).

Properly torquing the bolts to manufacturer specification is just good practice that can save time and money avoiding possible problems and customer comebacks.

Cummins ISB 6.7 no-start

This week we worked on a Cummins ISB 6.7L engine. This is a demonstration engine on loan to us from Cummins in our school's shop and not mounted in-vehicle. The complaint is cranking but no-start.

Our first test was checking open circuit battery voltage, which measured 1.2V. As this engine had not been run in a while, we also made other checks such as making sure that it had sufficient fuel. After charging the battery we had the same starting issues.

The engine fault lamp was illuminated so our next step was to pull the fault codes. Unfortunately, our scan tool encountered technical issues so we were not able to hook it up. Instead, we referred to service information and pulled the codes by flipping the diagnostic switch and flashing the codes. Service information indicated this would either be a dash-mounted switch or in some cases pedal-operated.

On our engine, the codes are flashed first by the amber warning lamp illuminating, followed by the red stop lamp flashing. Consecutive flashes are counted, followed by a pause, and the next set of consecutive flashes are counted. This is done until the amber warning lamp illuminates again, at which point you have read the code. The same code is then repeated, before moving on to the next code. We counted the codes in this manner until the first code recorded was repeated, then we looked up fault codes in the service information.

According to service information and the fault codes we had pulled, we had several electrical circuits, including the accelerator pedal position sensor, and fuel pump pressurizing assembly (which is pulse width modulated fuel pump actuator controlled by the ECM). We also had a code for the electronic fuel injection control valve circuit.

We tested for voltage making it to the fuel pump actuator (see video below). Key-on voltage was 6.8V, which dropped to around 3.5V when hooked to the actuator connector. There was also .7V on the connector with the key off, there should be 0. We jumped the actuator and put a full 12V to it and we could still not start the engine. We also tested the accelerator pedal position sensor circuit and found it to be working as intended.

We will continue working on this problem and find the root cause of our no-start condition.

Some thoughts on what I learned this week:

Once again we are rooted in the service information, wiring diagrams, and electrical diagnostic procedures that are a standard part of servicing modern vehicles. This will only increase in the future. Whether it's a gasoline or a diesel engine, everything from the fuel pump to the injectors is electronically controlled. While we will always have wrenches and flashlights in our toolbox, some of the most important tools at our disposal are a laptop/scan tool, service information including electrical wiring diagrams, and a good functioning DVOM.

Removal of N2 single-actuated EUI (electronic unit injectors)

This week's project was to remove the fuel injectors off of our FLD Freightliner. These injectors are N2 single-actuated EUIs (electronic unit injectors), which are bulkier than the newer N3 injectors.

In order to get the valve cover off, removal of the air filter housing and the radiator inlet hose off of the top of the valve cover was necessary. Afterwards we removed the valve cover, jake brake assemblies, rocker arm assemblys, and finally the injectors themselves. We removed the front 3 injectors from cylinders 1-3 (which I unfortunately did not remember to take pictures of)

Jake brake and rocker arm assemblies.

Valves and injector on cylinder #1.

Some thoughts on what I learned this week:

Care must be taken when removing the injectors as it is possible to spill fuel in the injector bore onto the piston. This can cause hydrostatic lock (too much non-compressible liquid in the cylinder which has no way to escape as the piston moves to top dead center on the compression stroke) and cause serious damage to vital engine components such as bending the connecting rod.

To prevent this, service literature recommends draining all the fuel from the cylinder head by removing both inlet and outlet lines at their fittings at the rear of the cylinder head and blowing low-pressure compressed air through the inlet fitting until all fuel has been purged from the cylinder head.

-Erik Miehrig

DAVCO 380 Fuel Filter/Water Separator

This is my first blog entry for our ongoing projects in Diesel Fuel Systems & Hydraulics.

This week we removed, disassembled, and inspected a DAVCO 380 fuel filter/water separator from an FLD Freightliner. This particular system does not use a primary/secondary filter, but instead uses a single filter/water separator in the low pressure (suction) side of the transfer pump. Fuel in/fuel out ports are clearly marked, and the “fuel in” fitting is equipped with a spring-loaded check ball valve. It is mounted to the frame with a bracket near the driver's side firewall by two u-bolts and is easily accessible.

Some thoughts on what I learned:

One question asked during class was if this fuel filter/water separator included a heater. As per service information, I learned that these fuel filters come with an optional fuel heater, which uses engine coolant to heat the fuel and a thermal control valve to regulate fuel temperature. When equipped, the filter housing will have coolant in/coolant out ports and electrical connections. Ours did not.

Basic maintenance is straight-forward and simply involves the replacement of the filter element and old seals. A special tool is used to remove and reinstall the top vent cap (which aids in draining) and the filter cover from the housing.

Overall a good introduction to some basic components of the fuel system on a commercial diesel truck. Of course, during this project the lessons of organization, bagging and tagging components, and the use of service information is always reinforced.

I have included a few pictures below.

 

-Erik Miehrig

Filter housing and clear cover. 

 

Spring-loaded check ball valve for "fuel in."