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.