Week 3

On Monday when I came to class I went to check out the 6.0 Ford project and Dan had his class come over to show them some stuff. One of the things Dan was talking about was cavitation and why in diesels it is so important to have the correct coolant. I learned that its caused by little air bubbles in the coolant forming up against stuff like cylinder liners and when ignition occurs there is so much pressure that the liners want to expand and it causes the air bubbles to pop. From continuous popping of the air bubbles it will wear away at the liners causing holes in them.

On Wednesday day I started my internship at the Stanwood bus garage. I started out changing a wiper arm and bracket on a bus and doing some general maintenance like changing fuel filters and air filters. Then I got to learn how to write a service report to keep track of all the work you do and which parts you used so you can keep track of them for inventory.

Thursday I got to learn how to adjust valves on a cat c7 in one of the buses. The engine was set on top dead center by removing an access bolt in the back of the engine and then inserting a wood dowel rod against the flywheel and turning the engine over by hand until the dowel rod slides into a hole on the flywheel. After we got the engine on top dead center Scott showed me how to adjust the valves and then set me loose to do the rest and to have one of the other techs check out my work when I was done. After I got half the intake and exhaust valves set I had one of the techs check them and he said they were a little loose and he showed me some tricks. So I reset those valves and had him check them again and he said they were good. Then I had to rotate the engine 360 degrees to do the other three intake and exhaust valves. I got those valves set and had the tech check them and they were good.

 

The number 6 cylinder was kind of a pain to do because of the limited amount of space you have to work with

 

The white mark is aligned with the serpentine belt to show where top dead center is for when you rotate the engine to complete the valve adjustments

 

On Friday I got to drive the bus garages service truck for a bit because a bus had to be taken to the cat dealer for warranty work because it wouldn't go into regen to clean out the diesel particle filter. Then I got to learn from one of the techs about removing and installing injector cups on a cat motor with a heui injection system while he was working on it. Its important to clean out any oil, fuel, and coolant that goes into the cylinder after the cups are removed to prevent the engine from hydro locking once its back together. Then I got to end the day with adjusting some more valves on another cat motor. This motor had a high pressure fuel system on it so you don't want to mess with any of the fuel lines because the fuel is under such high amount pressure that it can cause really serious injuries.

I got to replace this bolt will we were inspecting this bus and the other tech told me that if you find something broken you get to be the one to replace it. On this bus a driver reported hearing a clunking sound and then smell somethings hot which ended up being this lower shock mounting bolt breaking and this is a grade 8 bolt. Initially we had checked it for blown boost couples and checked the cooling system. This was found after the bus got put up on a lift to check the underside

 

week 3 = 32 hours,  total = 46 hours