Time has flown by since our last blog around Christmas but of course, work never stops on our Vanish. We haven't had a "Tech Corner" for a while so we thought it might be about time. We have been doing some serious maintenance and minor refits onboard Vanish over the winter season in Freeport, Bahamas. The main piece of major maintenance that we completed was our 1,000 hour service on the main engines. What follows is a brief synopsis of the service and what we learned.
The Caterpillar C18 1000 hour service consists of 5 key tasks:
- Inspect the heat exchangers and change coolant
- Clean and Test the after cooler cores
- Inspect housings and replace sea water impellers
- Inspect the Turbochargers
- Replace the Closed Crankcase Ventilation Filter
We also decided to change the oil on both engines, both generators, and both transmissions while we were at it. We hired an engineer from Bradford Marine in Freeport named Dinyar to help Mike and answer any questions we might have along the way. It was also easiest to get the filters, oil, and coolant through Bradford Marine. We have a Reverso oil change pump that allows us to drain and fill the engines and generators from a quick connect on the swim platform. This makes things a lot easier so we don't have to carry oil cans all over the boat. We are always sure to take an oil sample and send it in to the Caterpillar Research Center in Peoria, Illinois, USA. After draining the oil we replaced all of the Racor filters (2 for each engine and each generator, a total of 8) as well as one fuel and one oil filter on each unit. After refilling the oil we brought the engines and generators up to temperature individually and made sure the oil was at the correct level on the dipstick and all temperatures and pressures were normal.
The ZF transmission oil was extremely clean already but we decided to keep up with manufacturer recommendations and change that. The only difference was that this oil had to be filled with a funnel directly on the unit's fill cap. Next, we drained the coolant from the main engines. It was somewhat difficult to find the lowest point to extract the coolant and the starboard engine had a drain plug slightly lower than the port engine so we got an extra gallon or so out of that engine. Dinyar made it clear that this wasn't a big issue to worry about as the goal was to get the majority out of it. We removed overflow containers and scrubbed them since they had a little sludge residue in them. We refilled the coolant through the fill cap on the top of the coolant reservoir and then filled the overflow containers to the cold line. Again we brought the engines up to temperature and made sure levels and pressures were normal.
Taking off the aftercooler cores would be the biggest task of the whole service because the housings are 2 feet by 3 feet of solid steel. Thankfully the engine room is big enough to allow two people to lift them off. We can't imagine what it would have been like if it were any smaller. There are 34 bolts that need to be removed as well as disconnecting the inlet and outlets. The entire unit is 75 pounds so we had to be very careful to not let it fall, and it is important to remember to close the sea-cock before removal. The next step was to remove the aftercooler core from the housing for cleaning and examination. To clean the core we filled it completely with diluted barnacle buster to remove any growth or scale. After letting it sit for 2 hours we emptied the barnacle buster into a 5 gallon bucket and rinsed it with fresh water. Then we sprayed both sides with fresh water on low pressure, and dried the core using a shop-vac and an air pump we use to fill the fenders. It is important to make sure that there is free air flow through the core and the easiest way to test was to put the air pump on "inflate" and see if you can feel the air blowing through the other side of the core.
We greased the inlet/outlets with a high-temp grease and reinstalled the core into the housing. It was very difficult to reinstall the core onto the engine without ruining the new gasket. With two people, one could guide the core and make sure the gasket wasn't crushed while the other did the heavy lifting.
While we had the sea-cock still closed we figured it was best to inspect and change the sea water impellers. We were very happy to see that both impellers were in great condition and weren't missing a single fin. It is important to inspect the impeller housings for irregular wear or damage, feel the inside with your bare fingers for any grooves or abrasions. The impellers have a thread on the outer end so they are easy to remove with the provided bolt and a socket wrench. Dinyar taught us that when installing a water impeller you should use grease that is dissolvable in water. Silicone based grease resists water and can cause the impeller fins to stick. We used dish soap (Joy to be precise).
Our Cat-18 engines are twin turbocharged, so we had four total turbos to inspect. To inspect the turbo you simply remove the air filter to expose the turbo fan. Grab the center of the fan and spin it, listen for any scraping of the fan against the housing and watch for any irregular motion or wobbling. Then wiggle the turbo fan back and forth and up and down to see if it is loose at all. The fan should spin perfectly and not hit any of the sides. Visually examine for any corrosion or foreign objects. K&N makes a good filter cleaning and oil kit and we are sure to clean and oil the filters whenever we remove them.
Replacing the Closed Crankcase Ventilation filter is simple. All you have to do is remove the clips on the plastic housing, being careful due to there usually being a small amount of oil in the bottom, and take out the old filter and put in a new one. Our engine service went very smoothly and thankfully we didn't have to replace any major parts or have any continued maintenance out of the ordinary. We have been using a fuel additive called Enerburn which is a newer product being used in many types of diesel engines all across the world. Enerburn is a catalyst that is designed to help diesel fuel burn cleaner, reduce engine wear, increase gas mileage, and generally help the engine perform better over a long period of time. You can take a look at the benefits of Enerburn on their website www.enerburn.com. We were very eager to see the results of the oil sample to see if the Enerburn was worth adding.
It turns out our oil sample came back with very good results and the soot and carbon levels were very low even though we did nearly 400 hours since the last service. This is a testament to the Enerburn as well as the ability of the CAT engines themselves to perform at such a high level. We will continue to monitor the engines' performance through these oil samples as often as possible. We are continuing with other maintenance on Vanish before we head off again in the next month or so.