Monday, January 13, 2014

Servicing Diesel Engines

As I mentioned in a previous post, I'm having some work done on the engines.  Specifically I am having an injector pump replaced and I'm having the heat exchangers cleaned.  It was also recommended that I perform a basic service on all the engines so I had a known baseline where I can start tracking regular maintenance.  Now I'm fairly handy and know my way around automotive gasoline engines, a diesel on a boat is a new thing for me and I don't want to screw something up. So, while the coolers and injector pump are off getting worked on, I had a guy at the local marina (who has lived onboard for over 15 years and regularly does maintenance for people at the marina) come help me with the service.

Typically, this maintenance includes changing the oil and filter, changing the fuel filters, checking the raw water strainer, changing the impeller, checking or changing the engine zincs, and adjusting or replacing the fan belts.  My Leopard 38 is powered by two Westerbeke 42 B Four engines and I also have a Northern Lights Generator (Lugger Engine) that will need service.  Yep, Not one, not two, but three diesel engines that need service.  This is one of the downsides of a catamaran, they have at least twice the number of engines to service than the typical mono-hull.

Sourcing Parts

When I bought the boat, it came with a number of spare parts including zincs, impellers, oil and fuel filters. The two items I knew I would need and did not have were fan belts and oil.

For the fan belts, you can't exactly walk into your local Advance or Auto Zone and ask for one.  It usually falls apart right about the time they ask you what make of car it is for. "It is actually for a boat"...employee just stares blankly at you. I had found some specifications on the internet for the size of the belt and tried to get one based on that.  Naturally, that resulted in a belt that was too small.  I finally broke down and took one of the belts in and they were able to figure out the size (the part number is 15420 - the 420 is the important part as that is the size so the 15 in the Auto Zone number could be something else at another store).  The next problem is that each engine takes two belts.  As it turns out there was a total of one belt of that size in the three nearby auto parts stores.  I'm glad the belts on the engines are in good shape as that only leaves me with a single spare for the engines.  I haven't even looked for the belt for the generator yet.

For the oil, a few people suggested using Rotella.  So off to the store I go looking for it.  Well, as it turns out, Rotella is the "model" name for Shell's diesel engine oil and there are several variants (T, T1, T5, and T6) that range from a standard single weight mineral oil to a multi-viscosity full synthetic. Since I could only find the 10w30 that was mentioned in the Westerbeke manual in the semi-synthetic, that was the one I picked up.  3 gallons of the stuff was pretty expensive.  Of course, when I showed that to the guy that was helping me, he highly suggested using the standard Rotella T oil and that he's been running 15w40 in his Westerbeke engine for a long time and it will be what I will most likely find when I'm in the islands.  So, the good news is I can use cheaper oil, the bad news is I had to go back to the store to switch it.

Northern Lights Generator

We start with the generator as it is the easiest to access, just under the transom hatch.  The engine has a hose at the bottom of the oil pan to help drain the oil, but I don't have a fitting for it, so we decide to use an oil changing pump that came with the boat to extract the oil through the dipstick opening.  It was a somewhat slow process, but we did get the oil extracted without a mess.  The oil filter change is just like a car...with the usual mess from the fact it is mounted sideways and holds oil.  The oil absorbent pads (they absorb oils and fuels but not water) are a definite necessity for this task.

The fuel filter for this motor is a canister type that looks just like an oil filter and is replaced in about the same manner (including the oil absorbent pad to catch the spilled diesel).  I guess I should also mention that we shut off the fuel supply lines since I didn't want any more diesel filling up the engine room bilges.

Since the heat exchangers are off being serviced, I assume new zincs will come back with them so we don't have to worry about that at this time.  (Note: later I spoke with the guy working on the heat exchangers and he indicated that, due to the design, the zincs are not mounted there.  Guess we will have to go back and look at the generator engine again to see where the elusive zinc is located.) The fan belt seems to be in good shape, so we just check the tension on it and move on.

Removal of the impeller was interesting.  While it slips on and off the shaft reasonably easy, there is a pretty tight tolerance between the shaft and the collar on the impeller so it has to be removed without twisting it on the shaft or it will just jam.  Two flat screwdrivers at opposite sides of the impeller seem to do the trick...eventually.  Installing the impeller is pretty straight forward, but there is one trick I hadn't thought of.  Since the impeller will be dry, they usually come with some lubricant that helps to install them as well as keep them wet until the cooling water makes it to the point where it can prevent excessive friction.  Without this, the dry rubber impeller rubbing against the metal housing would likely destroy the new impeller before the water can get there and keep things lubricated.  Installation is pretty straight forward, you figure out which way it spins and twist it in that direction as you push it into place making sure that the pin lines up with the slot in the shaft.

Westerbeke Engines

The Westerbeke engines are a bit more complicated.  They are larger and take up much of the space in the narrow hulls of a catamaran, which makes it fun to work on.  On the starboard side we have a engine room with enough space to stand up.  The port side is under the berth, so it is a bit more cramped but there is access both via the transom and from a hatch under the bunk.

This time we start by draining the oil since it takes a while to drain cold, thick oil.  While it is draining, we replace the fuel filters...plural.  Yes, each engine has two fuel filters.  There is a primary Racor filter that is mounted on a bulkhead and a secondary small cartridge filter mounted on the engine itself.  The small secondary filter is a 10 micron cartridge and for the primary I have a choice of 30 micron, 10 micron, or 2 micron filters.  We decide to install the 2 micron filters as that will effectively keep the smaller one clean and the larger Racor is much easier to replace if we ever had a clogged filter occur during operation.

We replace the oil filter and again check the tension and condition of the belts.  Just as the case with the generator, the heat exchangers are not installed there is no way to check or replace the zincs at this time.

The impellers ended up being an interesting puzzle.  As with much of this service, I have been using the spares that were left behind by the previous owner and then would go out and get new spares.  We get the old impeller out of the starboard engine without problem, but the replacement impeller just woldn't seem to go in.  After much struggling, we ended up removing the pump so we could better see why the impeller wouldn't fit.  We come to find that, while the spares (different than the ones for the generator) look virtually identical to the impeller we removed, the center shaft of the spare was thicker and could not be pushed into the slot on the shaft.  Fortunately, the old impeller's pin was threaded and could be removed and one of the spares also had a thread so we swapped out the pin and viola, it now fit just fine.  Unfortunately the other two impellers I had on hand had pins that were press fit, so I couldn't repeat this trick for the other engine.  Will need to go find another impeller that will fit.  So, if you have a Westerbeke...or ever get particular attention to the impeller...apparently only the genuine Westerbeke ones fit the Westerbeke pump.

At this point, I am waiting for the parts to come back so we can finish assembling the engines, add the oil, bleed the fuel system, and get everything running again. It will be nice to see the engines running again...hopefully without the fuel leak or temperature issue.  And this definitely was a learning experience.

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