Saturday, July 23, 2016

Don't get me started!

We have to replace the Engine Harness

Time to get serious about being able to reliably start the engine.
We have had experience where not being able to start a boats engine could be close to disaster, and that is to be avoided.
So the new Engine Wiring Harness is our next job and I'll tackle it before completing the Exhaust system upgrade as it's easier to get to the engine wiring with the Exhaust system riser and the heat exchanger out of the boat.
Here are some pics...
This is our Engine Control Pane. It seems that Catalina had a variety of Control Panel Styles. If I explain our engine starting sequence and how we check the 'Heart Beat' it will make it easier to understand why and what we are doing to fix the starting issue.
The sequence is to turn the engine ignition on (remember, this is a Diesel Engine, it does not have spark plugs) Then we vent the engine bay by switching the Blower on for about 30 seconds, this is more important on gas engines, but a safety process on our boat. Then after turning the blower of, we depress the Glow Plugs button for 20 seconds, this preheats the engine cylinders raising the temperature and making it easier to get the engine to the condition where the diesel fuel will combust due to the pressure in the cylinders. After releasing the Glow Plug button we depress the starter button.
Normally the engine would fire into life without the slightest hesitation. However, the past two times it has been reluctant to start.

The issue appears to be due to excessive resistance in the wiring harness that is causing the starter to hesitate. 

Here's what the wiring behind the Control Panel looks like.
This is Ugly!
Several things jump out here.
The wires are really poorly crimped, not insulated nor labled.
Some o the instruments show signs of overheating.
The wires are not appropriately sized, and skinny wires can over heat, thus causing a variety of issues, not the least is FIRE.
The panel has been repaired and not very well. There are alarm buzzers that have probably failed and replaced by ones that are secured to the existing wires rather than mounting them securely on the panel. 
The list goes. on.

Down in the Engine Bay, it does not get any better.
Existing Euro style terminal block in the engine bay
Some of the cable are showing signs of overheating, corrosion and insecurity in the terminal block. Plus the block is not particularly appropriate in a boat with a diesel engine. Vibration is normal, and corrosion of the cable ends and terminals is hastened due to a lack of water tight connections.

So it's all coming out!
The new harness will be enclosed in an expansive sleeve to resist chaffing, all new wires and new terminals. No terminal block at either the Control Panel or at the Engine. The wires will go directly from the Control Panel to their respective engine service/sensor.

All of that training that the Royal Navy gave me in maintaining helicopter electronics is paying off (again)

The materials for the new harness have started to come in, many of them ordered from Ken of Weekendr . I have the Sleeve and heat shrink tubing, my wiring labeling process is top notch thanks to the advice given by Mainesail on his website.

The Heart Beat

While under motor, there's plenty to keep our attention and it's easy to forget the engine that is working hard at moving us along on the water. As Peggy was a Nurse for 40 years, I suggested that we think about the Engine's Heart Beat and check it about every 10 minutes. If I'm up on the front of the boat or down below, I'll prompt Peggy to check the heart beat by giving her the Two fingers on my wrist signal.

When we check the heart beat, we simply look over the stern and make sure the engine is coughing out water with the exhaust gasses, then a quick glance at the Instruments, Left to Right: RPM, Temperature, Fuel and Voltage. If it's ok, then we just acknowledge with the thumbs up signal. If not, we'll spring into action and consider shutting the engine down really quickly. That may mean that we'll have to drop anchor if the location allows, or tie up along side or just drift. Of course, there's always the option to pull the sails out.

The Harness Upgrade.

Step 1. Research! find wiring diagrams that are a close match to our boat and from that make a detailed diagram that reflects the actual wiring on Eximius.

Step 2. Figure out what we need, what wires, terminals, blocks, heat shrink tubing, sleeving, labeling and tie wraps to secure the new harness in place in order to minimize chafing an strain on the connections.

Step 3. Remove the Control panel and figure out what bits need replacement, repair and how to rewire it.

Step 4. Make up the new harness and connect it to the Control Panel

Step 5. Install the new harness and make up all of the terminal connections to the engine services and sensors.

Step 6. Cut out the old harness - being careful to not cut out anything that has nothing to do with the engine controls (such as Auto Pilot, Navigation electronics etc.)

Step 7. Test it.

Now to get started. I'll go down to the boat and remove the Engine Control Panel and bring it home so that I can get Step 3. done in the comfort of my garage.

Stay tuned.

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