Counter-Act (on right in picture) is the only active proven product that I could find that is made to stop corrosion, which is the true marine diesel killer. I think Peter Compton said it best in his book Troubleshooting Marine Diesels:
"Corrosion is the natural deterioration of metals, due mostly to their surface reaction with oxygen. This reaction usually is chemical or electrochemical and is accelerated by the presence of water and heat. Electrochemical or electrolytic corrosion occurs through a reaction between dissimilar metals in the presence of water or chemicals that form an electrolyte. Considering the combination of hot metal, hot exhaust gases, and seawater to which they're exposed, it's not surprising that most engines head for the diesel graveyard long before they wear out. Corrosion is the marine diesel's number one enemy. During the life of the average diesel, owners will spend more money on corrosion induced failures than any other cause."
You would think with a statement like this all hope would be lost in preventing corrosion. Yet in his book he goes on to say in the following paragraphs that regular maintenance and care should prevent most corrosion. I completely disagree. There is no way regular maintenance can possibly keep the engine from disintegrating. I have tried in vain, paying professional mechanics for expensive maintenance has not slowed the rusting. Replacing the zinc in the engine seems to be a never ending job, since they don't even last a month. The number of dissimilar metals used for the engine and out-drive guarantees that the engine will eat itself up unless drastic measures are taken. Frankly after only 4 years of light use the engine did not look as if it would last another 4. I searched for several days for a solution on the Internet and discovered CounterAct.
Everything you need included:
Here is the CounterAct system designed for large SUVS with 4 charged couplers. The system I actually installed on the Westerbeke engine is the much cheaper version designed for cars and vans (Model PA-1 $299) which only has one charged coupler. I bought this more expensive version for my truck after I saw the great results on the engine. In the picture (left, click on picture to enlarge) you see on the right bottom the CounterAct unit, charged couplers in the middle, wire at the top right and plastic bag containing electrical connectors in-line fuse and ring connectors for the battery connections. Basically everything you need including the alcohol pads required to clean the surface to mount the unit and the couplers with the double sided adhesive tape is included.
In general the most difficult issue in the installation was finding a suitable location for the coupler since it requires a location that is flat and that does not get too hot. The only location I could find is on the steel mounting plate for the solenoid (see picture left, it is white square behind the hoses above the selonoid). The control unit I mounted inside the port locker next to the engine (see picture top of page) and connected the three wires, positive with in-line fuse to battery, negative to engine ground and third wire to the coupler. The instruction provided were fairly basic text (no pictures) but were sufficient to install the unit since it is so simple.
How it works:
This CounterAct unit produces a high voltage charge pulse about twice a second of a minimum of 350 volts using extremely low amperage to charge the coupler which is not in physical contact with the engine and acts as a dielectric plate (it is encapsulated in epoxy and plastic). This has the effect of causing the entire engine to become negatively charged plate which nullifies all differences in potential and thus stops the corrosion. The unit detects the engine charge and adjusts as necessary to maintain an even potential for the engine. It even has a low voltage sensor to determine if the battery voltage drops too low to shut itself down before the battery reaches a level that it could not start the engine. The flashing LED on the unit indicates when it activates to charge the coupler. It also makes a barely audible high pitch sound with each pulse that thankfully can only be heard with the lockers cover open.
For more details on the way it works, I suggest you check out the manufacturers website: http://www.counteractrust.com/.
I am sure you are wondering "does it work?" Well, the engine zinc in the heat exchanger after 6 months (pictured) still looked good. Before installing CounterAct, this zinc would be completely dissolved in a month and thus needed to be changed every three weeks to provide any protection!!! There is no question that it is making a significant difference. Bye bye corrosion problems....Thank You CounterAct. I just wish I had installed it when I first bought the boat.