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FWC kit for Atomic 4, a good idea?

8K views 20 replies 11 participants last post by  FirstCandC 
#1 ·
Hoping for some more good advice: My '79 A-4 runs well but the temp is quite variable. Reading about the Indigo FWC kit and their new t-stat sounds like cat's meow - but is it foolish to go at fixing things that are not real broken (yet). Last summer was my first with this boat/engine, so I don't have much history at all.
Thanks for your ideas.
 
#4 ·
How old is the A 4, find someone who can tell you how much of the engine block is still left salt water carrodes from the inside out. An A 4 will run almost forever (good engine), FWC is a life saver for the A 4. Runs better and lasts longer. Check out the engine. If it is still good, go for it.
 
#5 ·
Thanks Desert Rat. The engine is a '79, with a "rebuild" 10 or so years ago. Not clear what all was actually rebuilt but there is electric fuel pump, electronic ignition, etc. So far there seems strong support for going FWC. It does run well. Lots of crud came out with vinegar wash at haul out.
 
#6 ·
Actually I personally I have only worked on the mechanical units and in my opinion the Moyer would be better IMO others may chime in that have experience with the electric units ( with fwc there are several side bennifits like a heat exchanger for domestic hot water also you can run a heater just like in a car( red dot ) for extended season sailing
 
#8 ·
DR has nailed the conundrum with questions like this. FWC is better on many fronts, but converting a badly corroded block may not make sense.

The difficulty is in accurately assessing the block to make that call.

EDIT.. it's good and helpful to know where you're sailing.. maybe fill out more detail in your profile?
 
#10 · (Edited)
I've always understood that RWC engines used in a salt water environment should never be converted to FWC. The salt is so embedded into the internal passages that it will never come out and then when converted to FWC and anti freeze is put into the cooling system, the salt will have a negative reaction with the antifreeze and clog the passages.

My suggestion, find a way that you can easily and frequently flush your engine.
I have a FWC diesel that I flush just about every time I use it. Of course, I'm only flushing the raw water side, but I figure it will buy me extra years before replacing my riser or heat exchanger. Takes me less than 5 minutes to flush my engine.
 
#11 ·
I have a friend that did the conversion many years ago (he has since sold the boat). He did have to do an acid flush (using Rydlyme) of the cooling passages to remove any scale. The system worked well for many years. Pretty sure he used the Moyer system. I would do it if you intend to keep the boat.
 
#12 ·
Chuck, that's an old wives tale that never really had any substance to it at all. In reality, the only thing that remains inside the engine is the corrosion - not the salt. Now, the FWC system will provide you with lots of corrosion protection from that point forward. Be sure to use a good grade of antifreeze, check it frequently, and if the temperature is variable, the culprit is usually the thermostat.

My A4 has thousands upon thousands of hours on it, runs like a Swiss watch, and I would not even think of converting to diesel. If and when the engine dies, I would replace it with an A4 gasoline substitute, though they cost a bit more than a diesel replacement of the same HP.

Good luck,

Gary :cool:
 
#13 ·
When I re powered with an exchange from Moyer 5 years ago I included the fw cooling option from Indeglo. I am glad I have it. Installation took some "cleverness". I run a little cool here along the Maine coast. I added a rw pickup strainer that lives in the bilge. I can switch the rw pick up to it and fill the heat exchanger and wl muffler with antifreeze easily. It would allow the rw pump to serve as an engine driven aux. bilge pump if necessary. The engine is always "winterized".

Down
 
#16 ·
The old wifes tail is called salt creep :) and while not much is said now in the past it was not recommended due to the scale chunks clogging the exchanger and it does due some wired stuff turning everything inside black

I due OWN two A4 blocks one always salt and the one 1970 block i rebuilt 5 years ago that was made FWC in 1980 by my PO



The saltwater block was carboned up like crazy due to the low water temp saltwater requires YET most things like head studs came off easy as i removed donor parts



On the other hand NONE of the studs were coming out of the block that had run FWC going back to 1980

Again due to lack of thermostat maintenance the motor was run way to cool and carbon forms under the valves in the air intake passages to the point of barley ABLE TO RUN



after much cleaning and gasket and seals



It has ticked away for 5 more while being run as long as 12 hours at a time when the LIS plays dead sea years and is celebrating its 45th Birthday

IMHP the indigo stuff is needlessly complex adding stuff that is just not necessary as it runs very happy with nothing more than the exchanger and second water-pump

 
#17 ·
If you want to keep that A4 carbon free and keep those valves well seated, there's nothing on the planet better than Marvel Mystery Oil. Even Moyer highly recommends using this stuff, and in my old C-27, that engine would not start unless I kept the fuel and oil treated with Marvel Mystery Oil. This is the one product that I can truthfully say works very well in keeping those old A4s happy.

Good Luck,

Gary :cool:
 
#19 ·
That is what Gary seems to keep saying about the stuff. Won't hurt the fuel system. As much as he talks about it makes me wonder if he's the inventor ( he is old enough to be). :laugher:laugher:laugher:laugher. Seriously though marvel is good stuff
 
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