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Freedom Chip Counter
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Discussion Starter #1
Another NOOB question...

Curiously my little Atomic 4 seems to have been quite happy pumping raw sea water through the cooling system for the past 46 years, but I've heard of many people converting the cooling over to a fresh water system.

What keeps the pour thing from rusting inside / out? I'm thinking the block is steel....are there aluminum sleeves or raceways? Stainless inserts....or is it just a matter of time before she rusts all the way through?
 

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Barquito
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I understand that internal rusting is often the demise of this tough engine. Seems like 46 years and counting is not too bad for any engine.
 

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The block is cast iron - not steel, and it does rust, but much slower than steel for some reason. Now, there are two steel plates on the side of the engine, which do rust through. I had that happen to one that I had in a 27 Catalina. I was able to obtain a replacement plate from Moyer Marine in Rock Hall, Maryland and installation only took about 30 minutes.

All the best,

Gary :cool:
 

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Old enough to know better
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4,342 Posts
Yes the only thing that seems to kill these motors is rust. Obviously it takes a long time, that is why I don't see putting in a fresh water cooling system is really all that necessary. it adds a lot of complications. I think I might not even do it if I bought a new block, after all if it lasted 46 years, I won't be sailing that long. It would push the price of putting in a new engine to the territory of putting in a diesel. Kind of like the electronic ignition kit, sure it gives a hotter spark but the points and condenser works quite well, and you can carry several spares. I think I have every one the previous owner has ever replaced on mine. I think I have at least 8 sets.

A few advantages is that the motor can run hotter, as they like to do. You can also get more heat out of the motor to a hot water tank and a bus heater to heat the interior.
 

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The one I now have on my Morgan 33 OI is freshwater cooled, and the heat exchanger routes through my hotwater tank, which is about 15 gallons, and very well insulated. I only use about two gallons for a shower, and less for washing and rinsing the dishes. This engine is a reubuild from Moyer and installed in 2001. It runs like a Swiss watch, but has some blowby that I have to take care of this winter. I think the crankcase vent is plugged. Not a big deal to fix.

All the best,

Gary :cool:
 

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Tartan 27' owner
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5,242 Posts
Yes, the old rusty Atomic bomb. Mine is 48 years old. RWC.

Part of my winterizing procedure for my engine is to run a gallon of white vinegar then at least 10 gallons of fresh water through it before running a gallon or two of antifreeze. Antifreeze has some anti-rust qualities to it.

On the other hand, there is no reason not to add a FWC system to your engine if you really love it. Both Moyer and Indigo sell FWC upgade kits.

http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=CFWK&keywords=all&template=Templates/B000_storebuilder.html

http://www.atomic4.com/freshwater.html
 

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The block and exhaust manifold of the A4 are cast iron.
When continually and repetitively heated above 150°F the internal 'rust' will become a blue/black form of rust (ferrous oxide) which is 'protective'. With long periods of lay-up, this ferrous rust will convert back to destructive red (ferric) rust.

Rx to keep the rust 'black':
1. run hell of the engine, keep the water temp at a bit over 150° (regularly check that raw water thermostat for proper operating temperature).
2. Never, never, never, ever drain the water from the engine for long term 'lay-up'; always fill up the cooling system with 50:50 antifreeze mixture with added 'anti-rust' compounds. The oxygen laden moisture remaining in a 'drained' cast iron engine will greatly accelerate the 'black' rust rapidly converting into destructive 'red' rust.
3. Never, never, never, ever 'pickle' such an engine or exhaust manifold with muriatic or hydrochloric acid (or 'vinegar', etc.) to remove the usual internal calcium carbonate scale buildup/fouling. ONLY 'descale' the engine with an INHIBITED descaling chemical such as RydLyme, etc. Then run the hell out of it to restore that protective ferrous black rust.
4. Convert the engine to 'fresh water cooling' (heat exchanger).

Good source of info for maintenance, repair, rebuilding, parts, 'modernizing', etc.: Moyer Marine Atomic 4 Engine Rebuilding and Parts
 

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Freedom Chip Counter
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259 Posts
Discussion Starter #8
The block and exhaust manifold of the A4 are cast iron.
When continually and repetitively heated above 150°F the internal 'rust' will become a blue/black form of rust (ferrous oxide) which is 'protective'. With long periods of lay-up, this ferrous rust will convert back to destructive red (ferric) rust.

Rx to keep the rust 'black':
1. run hell of the engine, keep the water temp at a bit over 150° (regularly check that raw water thermostat for proper operating temperature).
2. Never, never, never, ever drain the water from the engine for long term 'lay-up'; always fill up the cooling system with 50:50 antifreeze mixture with added 'anti-rust' compounds. The moisture remaining in a 'drained' cast iron engine will greatly accelerate the 'black' rust rapidly converting into destructive 'red' rust.
3. Never, never, never, ever 'pickle' such an engine or exhaust manifold with muriatic or hydrochloric acid (or 'vinegar', etc.) to remove the usual internal calcium carbonate scale buildup/fouling. ONLY 'descale' the engine with an INHIBITED descaling chemical such as RydLyme, etc. Then run the hell out of it to restore that protective ferrous black rust.
4. Convert the engine to 'fresh water cooling' (heat exchanger).

Good source of info for maintenance, repair, rebuilding, parts, 'modernizing', etc.: Moyer Marine Atomic 4 Engine Rebuilding and Parts
Thanks!

I've been running her dry the last few nights thinking it was better not to have sea water left in the system....something inside was telling me this was probably NOT a good thing to do....You confirmed this! Awesome!
 

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Convert to freshwater-the blocks are a molybednum alloy and relatively impervious to rust, but 46 years is pushing it. Once you convert you"ll wonder why you waited so long-plus winterizing is a snap. Dealing with points and condensers is archaic-tune ups are a matter of replacing plugs every few years once you change to an electronic ignition-and its simple to install and stays on spec forever....
 
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