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68' chevy 427 moving to salt water

Old 06-06-2019, 08:50 AM
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Default 68' chevy 427 moving to salt water

The question:
What should I do to keep my engine from rotting out?
The boat:
1968 Arena Craft (20' glass ski boat)
1968 Mercruiser 325hp built off a Chevy 427 big block
Raw water cooling
Stern drive

Ok so I bought this boat a year ago and was told (and the evidence shows) that it has never seen saltwater. I live on a locked freshwater canal system in Florida where the boat will be used and be stored on the lift. However, I want to be able to take it out in salt water every once in a while for the day. Or course, at the end of the day it will run through at least a mile of fresh water before being stored back on the lift. My plan is to restore the boat as well as do a full rebuild on the engine. So what are my options for making this engine last as long as possible in salt water? Should I convert the cooling system to a closed loop? Does that mean buying new headers? Or would I be okay with just dipping the engine parts in an anti-corrosion coating? Or am I worrying too much and just need to maintain the anodes? I know there's a lot of information out there but I'm just not sure what my particular situations really requires. Any advise would be much appreciated. Thanks
Old 06-06-2019, 08:57 AM
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I would leave it alone. A full FWC conversion will not pay back for this usage.
Old 06-06-2019, 11:40 AM
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Driving a mile or so back to the lift in fresh water will certainly help. Once on the lift, give it a good fresh water flush with muffs. Doses of Salt Away will be even better. I've owned 4 Stern Drive boats during my life. First one did not get flushed regularly, and it lasted 4 seasons before it needed manifolds, and even an oil pan while wet slipped in salt water. The others I flushed regularly, and had no issues after 8 years on each one, (before I sold them). And that was wet slipped, without a lift. You will be fine if you flush regularly, and it is done while the engine is still warm with T-Stats still open.
Old 06-06-2019, 01:30 PM
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Salt water is not a killer for boats. Lack of maintenance is. There are literally tens of thousands of boats that spend their whole lives in salt water. Don't listen to the hype. Flush after use and rinse the salt off. Salt Away is good.
Old 06-06-2019, 03:33 PM
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Closed cooling will allow the engine to run hotter, which is good for power and longevity.
Old 06-06-2019, 03:42 PM
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Man, you've got a 51 year old engine. If you want to keep it as long as possible, I'd definitely go the fresh water cooled route. Get a full system so the only thing that gets raw water is the heat exchanger and the risers. Good luck, probably not a lot of 427's still around.
Old 06-06-2019, 09:21 PM
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it will be nice but a maintenance hog. so decide if you are willing to let it go to the elements at some point or spend lots of time and money fixing things and getting towed in.

there is a reason you dont see 50 year old boats out on the waters.
Old 06-06-2019, 10:15 PM
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Might want to check the casting numbers on that motor might be worth more to pull it out and sell it
Old 06-07-2019, 01:50 AM
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It's not the engine that run in salt that go bad. It's the ones that sit. Install a real good and easy to connect flushing port and use it religiously. Have a hose, quick connect fitting and timer so it get a real good flush on top of the fresh water run.
Old 06-07-2019, 02:56 AM
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Spray the whole motor with a good salt water spray like CRC or something and flush don't
Let salt sleep get right on it after every use.
Old 06-07-2019, 04:21 AM
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Even if it was used in fresh water you can have flaking rust inside the engine that would clog up the heat exchanger. Normally I would say to install closed cooling on any inboard used in salt, but that is for a new engine installation. You can take the thermostat housing off and inspect inside the intake manifold. If you see a fair amount of flaking rust I would not do a closed system. Light surface rust, then yes. The use you describe will not shorten life substantially. I would try to get down low in the engine compartment and coat that oil pan with Corrosion X HD to keep it from rusting out. As a habit, check all cooling hoses for water leaks or even just a drip regularly. I had a small drip off of the manifold drain which leaked right on the starter solenoid connections and that rusted them up in a ball of corrosion. Replaced the solenoid and re-terminated the wires. Now I have different style manifolds (center riser) and drain is in a different place. Coat drain threads with Merc perfect seal or Permatex Aviation.
Old 06-07-2019, 04:37 AM
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If you're interested in saving that 427 and rebuild it... Yank it, disassemble and hot tank the motor then mothball it. The cost of a crate 454 is close to what it would cost to rebuild the 427 (sometimes cheaper), why would you want to put the 427 back in?
Old 06-07-2019, 04:39 AM
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It sounds like it will not see a lot of salt,... however... yes, if you want to maximize the life of the engine then add a full FWC system. If you are doing a full year down of the engine you can certainly have the block boiled which will clean it out like new.
Yes you can add FWC to older engines, I added it to my pair of 62 year old engines.

There is nothing lacking in ‘reliability’ either
Old 06-07-2019, 04:45 AM
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Having a mile of freshwater after running in salt is a pretty dang good flush. I would not bother with closed cooling in that case.
Old 06-07-2019, 05:09 PM
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Originally Posted by diver dave View Post
I would leave it alone. A full FWC conversion will not pay back for this usage.
So are you saying that it will be fine for a long time with just freshwater flushing after every saltwater outing? Or am I just running this for a year when it will fail and then repowering with a FWC engine? I'd really love to be able to say that it has the original engine for as long as possible.
Old 06-07-2019, 06:09 PM
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Salt water is a great preservative. We had a older Owens twin screw woodie running flagship GM 283 Chevy V8s.
I pulled the intake manifolds off both engines and rebuilt the carbs etc. Both engines were surprisingly clean.​​
Old 06-07-2019, 06:45 PM
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1968 ? Does that 427 even have hardened ext valve seats ?
Old 06-07-2019, 06:51 PM
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How about you give me the 427 and I give you a new 383 with less weight, more torque, and more horsepower?

That's a '68 GM block and has the same casting numbers as many very expensive muscle cars.

There's people who would pay quite a bit for an original '68 427 BB.

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