Cleaning and storage of Iron Block water cooled boat engine

[Shannow]

Hi all,
a mate has a boat with a 351C in it, with cooling from the lake through the water jackets.

Has a bit of corrosion inside, which as an industrial chemist, he can remove with ease.

What's the best flushing and preservation regime for these types of boats for the future ?

(Summer's 4 months away)

 

[Oro_O]

I mess with diesels that stay in the water, and in a climate we don't have to worry much. But I've helped f&f with this in the past.

My friends who do lay-up with gas use this or similar. Fill the system with the seacocks closed after flushing:

https://www.westmarine.com/buy/west-marine---50-f-engine-water-system-antifreeze-gal--499848?mrkgcl=481&mrkgadid=3337277331&cm_mmc=PS-_-Google-_-GSC%3EBrand-_-499848&product_id=499848&adpos=1o1&creative=343879478143&device=c&matchtype=&network=g&gclid=CjwKCAjwsIbpBRBNEiwAZF8-z3-mbbPTdyg5NQx0KyhXbId9yvs_SITXhP6n10LsmFoplUI2V6Tj8RoCLqsQAvD_BwE

There is an alcohol-based "RV/Marine" antifreeze that can seem similar, but it is alcohol based and not pg like this. So it's important he understand that if he's new to this. Which brings up the point, he needs to think about plumbing systems too if he has a head, sink, etc.

Some people flush out the raw water passages, blow out with compressed air, then store with the seacocks open. I don't know the design of the 351 Cleveland enough to know if that's wise; but that could be explored.

 

[Donald]

Many people fill the block with the pink RV antifreeze. Better yet fill it with an antifreeze designed for storage of a marine engine.

Most engines just blow out any rust with the spring startup.

In a lake with fresh water I doubt any cooling passage will rust thru.

 

[Schmoe]

What I do and have been doing is simply removing the drain cocks from the engine, exhaust water jackets and removing the radiator hoses to drain all the water out of the engine and then park it.

 

[LouC]

If you don't want the internal cast iron cooling passages to rust during storage I'd use a PG antifreeze rated lower than the lowest temp you will encounter. I have used West Marine -100 pg marine antifreeze (that -100 is burst rating, actual freeze rating is about -50*F) or I mix up a batch of Sierra PG antifreeze 50/50 which gives me -26F*, more than good enough in my location. Mixing up the Sierra is about half the cost of the West Marine -100 pre mix.

 

[Donald]

Originally Posted by LouC
If you don't want the internal cast iron cooling passages to rust during storage I'd use a PG antifreeze rated lower than the lowest temp you will encounter. I have used West Marine -100 pg marine antifreeze (that -100 is burst rating, actual freeze rating is about -50*F) or I mix up a batch of Sierra PG antifreeze 50/50 which gives me -26F*, more than good enough in my location. Mixing up the Sierra is about half the cost of the West Marine -100 pre mix.


This the preferred way. If you use the RV pink stuff you gas just blow it out the exhaust at startup. You can use standard auto antifreeze if you collect it in the spring.

The main point is to prevent freeze damage to the block, prevent oxygen from getting to the iron. And corrosion inhibitors.