# Protect cast iron cylinder against rust



## xander janssen (Sep 18, 2020)

Hi,

After building a Jan Ridders engine, I'm planning to design my first engine from scratch. I'm quite confident that I can finish the mechanical design. However I lack some specific information which I hope to find in this forum.

My plan is to have the cooling water (with additives) to flow around the cylinder lining directly. Is there any special need to protect the cast iron from rust?  If so, what do you use? I can imagine some zinc-spray or exhaust-paint could help shielding the CI from the water. 

Is it better to keep the water in the engine between sporadical runs or to fully drain the engine each time?

Regards,

Xander


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## Asm109 (Sep 18, 2020)

Cast iron car engines keep coolant in them 24/7 for years without major rust problem, so no coatings are required. That said, I would drain and dry out my engine if it is going to spend most of its time sitting.


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## stevehuckss396 (Sep 18, 2020)

Use waterwetter mixed with water. It has all the antitrust agents and lube that coolant has without the glycol.  Cools better than coolant. Available at most auto parts stores.


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