Here is another question related to my previous thread requesting recommendations for Machine Shops in MI. Apparently very few shops still have Hot Tanks for cleaning bocks and heads thoroughly prior to machining. For my open cooling system engines there is a LOT of scale in the water jackets and I felt it would be beneficial to have the blocks hot tanked as part of the rebuild process. I don't see where the "Bake and Blast" process will really clean the cooling passages. What is the current consensus on the need for hot tanking a open cooling system marine block as part of the rebuild process?

The last engines I built were over 25 years ago and almost every shop had a Hot Tank. Apparently the EPA has made the use of the caustic cleaner in hot tanks more difficult for machine shops to use.

Thanks.

I've been having them baked and blasted for about 20yrs. I'm talking probably 1000 blocks give or take a few. I've yet to see one not come out looking like a fresh cast block. Plus the hot tank isn't what it used to be. The chemicals of yesteryear were 100 times better than what they can use now.

I used electrolysis to clean the inside of the block before it went to the machinist. I got a plastic 55 gallon drum off of craigslist.org and let it soak for 36 hours , it broke up tons of scale in the cooling system.