Cleaning a bare block: acid in cylinders?

[scratchee]

I have my block stripped bare and am trying to figure the best way to clean it, worst need being the cooling passages. If I use some sort of acid bath, could it damage the cylinder walls? I have no need to do anything with the cylinders, but since everything is stripped off the block I can't exactly "flush" the passages alone since there are openings everywhere.

Is there a standard approach at this stage? Thanks for any advice!

[Marian Claire]

IIRC. I used a pressure washer after a lot of poking and brushing of the water passages. Had to quickly oil everything to stop flash rusting.

Dan
S/V Marian Claire

[Al Schober]

When you clean the passages, pay attention to the small ones in the top of the block. These tend to scale up with raw water cooled engines. A drill bit or a diamond burr in a Dremel tool are good weapons. The passages near the valves don't go straight but have a dogleg in them. Save the acid flush for after things are back together.
This is also a good time to install studs for the cover plate into the water jacket. The original bolts are a known source of leaks.

[ronstory]

A sturdy coat hanger and lot of poking in the corners works well for round the cylinder and passages. I also use these mounted int a drill to get into nooks and crannies.

https://www.amazon.com/HTS-101G5-Bristle-Tobacco-Cleaning/dp/B01MXMACSR/ref=sr_1_7?dchild=1&keywords=metal+pipe+brush&qid=1616006627&sr=8-7

A regular screwdriver can be good for the edges of the passageways.

Also, the most scale I got out of the head was when I replaced the core/freeze plugs. This was after using all the above tools. I was simply astounded as how much extra scale came out after driving in the new plugs.

[scratchee]

Thanks everyone. I'll hold off on the acid for now.