Well, I've been playing with my Engine block, pulled the rotating assembly out and took the block to work for "De-Rusting". I used a few carbide bits to re-open coolant passages in the top deck area...they were plugged "solid" with rust. Next, I used compressed air (while wearing a resiprator!) to clean the extreeme amounts of rust from inside the block that were accumulated in the water cooling jackets while the freeze plugs were out. I then soaked the water jackets with a light acid ( a toilet bowl cleaner!) to break the rust down while plugged with temporary rubber expansion plugs, USE CAUTION IF YOU TRY THIS, THE SOLUTION IS ACID!!! WEAR YOUR PROTECTIVE EQUIPMENT!!! After three cleaning cycles while chipping, scratching and lightly tapping in the holes for the water jackets w/a screwdriver it "ate" the 1-2 inch thick rust deposits back down to the cast Iron. Finnaly the "Freeze" crack started to flow water/ acid out of the crack indicating most of the rust was removed from the lower sump of the water jacket.
Another item I "Cleaned" was my plugged Radiator. I used "Evaporust" for 3 days with moderate results while using a temporary 12VDC water recirculating pump, I tried the "Works" and it cleaned it in aprox. 1.5 hours before it removed "ALL" the rust to reveal the leaks in the core assembly. Before this radiator cleaning was performed, the works was tested on brass and copper to find little to no negative results on those types of metals. The leaks that were revealed were on the "Tubes", not the lead solder that attaches the tubes to the top/ bottom end tanks.
Next, I moved the block over to the wash rack and used water from the hose to "Flush" out the old rust and neutralized acid untill the water came out clear, remember if you are working with Machined surfaces to clean off water from machined surfaces! (they begin to rust in as little as 5 minutes!!!)
This "Works" solution was introduced to me by a Co-Worker to be used when cleaning rusted motorcyle tanks, I accquired it at Home Depot for $1.70 a Quart and used 1 gallon so far. Be sure to use it with good ventilation because it will "Foam and Smoke" while the chemical reaction occurs!!!
1942 G7117 no. U.S.A 389946 Serial no. 9NM 22 3669
1945 G527 250 Gal. Springfield Auto Works Serial no.9218
Navy Seabee CM3 NMCB "4" 1996-2001
Caterpillar Field Service/Used parts Dept/GPS Grade Control 02-Curr