Engine block coolant cavity vinegar soak

[George Hand]

After giving my bare1920 engine block coolant cavity a vinegar soak for a week & wash I took it to have it bored for new .030 over aluminum pistons. I set the 1925 block on the bench for it's turn with the vinegar treatment, chunks of crud started to float to the top within a few minutes. As with the last block the soft (core) plugs started to weep vinegar. There is not as much erosion around the water ports as the 1920 block has, but the deck is pitted some from what appears to have been a bad Headgasket & I may have to have a couple valve seats replaced. I have the seats & the man in his 80's doing the work is more than capable of those repairs also. As with the 1920 block i will need to assemble the crank, a rod with bare aluminum piston to gage the upper piston ring land exposure prior to any deck machining. George

[jiminbartow]

While soaking steel parts in acid to remove rust, is acceptable, one has to be very careful about using any kind of acid (no matter how weak), on cast iron, such as the engine block, because cast iron is so porous. The acid will get inside the pores and eat the cast iron from the inside out. If you start with a smooth piece of cast iron, after a short exposure to acid, the once smooth cast iron will resemble a piece of pumice. Just be careful. Jim Patrick

[Adam]

Yes, EVERYONE who does any kind of vinegar or acid soak with their cooling system or block might be asking for trouble. Not right away, but maybe 20 years down the road...

It’s like bleaching an original revolutionary war flag to get clean it up....

[George Hand]

Hello all, I doubt soaking my engine blocks will create a problem, I explored having the blocks oven baked but felt that it may make more problems with cracking which is what modern engine builders do with newer engine blocks. When I soaked the first block it did not remove rust to the point of being shinny new looking metal, but it did do what I wanted & that was to loosen up the crud buildup from 100 years. Twenty years from now it will not matter to me as I am 72 now & what makes you think even gasoline type fuels will be available by 2040. As to paraphrase another poster when I questioned his rational for drilling out the block "steam" holes larger than a standard head gasket, his response was "to each his own". If it doesn't feel good don't do it. Meanwhile I will continue on with both engines, the one for my touring car here & the other for my pickup in Florida, if we ever get back this winter. I also can try to neutralize the 1st.block with baking soda after it comes back from the machine shop as it will need a thorough cleaning prion to the next step. Do you remember the 2 part caustic cooling system cleaners used up to about the early '80's, they were designed to only be in the cooling system for about 45 min. I knew guys that left that stuff in there for days before flushing & neutralizing before replacing the antifreeze. George