I've joined the G749 club...

[gimpyrobb]

PSSSSHAW, dump some evap-o-rust in there and turn the key!

 

[m1010plowboy]

good to know plowboy. The one I've got is seized tighter than tight and it only been a few years since it ran-supposedly It seems as though these were common to seize up, more so than most I have worked on. Is it cause the exhaust is open to the elements, do you have an explanation? Wouldn't worth messing with if it wasn't a challenge

We've got a couple of blocks that had heads pulled by the PO so they're a rusty pool on top. We tried diesel fuel, then a mix of acetone and transmission fluid on one block with no luck. The biggest factor comes with aluminum pistons in a steel cylinder. It's so important to keep them moving so they don't have time to tell each other they are dissimilar metals. Something about aluminum carrying a +2 charge and steel (iron) iron existing in a wide range of oxidation states, −2 to +6.

It's a fascinating topic that a search on galvanic corrosion or dissimilar metals can keep a guy reading for hours, or in my case years.....because I just nod my head up and down and all the info keeps falling out.
https://www.angelo.edu/faculty/kboudrea/periodic/physical_metals.htm
https://www.nace.org/Corrosion-Central/Corrosion-101/Galvanic-Corrosion/

I don't have any answers about how to correct it in our engines because it appears that the metal begins to separate so once it starts it can't be fixed. I shouldn't say that.....I think the fix is in the pics.



I am going to try some molasses and hot water just to see what might happen but we're sure the Preventative Maintenance is to keep the pistons moving.

 

[1944mb]

Yeah and if the molasses doesn't free it up, at least you'll feel like eating it. I've never tried evap o rust that gimpy Robb was talking about, but have tried seafoam, atf, atf and laquer thinner, mystery marvel. I need to yank the head and see what's going on. Nice to see that lifting eye on the restored engine.
gimpy- have u tried that evaporust on a stuck engine?

 

[hambone]

Great looking projects, I found that the big trucks can be long term projects, been working on mine for a couple years, got 2 more wheels needing wheel cyls. installed, after this brake job, I will feel home free, only the exhaust left.