I have a 5.3 aluminum block engine which would not spin when I bought it. As I have been disassembling the engine, I have not seen anything catastrophic. I believe it is just from sitting with water pooled. I blew the crud out with shop air, and have pb blaster pooling in 4 cylinders. Any advice to get this motor apart?
Marvel Mistery oil or 50/50 ATF acetone mix. You might have to let it sit for a few days before you can start trying to turn it back and forth.
Slippery said:Marvel Mistery oil or 50/50 ATF acetone mix. You might have to let it sit for a few days before you can start trying to turn it back and forth.
+1 for Marvel mystery oil.
Patience is the most important tool.
Soak with fluids, the thinner and more stinkier the better (ATF, nah. PB Blaster, why not just use water? Go for kerosene or Diesel or paint thinner or gasoline), wire brush what you can access. Try to rotate occasionally, once you start to get some wiggle room, flush and soak some more.
I had a 2.1l Audi turbo engine that needed six months of off-and-on ministrations to get to rotate. I really REALLY wanted to save the pistons. Getting the rings out of the pistons without damaging them was another trip!
Or, if you don't care about the pistons because you plan on having it bored to 5.7 spec, unbolt the rods you can access, reach in with a reciprocating saw to cut the rods you can't, remove the crank, beat the pistons out with a punch and large hammer.
Thanks for the advice. I grabbed some marvel mystery oil, and will start there. 
And when you CAN get movement- even just a little!- don't attempt to make a rotation. Instead rotate as far as it'll allow, then return, so that way you try to steadily improve and work through whatever is keeping it from rotating.
Also a consideration for GRM; how about a mild acid in the pistons to help brake down rust? You can get powdered citric acid for literal pennies and it's weak enough that it shouldn't pit anything. If they can empty and rinse the cylinders that could be a good option.
Patience. That's the key ingredient to success. Since I got older and learned to slow my roll, my success rate has skyrocketed.
Marvel is pretty good so you've got that headed in the right direction. There's a lot of antique tractor dudes that fix absolutely hopeless machinery and they all adore Marvel Mystery Oil to break loose those stuck old engines.
I'm into antique bicycles and they often present challenges due to sitting outside in the weather for 50 years or so.
Only an option if you can work quickly, but muriatic acid will dissove rust a lot faster than it will dissolve the base metal.
Will damage the pistons if you can't neutralize it fast enough. BUT I have used muriatic for things like removing rust from inside steel fuel rails and, my favorite, removing heavy rust scale from inside engine water jackets. Poured a gallon of it directly into the radiator, topped off with water, started running. The chemical reaction was strong enough that it started boiling over fairly quickly. Didn't damage the aluminum heater cores or aluminum cylinder heads, but working quickly here is the key.
Pete. (l33t FS) said:Only an option if you can work quickly, but muriatic acid will dissove rust a lot faster than it will dissolve the base metal.
Will damage the pistons if you can't neutralize it fast enough. BUT I have used muriatic for things like removing rust from inside steel fuel rails and, my favorite, removing heavy rust scale from inside engine water jackets. Poured a gallon of it directly into the radiator, topped off with water, started running. The chemical reaction was strong enough that it started boiling over fairly quickly. Didn't damage the aluminum heater cores or aluminum cylinder heads, but working quickly here is the key.
If anyone does this- which there's good reasons to!- neutralize with ammonia, not with baking or washing soda. You NEED ammonia because the neutralization reaction won't make a mineral salt that'll precipitate into the passages, which WILL happen with something like baking soda. Learned that cleaning concrete for my garage.
Oh, NOW you tell me! 
I used baking soda, but after a thorough full-loss rinse out of the cooling system (IE removed the upper radiator hose/thermostat and plugged the garden hose into the radiator's inlet and flushed with the engine idling) before neutralizing with baking soda. Which at that point was probably just more to make me feel better than anything chemically useful.
What about just soaking with evaporust? Not as hazardous to other materials.
I used the ATF/Acetone trick to free up a Pontiac 350 that hadn't run in 3 decades and was locked up solid. Pulled the spark plugs, pumped it full, let it sit overnight, added more, let it sit again, then slowly began wiggling it back and forth and adding more. Like others said, patience is key if you don't want to break rings or gack up bore walls. Worked absolutely terrific.
I'm learning (ammonia thing, specifically.)
Came here to suggest heat-like MAPP gas heat, not Acetylene. That said, I love the videos where they chuck the whole block in a fire.
Apexcarver said:What about just soaking with evaporust? Not as hazardous to other materials.
Evaporust works via Chelation; the progressive darkening it takes on is from the Iron being removed and left in suspension.
As long as you're okay with the cost, you can absolutely soak it in Evaporust.
What about white vinegar? I saw a video from UTG where he tested a bunch of stuff on stuck rings, and white vinegar seemed to be the most effective. I know it works on rust. Not sure if typical 5% or the heavy duty 30% cleaning stuff would be more appropriate.
02Pilot said:What about white vinegar? I saw a video from UTG where he tested a bunch of stuff on stuck rings, and white vinegar seemed to be the most effective. I know it works on rust. Not sure if typical 5% or the heavy duty 30% cleaning stuff would be more appropriate.
White vinegar is super low concentration as acids go, so any rust removal will take serious time. Also when you compare it to say, bags of citric acid, the citric acid not only wins out by being far cheaper but you can also titrate the acidity to what you need (to a max of 3-4pH or so).
On the plus side- store bought vinegar won't pit the metal because it's just so weak. So if he used vinegar by pouring it into a cylinder and leaving it for days, that's a definite bonus.
Pete. (l33t FS) said:... I have used muriatic for things like removing rust from inside steel fuel rails and, my favorite, removing heavy rust scale from inside engine water jackets. Poured a gallon of it directly into the radiator, topped off with water, started running. The chemical reaction was strong enough that it started boiling over fairly quickly. Didn't damage the aluminum heater cores or aluminum cylinder heads, but working quickly here is the key...
I assure you that muriatic (hydrochloric) acid goes after aluminum with a vengeance. "Working quickly" isn't just a suggestion, as the reaction is exothermic, generating a great deal of heat that feeds the reaction. If you use the stuff, flush it out really well, followed by another flush containing backing soda to counter the acid. Otherwise, say goodby to any thin aluminum in the system.
In reply to GIRTHQUAKE :
Makes sense. I mean, I'm not even remotely qualified to judge, but it seems to make sense to me. FWIW, here's the video I mentioned - as you can see, it's individual pistons in various liquids, rather than locked in the cylinders:
In reply to GIRTHQUAKE :
If I was going to use a mild acid, it would be vinegar.
In reply to kb58 :
What usually seizes the engine is not just the rings rusting to the bores, but also the rings rusting to the pistons and a rust clog on the bores themselves keeping things from moving.
There will be bore damage. Not ideal but usually not enough to prevent compression.
I have seen a couple times the pistons damaged from the rust on the rings expanding and crushing the ring grooves, leading to excess ring side clearance, which causes flutter and poor sealing. Again, not the end of the world from a dirt floor and sandals "make the engine run" perspective, not great from a performance perspective.
But yeah, working quickly means working quickly 
I definitely would not use acid as a first resort.
Dry ice or liquid nitrogen on the back side of the piston. Liquid nitrogen is better. Hit with hammer and shatter the piston.
Or same as above but add some heat around the cylinder (not to much) and see if it gets it un stuck enough to get moving/get it out.
After all this it may be cheeper to get another core.
Appleseed said:In reply to GIRTHQUAKE :
If I was going to use a mild acid, it would be vinegar.
Get the 30% stuff at Home Depot or some local hardware stores have it.
Not the grocery store stuff (5%)
I saw a guy do a test with Coca Cola. Dropped a rusty bolt in some and came back two days later to a huge difference in appearance of the bolt. He claimed to have used it to free frozen engines, but I have never tried to emulate him.
Coke is also great for cleaning battery posts
I tried mmo on one bank of cylinders. Since the heads are off, I am working one side at a time. Two cylinders had emptied, so I took that as a good sign since the liquid is getting past the rings. I am now letting a 50/50 mix of acetone/atf sit in the other bank. After a day or so I'll give it a wiggle, and if it doesn't move I plan to switch to vinegar for a couple days and see what happens.
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