Unseize a Frozen Engine

[1970Cuda]

Hello fellow E-body enthusiasts: 

When I purchased my 1970 'Cuda project vehicle, it came with the original engine. Unfortunately, the engine is seized (I believe the original owner removed it from the car and simply left it out in the elements). The picture below is my original 'Cuda block with the pistons seized in it.

I've tried a number of products on the market that can purportedly unseize a frozen engine, but I'm somewhat frustrated in that nothing has worked.
I've been told by my friend that there is a chemical reaction that occurs between the soft aluminum pistons and the cylinder walls that makes it almost impossible to break such an engine free.

Since the picture, I've tried Metal Masters (no good) and other similar products, but nothing has budged it. As well, I tried to dissemble it  in the hopes of attempting to remove the pistons individually (that had no affect either).

Any suggestions on how to proceed would be greatly appreciated.

Thanks, 1970Cuda

[headejm]

Google "hot tank engine block cleaning". All kinds of ideas and videos on the subject. Draino, toilet cleaner, etc. My first thought was to recommend taking it to an engine machine shop that has a hot tank but I would probably try some of the ideas on the internet first. Good luck!

[chargerdon]

This year i bought a 360 LA engine block from a salvage yard that was badly seized.. $100.    I stripped it down to the block and put in a lot of good old Liquid wrench...   First with one bank straight up in the engine stand so that the Liquid wrench would go all around the piston.   Then next day rolled it to the other side and did the same thing. 

Third day i began to disassemble the pistons and had three that i couldn't get to budge when trying to drive it out the top of the block.  The other 5 came out.   i was able to get the bolts off of the connecting rods on the bad ones also, enough that i then removed out the crankshaft.   Then i got a block of wood and put on top of the first horribly seized piston and beat on the wood with a 5lb sledgehammer, driving the piston down into the bore since i counldn't get enough on it to come out the top.   its amazing how much force you can create with a 5 lb sledge...   The block of wood helped to prevent the aluminum piston from breaking.   Once i got it to move, turned the engine upside down and beat on the other side to try and drive it out as the piston doesn't have room to exit the bottom.   Got it to move some, and the repeated driving it down into the bore with the sledghammer and wooden block.   Couple of times back and forth and it popped out.   Repeated the same procedure on the other two pistons that were seized badly.     

The block LOOKED pretty bad, but, i brought it to a machine shop anyways, and the old timer there said...  "ive seen worse".     So, i said do you think it will clean up...and he said maybe at .030...only one way to know for sure.   Bore one cylinder and see how much has to come off to get clean.     He said he would try the worst of the three for $25 and let me know.   Next day he called and said...yep...at about .025 it looks good, so .030 pistons and it will be great.   Now, do you want me to hot tank it, and magnaflux to make sure the block is good...   I said yes and he did and it was fine...no cracks.   So, bought new pistons, new rods, crank, etc and turned it into a 408 stroker.   

[7E-Bodies]

I'm a major believer in Kroil. I'm never anything but amazed at what it does. Keep adding it over the course of days, weeks if necessary. My old neighbor had left a 50s something tractor outside for decades and when he finally got around to "fixin er up someday" the engine was locked solid. I showed up with a gallon of kroil and we added it to the tops and bottoms of the pistons over the course of a few weeks, tapping the pistons occasionally with a piece of oak shovel handle and a dead blow. It broke loose in a few weeks. My shop has several cans of it now. PB Blaster sucks in comparison.

[Cudamike]

I know a guy that used diesel fuel that worked.

[70 Challenger Lover]

I would imagine that once you have it all apart, you'll find the cylinders are in really bad shape. If it's never been bored out, perhaps it will clean up when you go .030 or .040 oversized during the rebuild. If it has already been bored, expect that you might be putting in a sleeve or two. I did this on a 340 recently as well as a friends 389 and they came out fantastic so don't sweat that the block is ruined forever. Where I'm going with all this is I'd beat the hell out of those pistons with a block of wood and a sledgehammer. I'd alternate between trying from the top then bottom using lots of oil in the process and it will come out eventually.

[IRON MAN]

My 68 AMX 390 sat in a garage for 31 years with a blown head gasket and coolant had leaked into the cylinders. The pistons would not move because the wrist pins were dry seized. Tried soaking the piston bores right-side up and up-side down with 50/50 acetione & ATF for a week. Then, used Kroil. Then WD40,, etc. Nothing worked. Then, made a four- foot breaker bar and bolted it to the crank flange, heated the wrist pins on the three stuck pistons with a propane torch, and inch by inch knudged the crankshaft to get to the connecting rod nuts. Was able to heat the wrist pin area enough to budge the connecting rods straight enough to pull the piston out of it's cylinder bore. When the pistons cooled down they returned to their dry seized state. May the force be with you.

[jamesroney]

I had a small block Ford from my sunbeam tiger just like that last year.  Engine left open in the rain for about 20 years.

I dropped the pan, dropped the crank, and then punched a couple of the worst pistons out thru the bottom.  I used a giant hammer, and a 3/4 inch diameter drift.  Several well placed shots between the wrist pin and the wall and I could break the crown of the piston.  Once it fractured, I could break out several holes, and separate the center of the piston from the ring "hoop."  Lots of WD-40 and a bunch of broken aluminum bits, but I saved the block at .030.  Still needed 2 sleeves for the worst ones.

There was no way that my two worst pistons were coming out thru the top...

If I had to do it again, I might use more power tools.  My hands hurt just thinking about it...

[Brads70]

My 401 that sat for 25-30 years( with about 5000 miles on it)  I just rebuild was seized also. I went at it from the bottom and top of the stuck piston. I found the stuck piston by using the hammer handle to rock the piston in the bore, the ones (2) that didn't rock were the stuck ones.  WD40 , motor oil  , penetrating oil and a wooden 2x2  tapping it till it moved. By the end I could turn the rotating assembly over quite easily. But after removing the pistons found the rings had seized up on the piston grooves. I did manage to clean everything up on all the pistons, put new rings and bearings, ball honed it and assembled it.  It still is the stock bore  for a 401.  I got lucky!  Actually found one piston ring land than was tight in one spot from the factory. Carefully filed it out till the ring moved nice. I'm guessing someone dropped it before the engine was assembled.   

[JS29]

I used kerosene and automatic transmission fluid mix, pored it into the cylinders. Engine was still in the car, let it set a few days. with a breaker bar i kept rocking it back and forth. after it started to move a little i kept going counter clock wise a little at a time. about a week of that and i could turn it a full revaluation. after it was freed up i was able to start it. 

[torredcuda]

The two ways I use to un-freeze rusted parts are PB Blaster and wax/heat. PB Blaster method is to spray once or twice a day for at least 3-4 days, the length of time is key for it to work, the longer the better and keep it as wet as possible. Second method an engine builder taught my friend who worked for him - take paraffin wax (candle wax will do) , heat area with propane or map gas and melt the wax in between the parts. The wax acts as a lubricant and helps free up the parts and helps them slide . The engine builder uses it to free up rusted blocks including flat heads where the valves are stuck and be realy tough to get out, I have tried this on a  lot of things and has always worked.

[Brads70]

The two ways I use to un-freeze rusted parts are PB Blaster and wax/heat. PB Blaster method is to spray once or twice a day for at least 3-4 days, the length of time is key for it to work, the longer the better and keep it as wet as possible. Second method an engine builder taught my friend who worked for him - take paraffin wax (candle wax will do) , heat area with propane or map gas and melt the wax in between the parts. The wax acts as a lubricant and helps free up the parts and helps them slide . The engine builder uses it to free up rusted blocks including flat heads where the valves are stuck and be realy tough to get out, I have tried this on a  lot of things and has always worked.

I often use birthday candles for the same thing. I had an old friend show me that trick too, works well!

[1970Cuda]

Wow, great advice everyone! I really do appreciate all the suggestions and experience that you all have passed along to me. I think I have a new game plan on how to proceed with breaking this engine free. I like all the ideas, but since I've already started to dissemble it, I'm somewhat limited in how to proceed.

I'll try the penetrating oil again (I used my Gibbs Penetrating oil before, but that had no effect, so I'll try Kano or PB Blasters) and some physical persuasion. And then if that doesn't work the heat and wax treatment (I've never heard of that before).

On the heat and wax idea, do you heat the piston area and simply apply the wax to the cylinder walls or how does that work? I'll try to YouTube it as well.

Again, thanks everyone for your valuable suggestions.

[torredcuda]

You want the wax to seep in between the parts so I would heat right where the piston meets the cylinder wall, I would melt it from both top and bottom.

[chargerdon]

guys...fyi...

look at https://www.youtube.com/watch?v=xUEob2oAKVs   

This is a controlled test for freeing rusted bolts using, wd40, kb blaster, kroil, tranny fluid mixed with acetone...  and a couple of others, and comparing them all to plain heat.   In this youtube...good ole liquid wrench beat them all, and had the plus of being about the cheapest as well.   Heat from a torch worked about as well as the liquid wrench as well...but...of course you cant always apply heat.     

Its liquid wrench for me !!