Might try a different concoction first. Mix acetone and atf. Pour that in the stuck ones and let it sit a while. I believe that the mix that is used to help free turbine housings from the CHRA. Sounds like the rings may be rusted to the cylinder wall. Might put a block of wood on top the 4 pistons and give a few whacks with a hammer to see it that helps. Don't beat it to death. Just a shock to break that grip. Third option may be heat with a torch. Don't want to melt the piston, but get it warm enough to expand a little to break the adhesion. This is all assuming those pistons aren't frozen to the cylinder wall by the aluminum. Sounds like this thing must have been stored in a damp environment. Rust on cylinder walls tends to make one think that. Those cylinder probably had their intake or exhaust valves open and the turbo wasn't sealed shut. There's also the draft tube on the other side that lets air in. Regardless, looks like it's up for a complete rebuild. Another issue that could be in play could be cracks in the head. Have you examined it. The early 5.9 had 9mm injectors and those heads were notorious for cracks. Could have had some coolant leak into the cylinders but that's probably not the issue. Coolant usually doesn't support rust. Did you note any water in the oil pan or did it even have oil in it?

 

I would drop crank and use head studs and a gear puller across bore to "wine press" the piston/rings loose. Or tap with a wood or plastic softener and hammer to try to salvage pistons. I would push them whatever part of the cycle they were closest to, to lessen the bore damage. Probably a better way to go but my 2c.

 

Thanks guys. These were ideas I hadn't come up with. Then engine already had the turbo taken so I believe your spot on with the theory of poor air sealing.

I will try the new mix idea as you suggested first. This is a long term project so I am in no rush.

Rapps on the piston with a soft hammer is a great idea too.

I haven't went over the head with a magnifying glass, but it looks to also be in good shape. I will be at least doing the valves and replacing injectors and maybe new springs.

As for heat- ill save that for a more 'down the road' resort ? As I only have access to your garden variety hand held propane torch anyway.

Fingers crossed I guess eh. Thanks for the quick reply gents!!!

 

Yeah, sounds like your problems were caused by poor storage prep. If the area where you live has high humidity that makes it worse. Do the pistons have markings on them to tell you is the previous rebuild changed piston size?

 

Can't answer that either as of now unfortunately. But will take a closer look tonight to see if they indicate aftermarket/over sized.

Cylinders 1&2 look great; easily visible crosshatch, no fingernail catch at top, no scarring.

Cylinders 3&4 are at the very top of their stroke so although I can't see the walls, I'm operating on the hope that they share the quality of 1&2 by having been preserved/ sealed by the piston themselves.

5&6 are at near or complete bottom of their stroke. What makes me hopeful about the cylinders is that the rust seems more to protrude from the walls, than have pitted or went 'into' the cyclinder walls. The rust is almost like barnicals. So I'm hoping they will kind of be able to be loosened and cleaned off relatively easy.

I'm headed into town soon to pick up the acetone to mix.

 

I was going to suggest you check to be sure the cam locking pin wasn't engaged, but if #1 piston isn't at TDC it can't engage. Only other possible would be either the KDP or one of the bolts behind the front cover had gotten into the gears. Let's hope chemical mix breaks the rust.

 

I did think to check the tdc pin was not engaged. But haven't actually pulled the front cover yet :0. Seller told me the kdp was tabbed when I asked. Hopefully I'm not in for a nasty surprise when I yank the cover.

Anyways dudes a thousand thanks. You blokes have provided directly useable help here. Cheers.

 

The acetone and ATF mix is the best penetrating oil I've found also. Since it doesn't sound like your in a real hurry, I'd pull the crank then spray the mix into the cylinders, have a chunk of 2x4 and a hammer sitting by the motor. Every day when you walk by use the 2x4 and hammer to see if the pistons will move. If not spray them again and try the next day.

 

When you pull the front cover you'll have to replace the front crank seal. Can't reuse those. You're probably going to have this one down to bare block anyway. When you pull the cam, be sure to put each lifter in a separate bag and label which hole it came from. If you mix them up you either have to have them reground or replaced. Although the bearings should be good, might replace them anyway. They aren't that expensive. If you want a bit more durability, might send them to Polydyn in Texas and have them coated. They can do pistons too and I've heard their costs are very reasonable.