How to move rusted pistons in the engine block

[Krzysztof]

Dear Experience Fans and Experts

I'm struggling how to safely pull out two pistons from engine block (not M30) which have rusted badly in the block.

For me the block is not important to be saved as it is cracked but I would like to regain the pistons.

After several instructions I have applied respective actions:
1. Use anti-rust agent/oil on top of both and let is soak into the rings/pistons => it was soaking for a long long time - no help
2. Fill the cylinder with vinegar and leave for day/two => I keep it even longer. All surface rust disappeared nicely but pistons are still there and can't be hammered out (with relatively controlled punches)

I do not want to use too much force, not to damage the pistons.

I have also seen method with a mixture of gas and oil to burn it inside the cylinder to extend them thermally but I was not sure this is the right way to use.

Also pressure added from the below with the wooden stick was presented but not sure it will not damage the pistons.

Have you been facing similar problem in the past?
If so, which method worked for you?

 

[tferrer]

Are these custom/special pistons? I'm assuming you want to copy them?

 

[Krzysztof]

These are special/custom pistons. This is the reason I want them out undamaged.

It would be "too expensive" to scrap them, so I need to save them from the cracked engine block if possible.

 

[eriknetherlands]

if all else fails, cut the engine block away around the pistons?

 

[Wladek]

A lot of lubricant & harbor hydraulic press.

 

[JFENG]

Dangerous but how about installing a head, filling the cylinder up with automatic transmission fluid+acetone, let sit for a week, pressurize the cylinder via the spark plug hole and a compression tester adapter (fill the combustion chamber mostly with motor oil).

 

[tferrer]

They'll likely be unusable so all you'll need is one as a pattern to have repopped. Get a bigger hammer...

 

[Stevehose]

Heat up the cylinder walls with a blow torch then give the hammer another go

 

[JFENG]

They'll likely be unusable so all you'll need is one as a pattern to have repopped. Get a bigger hammer...

If you beat on the tops there’s a chance you’ll break it above the top ring land. Not a problem if your making new ones.

The shade tree in me wants to say whack it from below, against the rod big end. But next you’ll say the rods are $3000 titanium and you also want to save them.

BTW: I’ve had the best luck with Seafoam Deep Creep for loosening up stuck engine parts. YMMV.

John

 

[boonies]

Time is your friend with the penetrating lubricants, soak and repeat. @JFENG has an Interesting thought about working from the bottom.

 

[Krzysztof]

if all else fails, cut the engine block away around the pistons?

Thanks Erik. It is some way but I think I'm not patient enough for this

 

[Krzysztof]

A lot of lubricant & harbor hydraulic press.

Thanks! That was also presented on one of YT channels. It might be the way.

 

[Krzysztof]

Dangerous but how about installing a head, filling the cylinder up with automatic transmission fluid+acetone, let sit for a week, pressurize the cylinder via the spark plug hole and a compression tester adapter (fill the combustion chamber mostly with motor oil).

Very interesting. I would love to test that having another engine where potential effect will not be potentially to expensive. Good idea for some famous YT channel. Or maybe someone did that? I would love to experience that from larger distance.

The antirust agent was sitting very long and later vinegar ... I was not considering pressure from the top... Creative.

 

[Krzysztof]

They'll likely be unusable so all you'll need is one as a pattern to have repopped. Get a bigger hammer...

That's my fear. Hammer or press method is probably on my latest item on "to do" list and will probably work with a damage of the piston center or (best case) ring slots.

Closer and closer to heat treatment (gas+oil) and pressure after some time. It would be even easier if the block would crack on the cylinder.

 

[Krzysztof]

Heat up the cylinder walls with a blow torch then give the hammer another go

Another vote for heat treatment. I'm almost convinced that should be another step. Thanks!

 

[Krzysztof]

If you beat on the tops there’s a chance you’ll break it above the top ring land. Not a problem if your making new ones.

The shade tree in me wants to say whack it from below, against the rod big end. But next you’ll say the rods are $3000 titanium and you also want to save them.

BTW: I’ve had the best luck with Seafoam Deep Creep for loosening up stuck engine parts. YMMV.

John

The rods and pistons are worth much more than the block as it can't be welded (the block is not an usual one but ... gone).

I'm wondering what will "eat" the rings and cylinder but not aluminum.

I know it might be a challenge without a success but I'm not in a hurry at all, so great opportunity to try different things before the "force will be with me"

Have you used "Seafoam Deep Creep" based on Project Farm YT channel I'm watching from time to time? It might be difficult to find it in Europe without Amazon help.

But this could be a way to check some engine flush chemistry as well.

 

[Krzysztof]

Regarding working from the bottom I found a good way - wooden block/stick with the cut area where the rod is located. It is than distributing the force from the hammer hits on the piston bottom which is the most durable part of it.

 

[JFENG]

Sea Foam Deep Creep: mix automatic transmission fluid with acetone (1:1).

 

[Krzysztof]

Sea Foam Deep Creep: mix automatic transmission fluid with acetone (1:1).

Thanks a lot. I was not aware it is so easy to make.

 

[sfdon]

Parts washer first…

Start with two closest to the deck…

Use an aluminum dolly and tap them out.
Now use honing tool to clean other four bores
With a washed hot engine and two pistons gone and nothing but clean bore ahead - they should come out.