Frozen piston - how to remove?

[AusAnzani]

Hi guys,

I am trying to salvage the cast iron cylinder from an engine that has been submerged in salt water. At present the cylinder contains a damaged piston that simply will not budge with lubricant, heat or pressure either steadily applied or blunt force. Attached to the piston is a broken cast iron or steel con-rod.

It seems the engine was righted soon after it was submerged. Water has entered the crank case and that’s where the bulk of the damage was done. The cylinder section closest to the crank case is in great condition ie as is the cylinder section other side of the piston. So far I have managed to remove the top part of the piston ie from lower ring up, so all that’s really left frozen is the collar, gudgeon and broken con-rod.

I am thinking about dropping the lot into a caustic bath ie hoping that the solution will eat away the alloy leaving the cylinder intact. Does this sound sensible approach or am I risking damage to the cylinder?
If the approach sounds reasonable / sensible, how strong should the solution be ie ratio bi-carb soda to water?

If anyone has done this before, I’d certainly like to hear from you.

Thanks & Regards

[bikerboyfife]

Yes that will do the trick for best results mix your soda then pour into head be warned it gets nippy around hands

[AusAnzani]

Thanks for the quick reply, much appreciated.

What sort of mix do I use ie how many parts soda to water? I've never used the stuff before so am completely clueless as to the mix.

BTW, have you made it to Wagga Wagga yet?

Regards,

[bikerboyfife]

Yip back from wogga did you get that piston out

[AusAnzani]

Haven't tried to get the piston out yet. Am not sure of the mix (ratio of caustic to water) so have been reluctant to try.

What do you suggest as a starting point ie how much caustic to every litre of water?

Thanks in advance & regards,

[Stelios_Rjk]

I wouldn't use caustic soda in this situation. A chemical engineer told me that a swapping occurs with the cast iron that's not so good. But I don't remember details.
I would point a torch to the internals of the piston till some serious heat occurs. (Maybe half an hour). Then cooling with coke and leaving so for a couple of hours. Again heat to hell and then some serious blasts with a wooden piece like rod close to the diameter of the piston and a heavy hammer. That means that you will push it from the side of the head to the side of the crankcase.
I have also done it the opposite way which has less crud to block the movement. But that would mean that you will find a wooden rod with diameter same as the crankshaft, place that on the con rod, with the con rod cap removed and hit it with the hammer. I had good results with both ways.. heat is the key.

[Collector Inspector]

Spiro

Can we have some pics of your hassle?

Cheers

B

[bikerboyfife]

Nice one stelios 1/2 an hour with a torch can i send you my gas bill l.o.l

[Collector Inspector]

Would that be Gazprom prices?



B

[bikerboyfife]

Gazovaya promyshlennost 44bln$us 2013 profit caustic soda £3=2lds 2 table spoons to one pint water that should loosen it give it an hour stand back it get,s hot

[Charles uk]

When they're as stuck as this one appears to be, there is a very good chance that the cylinder/bore will also have, beyond economic repair damage.

Oversize pistons, linered cylinders are into Seagull racer, levels of expenditure.

[bikerboyfife]

Very good point

[AusAnzani]

Howdy guys,

Sorry for my lack of activity. Did a work trip to China a few weeks ago. Managed to get a bug there which has really knocked me about. Haven't felt motivated to do anything since really.

Just wanted to say I greatly appreciate all the advice here. Not sure which way I'm going to go yet and don't need to make any quick decisions either as this is a spares motor only.

Once I've got it sorted, I'll post some pics.

Regards
Spiro

[haventaclue]

A lot of folk in the 'States use a 50-50 mix of acetone and automatic transmission oil,leave it awhile,48hrs,it does work on rusted stuff though I have never tried to free a piston with it.I used brute force on a Yamaha 85,it didn't work.Could never figure out why

[Collector Inspector]

Most times a press down onto the piston through a spark plug hole works well...........sometimes the piston can not be used again but a barrel is ready for further work after. If the head can be removed then very much easier as one makes a thrust plate for the piston head profile.

40 tons and all done and dusted.

Piston comes out anyway.

I have a 102 that is going to have that done shortly. Only thing wrong with it actually.

Later

B