Crankcase split. Piston stuck. Removal ideas?

[samo_ott]

I'm working on a '56 15hp (Thanks Wayne!). I have the case split and everything removed. One piston and the crank are out. Everything is in great condition thus I'd like to try and save it. But the other piston will not budge (hence the reason for stripping it apart). I have tried gently banging it with a block of wood and hammer. (ok, a little more forceful than gently!) with no luck. I have PB Blaster soaking where ever it can... Any good ideas to get the piston out? Thanks all.

 

[SKIBUM1M]

Re: Crankcase split. Piston stuck. Removal ideas?

well worst case you will have to break the piston which most likely needs to be replaced anyway. is the piston stuck on a ridge at the top of the cylinder or is it rusted in mid stroke? if it is stuck on a ridge go to napa and get a "ridge reamer" this will cut the ridge even with the rest of the cylinder so you can remove the piston. if it is rusted in mid stroke then change your block of wood to a steel bar and bash a hole in the piston so it shatters and falls apart so you can have the cylinders bored. another possibility is if it is stuck midstroke due to rust just have the machine shop remove it since it will be there anyway to be bored.

 

[KDT1961]

Re: Crankcase split. Piston stuck. Removal ideas?

I'm working on a '56 15hp (Thanks Wayne!). I have the case split and everything removed. One piston and the crank are out. Everything is in great condition thus I'd like to try and save it. But the other piston will not budge (hence the reason for stripping it apart). I have tried gently banging it with a block of wood and hammer. (ok, a little more forceful than gently!) with no luck. I have PB Blaster soaking where ever it can... Any good ideas to get the piston out? Thanks all.

I'd take it to a machine shop and have it removed. You can do damage to the face of the aluminum head by beating on the piston, depending on the surface it is laying on. If you get it out of square, or damage the machined surface, you will have problems down the road. Those aluminum heads are very small and easy to mess up. It's not like a long block V-8 on an engine stand that can take some abuse. PB blaster is okay but is extremely corrosive. You might want to try a 50/50 mix of acetone and ATF. Much cheaper and works better.

 

[samo_ott]

Re: Crankcase split. Piston stuck. Removal ideas?

The piston is at the bottom of the stroke, closest to the crank.

Has anyone ever tried soaking the entire block in something? You'd need a lot of whatever but I think if it was under for awhile, maybe it would work.

 

[jonesg]

Re: Crankcase split. Piston stuck. Removal ideas?

machine shops go through drums of solvent, thats why they use acetone and atf mix, much cheaper and works better than anything sold in a can.

 

[samo_ott]

Re: Crankcase split. Piston stuck. Removal ideas?

I like the idea of soaking it myself but cringe when I think of how to dispose of the mixture afterwards...

 

[Chinewalker]

Re: Crankcase split. Piston stuck. Removal ideas?

I have had best results using a hydraulic bench press. I made up a jig to expose the outlet side & protect the head area of the block. I use a small chunk of aluminum dowel about an inch in diameter as a seat to press against so as to not damage the bearing surface of the rod. If the piston is going to come out intact, it will. If it is going to come out in pieces, it'll be over with quicker...

 

[samo_ott]

Re: Crankcase split. Piston stuck. Removal ideas?

Scott, I cant visualize that? Can you explain differently please

I'm going to be at Clayton on Saturday, are you going to be there also?

 

[wilde1j]

Re: Crankcase split. Piston stuck. Removal ideas?

I would try soaking in kerosene for a day. At least the stuff is not a toxic waste dump material and may well help and it's inexpensive.

I like the press idea. I made a simple press, which used a 5t hydraulic jack, some 1/2" all thread and 2" square steel box section for pressing in piston pins, etc. It would be pretty easy to come up with a fixture to distribute the load across the whole piston top.

 

[samo_ott]

Re: Crankcase split. Piston stuck. Removal ideas?

The piston top is not even close to flat. I cant see how to get a nice even force on it.

 

[Chinewalker]

Re: Crankcase split. Piston stuck. Removal ideas?

Steve,
Push from the rod side. I lay the block, head side down on my plates, with the cylinder bore area clear of the plates. I then press down from the rod side with the bench press shaft.
- Scott

 

[Chinewalker]

Re: Crankcase split. Piston stuck. Removal ideas?

Steve,
I will be at Clayton starting today. I've got Evinrude #780 there - 100 years old this year!!
- Scott

 

[samo_ott]

Re: Crankcase split. Piston stuck. Removal ideas?

Steve,
Push from the rod side. I lay the block, head side down on my plates, with the cylinder bore area clear of the plates. I then press down from the rod side with the bench press shaft.
- Scott

The rod is still connected... Makes for hard pushing! I'll see what I can do... Gonna try soaking it today...

 

[samo_ott]

Re: Crankcase split. Piston stuck. Removal ideas?

Steve,
I will be at Clayton starting today. I've got Evinrude #780 there - 100 years old this year!!
- Scott

Excellent... I'll be by to take a look tomorrow

 

[iwombat]

Re: Crankcase split. Piston stuck. Removal ideas?

You can try putting it in a tub full of a diesel and atf solution. That way you'll be able to soak the whole thing instead of hoping the PB blaster gets to the right parts. I think diesel+atf works better anyway.

 

[samo_ott]

Re: Crankcase split. Piston stuck. Removal ideas?

Kerosene worked! I soaked it for about 2 days in a bucket and then hammered it out with a 1" wood dowel. It was rusty but it looks in good shape in side. Should hone up nicely. Now I'm soaking the piston to loosen up the rings.

 

[wilde1j]

Re: Crankcase split. Piston stuck. Removal ideas?

Glad to hear it worked ...