piston is seized, cant get cylinder off

[Duster8]

so i pulled the engine out of my superjet, took the head off, and took all the bolts out that hold the cylinder on. it will float a little but wont come off b/c the piston wont budge. ive hammered on it a little and sprayed PB blaster on it a few times, but its stuck pretty bad. is there a tool to remove seized pistons? any other ideas?
thanks
-dustin

 

[Speedfreak]

Have somebody pull up on the cylinder as you beat the snot out of it with a chunk of wood and a BFH. I haven't seen one that my 3 pound craftsman hammer won't move

There is a piston pin puller. Which you will need to pull the wrist pin, well more than likely if the piston is stuck that bad the wrist pin will be a muther to get out also

 

[Duster8]

i hit it pretty hard with a BFH but i was afraid that might break the bearings in the bottom end. dont want to have to rebuild that too... are those roller bearings?

 

[Speedfreak]

They are roller bearings not needle bearings. If you have to hammer on it hard enough to damage them then you will destroy the rods first. The crank can handle a TON of pressure. Just look at the pressure a race motor sees just at idle. 200 Pounds of compression and then an explosion that blows the piston back down.

 

[douglee25]

If the piston is that seized in the motor, you may have to physically break the piston. Try soaking the top of the piston with PB blaster first. Then use your BFH.

Doug

 

[RDH]

try heating it up with a torch then hittin it.....torch works for me on everything

 

[keefer]

You can use a small bottle jack to press the piston out. I have done this on a dirt bike once that was seized up tight. You will have to secure the jack & engine between two fixed points that will not give. Use a small block of hardwood between the jack ram and the piston. As long as the crank is not at TDC or BDC it should move as you press the piston out and not damage the rod or bearings. You will need to be most careful when driving the piston pin out as it will likely be a bear as well. Be sure and support the piston side to side on the same axis as the pin so that when you drive the pin out the piston takes the energy and not the rod. You can bend or snap the rod if it takes the force of the hammering when driving out the pin..

 

[kawirider00]

dont heat it, the piston will swell, just put pb on top of piston, have someone hold a 2 foot 2x3 and hit it with a post mall, once it breaks free have someone hold the motor a little off the ground and pound it out all the way

 

[nikad58]

I have never seen a piston stuck that bad unless.. the pin slid out and now is stuck in a transfer.. if thats the case.. best of luck to you.. sometimes you need to cut the rod off to save as much as you can..

 

[Speedfreak]

If the pin is that hard to remove get a pin puller. I think they are under 20 at dennis kirk. Well worth the money. I fixed mine to so that I can use a ratchet on it and pull the pins that much faster. There is no need to hammer the pin out no additional stress on the rod. It is one of thoes tools that actually work.

 

[nikad58]

If the pin is that hard to remove get a pin puller. I think they are under 20 at dennis kirk. Well worth the money. I fixed mine to so that I can use a ratchet on it and pull the pins that much faster. There is no need to hammer the pin out no additional stress on the rod. It is one of thoes tools that actually work.

and drill a hole through the side of the block ? :bigeyes::bigeyes:[

 

[Duster8]

If the pin is that hard to remove get a pin puller. I think they are under 20 at dennis kirk. Well worth the money. I fixed mine to so that I can use a ratchet on it and pull the pins that much faster. There is no need to hammer the pin out no additional stress on the rod. It is one of thoes tools that actually work.

maybe he means after i get the cylinder off?

 

[RDH]

dont heat it, the piston will swell,

ya the piston will swell if you heat the piston! if you heat the cylinder it will expand and the piston will slide easier

 

[eel]

Has it seized from rust? Or what?

 

[Duster8]

beat the hell out of it today and finally worked it loose. yea it was all rusty and the bottom end looks as bad or worse. even with the cylinder off the crank will only move slightly in each direction. all the bearings seem to be locked up. i dont know what happened, but water was getting in the cylinders somehow.. and sand too.. looks like this engine is shot. also, the sleeves are 85.4 mm. they look pretty thin by the ports. if i rebuilt the bottom end, could i even reuse these sleeves and go to 86mm? its a 701 62t

either way, looks like im done for the season. im pretty bummed, and im already about broke..

 

[douglee25]

Sounds like a bad head o-ring or bad head gasket.

Doug

 

[Duster8]

could be. there was a bunch of water and grit in the exhaust pipe too, and everything was full of sand...
if the head gasket was bad you would think just a little wouldve gotten in since the head and cylinder stay pretty dry. but maybe it was letting freshwater in but it didnt really make a problem until it was saltwater...

 

[kawi650]

throw some marvel mystery oil in there i know someone that try that and freed the pistons....maybe it could work for you

 

[#ZERO]

Use a bigger hammer. :smashfreakB:

 

[eel]

When I get one that's that water damaged, I pull the reeds and use the oxy to cut the rod. You can't get a cutting tip in there so I use a normal tip, get it glowing orange to white hot then turn up the oxygen. The rod parts almost instantly.

Then you can put the cylinder in the press and most of the time remove piston without further damage.