Can't slide cylinder off piston of STIHL MS 362

[Smitty Smithsonite]

Any thoughts on how to actually get it out?

If you already have a new piston and cylinder, might as well beat it out of there with a rubber mallet. Could always heat the cylinder up, too, but this will complicate things a bit.

 

[lostone]

TBH the way I would get it out would require tearing the bottom end apart as well so I will see what others have to say they would do in this situation.
I'm sure there is a trick I am missing.
With that said my way would be pulling the piston down as far as it could go and having at the top of the cylinder about half way down the exhaust port with a hacksaw and decapitating the cylinder, push the piston back up through what is left and dig out what is left of the rings. The problem with this way is the shavings could end up in the bottom end even being careful and packing off around the rod with material.

 

[Bob Hedgecutter]

You want to get the topend off and separate the piston from the cylinder in some kind of perhaps pipedream that one or both fairly major components can be saved.
I would suggest that whatever is causing your problems has probably damaged the internals beyond repair- we just cannot see in there yet to confirm.
You could use a pump oil can to drizzle a fair bit of whatever oil you have laying about down the sparkplug hole, swill it about and then start twisting and bouncing the cylinder side to side and up and down- you might just luck out and manage to jostle a position where whatever it is slips past the transfer it is catching on...... the big word there is MIGHT.
I like the idea of splitting the case, remove the crank with the piston still in the cylinder and then destroy the piston from the underside- you were going to do bearings and seals anyhow?
Worst case scenario- what is jammed in there is a bit of the big end bearing cage that has done a few circuits through the transfers and the bottom end is as roached as the top.

 

[Nex]

If you haven't tried it yet, try rotating the head while carefully pulling and see if you can rotate the piston in the can until you either feel where it snags or where it let's go. Be careful though so you don't put too much pressure on the crankbearing.

 

[T.Bird]

Be careful though so you don't put too much pressure on the crankbearing.

I do like the idea of trying to twist it off, but I have been nervous about this^^

 

[Smitty Smithsonite]

Remember the crank bearing can handle any up and down loads much more than you could put on it. It's the side-to-side loads to be a bit careful of.

I'd get some gloves, heat up that cylinder, then take out all my frustrations on it with a stiff rubber mallet.

 

[Joisey]

An air powered 3 inch cutoff tool, like used for mufflers would make short work of the cylinder. Harbor Freight sells them cheap, but the tool and a pack of 3 inch discs, pack the crankcase opening with oiled rags, don safety glasses and have at it. Before doing that, I'd try penetrating oil, and if that doesn't work, wrap the engine in a trash bag and put it in a deep freeze for two days. Remove from freezer and try removing the cylinder. If those fail, cut it in two.

 

[PV Hiker]

I like the idea that somebody mentioned using a cut up coke can (or beer can if that what you have).

The method would be to have a thin stiff material that can be slid up to the stoppage. Push the piston back in a bit and follow it with the stout material. While pushing up with the stout material, try to pull out the piston. Theory would be that you can reshape the stoppage point enough to get it past and out.

 

[PV Hiker]

Not everyone has the hand strength of an Orangutan though?
How about a pair of custom cut tapering hardwood wedges between crankcase and cylinder flange? Keep knocking the boggers in until something lets go!
If you could get the crank to TDC and the piston down as low as you can, could you slip a split beer can between piston and cylinder enough to work past whatever is catching?

Ha, found it... @Bob Hedgecutter mentioned it.

 

[cookies]

push the piston to top dead center, rotate the cylinder 90 degrees and rapidly try to snatch the cylinder off,rinse and repeat, if this fails remove a piston pin clip and slide the pin out, you may have to cut the cylinder to gain access.

 

[Pythagorus]

I'd be thinking about the circlip and wrist pin...circlip come out and jamming ...the cylinder at present is won much more at top than bottom..or if you prefer..below ign travel.......of course ring suggestions already made are gnerally sensible. I'd have the case split and do a complete tear down and inspection and measure of all active components...otherwise you'll beat it to death and still have to pull it to bits.

Cars are sensible...pistons go in from top...and out from top. Whether there is enough wear to push the piston to top then slide a ring compressor over it to hopefully get it past the 'catch' ....or push thin brass sheet down around it without lacerating your hands..only you can tell. The latter allows you to move the sheet down with the piston.

 

[T.Bird]

Thanks for all the ideas and inspiration everyone. For those keeping score at home, I got it off! It was actually very anticlimactic, which is fine with me! When I finally got around to taking off the ignition module and air guide shroud I had way more room to work. Enough so that when I turned the whole thing upside down there was room to bash the cylinder off with a dead blow mallet. Sure enough, both rings were broken!

Now I'm off to the local power equipment shop (which claims to service Stihl products) and see if I can convince them to split the crankcase for me so I can launch into the bottom end rebuild.

 

[Mad Professor]

Thanks for all the ideas and inspiration everyone. For those keeping score at home, I got it off! It was actually very anticlimactic, which is fine with me! When I finally got around to taking off the ignition module and air guide shroud I had way more room to work. Enough so that when I turned the whole thing upside down there was room to bash the cylinder off with a dead blow mallet. Sure enough, both rings were broken!

Now I'm off to the local power equipment shop (which claims to service Stihl products) and see if I can convince them to split the crankcase for me so I can launch into the bottom end rebuild.

 

[T.Bird]

Oof… tough crowd.

 

[pioneerguy600]

Thanks for all the ideas and inspiration everyone. For those keeping score at home, I got it off! It was actually very anticlimactic, which is fine with me! When I finally got around to taking off the ignition module and air guide shroud I had way more room to work. Enough so that when I turned the whole thing upside down there was room to bash the cylinder off with a dead blow mallet. Sure enough, both rings were broken!

Now I'm off to the local power equipment shop (which claims to service Stihl products) and see if I can convince them to split the crankcase for me so I can launch into the bottom end rebuild.

Catching the intake port, questioning minds need to know.

 

[Smitty Smithsonite]

Looks like she seized briefly, then the ring(s) broke.

 

[Mad Professor]

Is cyl plating or port margins toast?

 

[T.Bird]

Looks like she seized briefly, then the ring(s) broke.

Sounds believable, but help me out here. What is it that leads you to thing that?

I'm afraid I'm not going to be much help to the inquiring minds out there as far as providing answers to what was wrong. With this being the first used p/c I've ever laid eyes on, I'm really not sure what I am looking at. To my inexperienced eye, it doesn't look like there is much grievous damage or scoring and the inside of the cylinder feels pretty smooth to me.

 

[lostone]

I'm afraid I'm not going to be much help to the inquiring minds out there as far as providing answers to what was wrong. With this being the first used p/c I've ever laid eyes on, I'm really not sure what I am looking at. To my inexperienced eye, it doesn't look like there is much grievous damage or scoring and the inside of the cylinder feels pretty smooth to me.

Take a better pic inside the cylinder, this is what we are looking for. Also to see if the plating has been worn/torn/chipping away around the ports as the rings where catching. Run your fingernail over area's like the arrow is pointing at cross ways of the pattern and see if you can catch your nail on it.
It's hard to tell from pics sometimes but we are looking for transfer, gouges and damage to the lining. Also if the rings damaged the chamfers on the ports as well.

 

[lostone]

Here's an example. This is a China cylinder that I was learning on for porting purposes, ignore the shavings in there I was playing after I took it off with polishing and other stuff. This cylinder actually did fine and I changed out for a LRB pop up piston and still had a massive squish but without a lathe I couldn't lower it and the top of the intake port snagged a ring on the LRB pop up which had the ring grove cut lower than the original piston, when turning the saw over by hand after assembly it felt fine but after the first test run I went to do a restart and I felt the rings grabbing. This is the result, the deeper gouge you see is through the plating and if this cylinder where left in place it would have chewed itself up in no time at all.