Getting stuck pistons out

gggGary

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Pulling down a 77 with some very stuck pistons. They are up near the top of the stroke. turning the crank is moving the cylinder up and down about 3/8" (10mm finger boy)

rust buster sprayed on a couple of times. solid hits on a hardwood block then some smacking with a brass mallet. nothing yet.
I have some more irons in the fire, but hey maybe someone has a neat trick I haven't heard.
I will just toss the pistons but hope to keep rods and cylinder in good (rebore) condition.
pics in next post. :wink2:

Engine looks good inside otherwise.... so far. Valve ends, adjusters, no dimples or chips. Engine was in a group parts buy, someone gas wrenched the top of the frame off cutting through the mounts just to get the cam out, then threw the engine back together.


77 parts engine.jpg
 
Hey Gggary! the BEST stuff for rusted rings is Kroil. I mean, it is THE best. Kroil. It penetrates and free's metal up like NO OTHER. Don't know WHY, don't know HOW, but it IS the poop! When you apply it tho, maybe you should contact S2R FIRST to find out if you should use millilitres, CC's, ounces or what. Fingerboy, HA! I like that!
 
Easy......Evaporust. I just freed two engine after only a couple days with this soaking the rings from above. Just pour in enough to cover the piston and BE PATIENT. Let it work and tap them out of the bore a couple days later. Look for it at local auto parts places (Advance Auto, O'Reily, etc)

https://www.evaporust.com/

Evaporust sucks and is terrible and doesn't work. It's the equivalent of old honey mixed with gorilla glue... AH-HAAA! :D
 
Yeah, I'm just trying to get a rise out of S2R, to cajole him, to entice him, to incite his rage. It rarely works. I just read up on the evaporust product and I think it sounds like a pretty good product. S2R wins. Again. Sigh. And he didn't even have to get involved. GROUSE!
 
" BE PATIENT" WTF???? Me??? Oh wait I get it now, BE PATIENT = bigger hammer! Cool.


xs stuck pistons and xs1 worm 005.JPG

xs stuck pistons and xs1 worm 003.JPG


These weren't that bad, just the RH was stuck, bit of wood block work and it's moving. nearly out the bottom now. Just making some taller blocks to hold the cylinder higher so the pistons don't hit anything on the way out.
 
Good stuff s2r
Electrolysis is line of sight and not so compatible with aluminum.
A problem is that rust is bigger than steel so the rust process expands and jams the parts together. Not so sure on the conversion from rust to whatever evapo rust forms. Then you have the carbon deposits, who knows what if anything they react with.
Aluminum corrosion is even worse that way it expands and sticks parts together real good. Getting the bearings out of salt country aluminum front wheel drive hubs is brutal.

Guilt: I beat those poor pistons out and the last little bit was an SOB! I think maybe the beating expanded the top of the piston..... I'll be looking at the small end of the rods today. Should of quit and gone upstairs sooner. The rest of the engine looks really good, since the front was cut off the frame I'll guess a hard front hit sent it to the wreckers.
 
I have a really stuck motor I picked up last winter. I soaked it all summer with PB Blaster and it's still stuck. I picked up some Evapo-Rust last week. Glad you mentioned that when it turns black, it's no longer working. Mine has done so. I'll have to blot it out of there and add some new flesh stuff. Nice to know it's doing something.

I plan on building one of those "pusher" assemblies like mentioned in that other thread but it will be more heavy duty. I will use steel for the top plate instead of wood, and lengths of heavy all-thread for the pusher screws. I will double nut them through the plate so the lengths are adjustable for pistons stuck at different heights.
 
I plan on building one of those "pusher" assemblies
I will use steel for the top plate instead of wood, and lengths of heavy all-thread for the pusher screws. I will double nut them through the plate so the lengths are adjustable for pistons stuck at different heights.


:thumbsup::thumbsup:

Me too. post up pics! There are a few gotcha's to get one that works for all the heights the pistons get stuck at AND gets them all the way out the bottom..... some sort of cup is needed to direct the push away from the thin crown area. I think it's important to be able to push both pistons kind of evenly so the rods don't get stressed by uneven movement down the bores.
 
The evaporust is a chelation process, probably using one or more organic acids, perhaps citric or oxalic acid....


Electrolysis changes the rust to magnetite that no longer is molecularly bonded to the iron, it is readily brushed off.
 
I'll go bigger, probably 3/4". I think I have some scraps of that laying around. The all-thread is basically just a guide. It will be anchored in the plate (at the required height) and a pipe sleeve will fit on the bottom. A nut and washer on the all-thread tightened down against that will do the pushing. As for the contact area on top of the piston, I might try bending some plate slightly to put an arch in it (so it matches the piston crown) and welding that to the bottom of the pipe sleeve.
 
Part of the face of one ring was sheared off......

stuck pistons 007.JPG

stuck pistons 013.JPG

stuck pistons 010.JPG
Yet another engine with what looks to me like evidence of hot wrist pins. Especially the RH .
 
5twins did you ever build your super duty piston pusher? Or did they just fall out after some more evaporust?
 
I was going to suggest a torch with heat around the pistons on the sleeve, As the metal expanded it might have cracked the rust seal, I did that on an H Farmall Tractor motor that was stuck.
 
Yes, I built the pusher. Details and pics are in the "Homemade Tools ...." thread, page 13, post #252. You saw it, in fact you commented. But that motor is still stuck, lol. I think it may be beyond hope, pretty much fused together. The cylinder and head are trash, was just hoping to salvage bottom end stuff. But I need to get the top off so the crank will come out. I may end up cutting the cylinders down the sides, lol.
 
Have you tried some dry ice on the top of the pistons? It might shrink the danged things enough to free them.
 
This thread started quite a while back, did those stuck pistons ever get free?
Coincidentally, a fellow CVMG member's XS650/Dneipr sidecar rig recently demonstrated that it will get you the 40 miles back home when running as a 325cc single but it burns lots of oil and don't like going faster than 30mph when doing it.
Turns out that peering down the leftside plug hole showed a neat circular hole in the piston crown "almost like it had been drilled" buddy sez.
Buddy tells the sad story to a friend who asks "wasn't that the piston that was seized when you got the bike and you finally got it free with patience and penetrating oil? Do you suppose the PO also tried to free it by shoving a bar down the plug hole and hammering on it? That's a great way to weaken a piston crown so it eventually fails."
 
Gary probably got his out, mine never freed up. I discovered a down side to the Evapo-Rust. Leave it in there more than a few days and besides turning all black, it turns into a tar-like substance. Makes a bigger mess than you started with, lol.
 
5t's piston pusher http://www.xs650.com/threads/homemade-and-unique-tools.37/page-13#post-448935


Yes mine came out. there's pics above, the engine with an overheated small end on one rod. It's a big deal to keep both pistons at the same height.
Usually one side is much worse than the other and it's easy to get to pushing on just the one piston. This can put high (dangerous?) stresses on rods and crank.
Keep in mind that as the pistons/crank reach the bottom on their normal travel the cylinders need to be blocked above the crankcase to finish the extraction.
Thinking on this now I might attempt to drill a hole or three through the pistons out near the edge to release pressure on the rings? (protect the CC from chips) avoid the wrist pin LOL
I still have a titled 70 with a seriously stuck motor in the shed. (one of these days, LOL) Working on a 400 husky years ago, a mouse set up housekeeping in the head, got in through the exhaust, I got the piston out with a rig similar to 5t's, would load up the piston as much I dared and leave it sit, a day later the piston moved enough to lower the pressure on it, tightened it up again, repeat, took about 10 days but got it out.
 
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