still can't break it free......

[Steve Minor]

I still can't free the piston free from the jug on my 1977 400...it's like I need a huge wheel puller or something....any opinions to the chance a machine shop could free it up with a hydralic press.....and do it without breaking cooling fins???

 

[Kip Kern]

Steve

I have used a large copper drift and a 2lb sledge hammer and driven out the piston.  Also have used a hydraulic press to push it out without hurting the fins.  Be willing to kiss the piston goodby.

 

[Steve Minor]

Thanks Kip...I don't mind losing the piston and rings so that's not a problem...as far as driving the piston out with a drift, it's still connected to the connecting rod....so I no room and I have to muscle the whole motor in each attempt I make...the only was I see to do it is press it out on a bench some way...or fab a special wheel puller...

 

[Mark Annan]

I have been reading about your piston struggle.  I have some questions for you.  Where in the stroke is the piston stuck? ( Top, bottom, some where in between).  Assuming that the piston is not at TDC or BDC and the crank rotates: How far off the case can you lift the cylinder before the connecting rod stops it?  Can you look into the ports to see if a ring is snagged? How much rust and corrosion is present?  If there is considerable rust and or corrosion in the cylinder and crank area worrying about the rod and crank may be a moot point (they may already be goners).  Measure the bore (or try to read the piston top stamp).  If the cylinder is already at or near it's max overbore it may not be savable.  If that is the case you can be less "graceful" in your attempts to dissassemble. If you haven't done so, get that engine out of the frame so you have more access.

Mark

 

[Steve Minor]

Mark, Thanks for your reply...I'll take your questions in order....(1) Piston is 1 1/4"-+ down the bore..don't know if it's on the upstroke or downstroke. (2) I can only get a knife blade between the bottom of the cylinder and the top of the cases but cylinder rocks slightly, telling me the wrist pin is free (3)Rings aren't visible from either ports. (4) there is no internal rust/crust in bore...only external crust. (5) it's the original bore. (6) motor is out of the frame and on the bench....I've removed all allen heads bolts,8 total...4 long studs, 4 short...I'm at my wits end. Any help is greatly appreciated!

Steve

 

[Paul Danik]

I will guarentee you that if I came to your house and was in my bare feet and lifted that engine by the cylinder, the bottom end would smash my toes.  Have you tried a little heat?  I would try and heat the cylinder with a little propane torch. I realize that the piston may expand faster than the cylinder, but the idea is to just get some movement to losssen it up.  I would direct the heat on the top section of the cylinder, right above the piston. I would even heat the piston through the intake and exhaust and even on the top.  Just try and get some expansion and contraction of the metal.  As always, be sure that no flamable fluids, ect are near or in the engine.
Paul

 

[Dante]

I mentioned "oil of wintergreen" in another one (of your threads). An "Old school" Harley guy in another forum SWEARS by it !

I've always had excellent success with PB powerblaster.

 

[Steve Minor]

I really appreciate all the advice and plan to act on all of it....Is there any way....any remote chance....that I missed a bolt? I've removed a total of 8 allen headed bolts....(4) 10mm long studs and (4) 6mm short bolts.....are there any others?

steve

 

[Rocket]

If you have the head off, the cylindar should be removable, no other nuts or bolts required.  The heat from a propane torch is a good idea.  don't give up, it will come apart.  Can you twist the cylindar at all?
Rocket

 

[Steve Minor]

Thanks Rocket....the cylinder will not turn at all.....none....nada....all it will do is rock slightly...I assume the wrist pin/connecting rod allows that...right now it's soaking in some of my wife's "oil of wintergreen"...(as I was advised earlier)...later I'll get out the small butane tank and give it a try....this will not beat me....

steve

 

[john durrill]

Steve you have probably already done this but just in case. turn the engine upside down and spray or squirt (what ever you are useing as a rust solvent) in the exhaust port. Then tilt the motor so it  can run around the cylinder. sounds like the rings are above the exhaust port (( thats why turning it upside down might help).
Heating and cooling should help too like the guys have suggested.
If you can get to the crank primary gear nut, you could try rocking it back and forth.
Dont excede the torque it is tightend with or it will loosen up,  or strip and be of no help. This might get it rocking in the cylinder and that will be a big help.
John D,



Edited by - JOHN DURRILL on 10/21/2001  1:36:44 PM

Edited by - JOHN DURRILL on 10/21/2001  1:38:02 PM

[Mark Annan]

Unless the piston is at TDC you should be able to lift the cylinder/stuck piston assembly off of the case to the height of the remaining stroke.  Make sense?  With all studs and bolts out the crank should rotate and the cylinder and piston should lift  the top of the stroke.  Put the transmission in neutral.  Will the counter shaft turn freely?   If so than the transmission most likely is not the problem.  If you cannot get the crank to rotate you probably have bad main or rod bearings.  Remove the ignition and clutch covers.  Use a strap wrench or similar tool to try to rotate the crank.  Once you get the crank to rotate lift the piston/cylinder to the top of the stroke to gain more access to the piston.

 

[Steve Minor]

Mark.....that makes sense and I really appreciate your help....I'll give your suggestion a try...I think I'm gaining a little bit on it, as the clearance between the botton of the cylinder and the top of the cases is increasing (it's about 3/8" now). The counter shaft/gear has always spun freely (in neutral)so I don't think it's the tranny....I believe with a little more sweat, I'll have her whipped..

 

[spowell]

I had the same problem about two weeks ago with an iron barrel 125. The engine had sat outside and water entered thru the carb port. I applied lots of Aero Kroil to the piston top, intake and exhaust ports then let it sit for a day. Banged on the piston for a few minutes and then applied more oil. Kept repeating this for about a week. Each time the piston would move down about 1/16" and I would add wooden spacers between the barrel and case as the cylinder worked it's way up(do not expect the piston to move down). The main bearings were very rusted and would only move about 10 degrees.

 

[Steve Minor]

Spowell.....that's for the hint....anybody that has read my posts knows the troubles I have had. The great members of POG have always offered advice and encouragement, which I appreciate. This WILL NOT BEAT ME! Looks like this weekend is turning out to be a garage weekend so hopefully I'll get it freed up. Then it's to the shop for a diagnosis and possible rebuild. On another note.....I'm thinking about taking my old pipe to a fab shop to see if they can use it as a pattern for a new one.

Any thoughts or opinions are welcome.