Froze up Pistons

[special88]

How can I go about unlocking froze pistons. I have a water problem that rusted the pistons. It is a '87 Johnson 88HP SPL.

 

[Joe Reeves]

Re: Froze up Pistons

Remove the cylinder heads. Have the engine tilted to an extreme whereas the pistons face as straight upwards as possible.<br /><br />Apply penatrating oil, WD40 or some such lubricant to the top edges of the pistons. Using a piece of 2x4 or 2x2 and a good size hammer, tap the pistons downwards and hope for the best.<br /><br />However..... if by a water problem, you're saying that water has entered the crankcase somehow, your problem may be somewhat excessive and not limited to the pistons, such as a rusted crankshaft, connecting rods, bearings, etc etc.

 

[Chinewalker]

Re: Froze up Pistons

Tear it down. Any time you've got rusted parts, a teardown is in order, as it's usually more than just what you can see. At the very least, you can inspect the other parts and replace the one or two items that are stuck. I find that a bench press works wonders for punching out stuck pistons - usually without damaging anything in the process....<br /><br />You have nothing to lose by tearing it down, but a lot to lose if you get it freed up and try to run it without a teardown...<br /><br />- Scott

 

[Silvertip]

Re: Froze up Pistons

I would suggest a gentler method the wood block and hammering on the piston. Ring and ring land breakage are very possible. Soak each cylinder thoroughly with any good penetrant such as SeaFoam Deep Creep. Let the engine sit for a couple of days. Using a breaker bar and socket on the flywheel nut, GENTLY try to rotate the flywheel back and forth. If it doesn't move at all, soak again and wait. Repeat this process until you feel a very slight amount of movement. Rock the flywheel within the limits of that movement and continually soak each cylinder. You will eventually get it to turn more and more and it will come loose without damage. Of course there is always the possibility that the cylinders are pitted and rings damaged from the rust -- it all depends on how long it was locked up and what you want to do next. As others have pointed out, you may also have crank and bearing problems as well so even though you do get it loose, running it may cause its total destruction anyway.

 

[wayne h]

Re: Froze up Pistons

PB BLASTER in the spark plug holes have the engine tilted and let it soak for a few days every day try to turn the flywheel back and forth with your HAND or strap wrench dont use the starter for this because u will break a ring. if it moves alittle and stops spray it up some more and leave it over night it might take a few days to get it to turn over. remember to take your time and keep spraying the pb blaster in the cylinder. dont be cheap with it eather spray her up good and let her soak. i have unstuck many motors like this. i would not use a breaker bar on the flywheel nut only because i have seen the crank strip. that is a torqued nut and tapered shaft. also wd-40 is not a rust buster. i always used pb blaster it works great.

 

[beau123]

Re: Froze up Pistons

Kroil is about the best stuff there is for getting rusted things apart.

 

[Solittle]

Re: Froze up Pistons

Marvel Mystery oil is a great alternative.