how to unseize RUSTED pistons

[superwesman]

I've got two pistons in a parts engine (thanks dan!) that are totally
rusted and stuck to the cylinders - I really want to get at the cam
chain tensioner parts and I don't care about the pistons or the
cylinders - how can I free the pistons? one is all the way up, one is
all the way down - I've read some tips online about soaking it in an
oil/diesel mixture, soaking it with PB blaster or shooting it with a
handgun (seriously). I've got liquid wrench soaking into the piston
that is down, but I won't have the same luxury for the one that is
up....

oh - and I've tried hitting the pistons with a hammer and with a
rubber mallet - I've also tried hitting the cylinder head with the
rubber mallet with no lucks so far...

here are some photos:

http://dicky-pickles.org/d/images/cl350-parts-engine-left-pistonjpg

http://dicky-pickles.org/d/images/cl350-parts-engine-right-pistonjpg



-w

[Bobby Cleveland]

Ditch the mallet and use a hammer.  :-)

http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/album289/CB350IceBike/engine_build/100_7952.jpg.html

http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/album289/CB350IceBike/engine_build/100_7950.jpg.html

[d...@gurovich.com]

Depending upon where the piston actually is, whacking it with a hammer may have no effect if it's at or near TDC since there is no leverage on the crankshaft.  The bearings are getting mashed around and absorbing all the energy of the blows.

Marvelous Mystery Oil.  Soak for a week, check it daily to keep it wet -- then TURN the crank at the end of the week.  Once it starts to move you can start whacking it as much as you want.

Danilo

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[jds-MothSteward]

On Jan 23, 12:19 pm, superwesman <superwes...@gmail.com> wrote:
> I've got liquid wrench soaking into the piston
> that is down, but I won't have the same luxury for the one that is
> up....

Hey Wes? Why cannot you throw some oil on top of the up piston
through the spark plug hole?

That is, if the head is off, you can pop it back on, then use the
upper chamber to hold oil against that piston. Else, an oily rag may
help wick some oil into the small gaps.

This link may be helpful. I like his "online course" as a practical
handbook.
http://www.dansmc.com/stuck_engine.htm

Keep us posted,
John

[TEAM...@aol.com]

It could be that there is more at play than the pistons. Actually, most pistons are alloy so it's likely not the piston that's rusted to the cylinder but the rings that are rusted to a cylinder that likely has rust as well.

Soaking the rings with oil by pouring it from the top is usually the best course of action. PB and Liquid wrench might work but I'd get some Strong Arm or better yet, Kroil. They work best at saturating rust and getting it to free up. If you can get it down below the crown of the up piston to wet the ring area is all you would need there.

 There is also the possibility that it's not the piston rings that are your main problem. Could be the crankshaft or the crank bearings so if you can access the bearings from the side, soak them up too.

Good luck. 

 

 

 

 

 

In a message dated 1/23/2011 12:19:18 P.M. Central Standard Time, super...@gmail.com writes:

I've got two pistons in a parts engine (thanks dan!) that are totally
rusted and stuck to the cylinders - I really want to get at the cam
chain tensioner parts and I don't care about the pistons or the
cylinders - how can I free the pistons?  one is all the way up, one is
all the way down - I've read some tips online about soaking it in an
oil/diesel mixture, soaking it with PB blaster or shooting it with a

handgun (seriously).  I've got liquid wrench soaking into the piston

that is down, but I won't have the same luxury for the one that is
up....

oh - and I've tried hitting the pistons with a hammer and with a
rubber mallet - I've also tried hitting the cylinder head with the
rubber mallet with no lucks so far...

here are some photos:

http://dicky-pickles.org/d/images/cl350-parts-engine-left-pistonjpg

http://dicky-pickles.org/d/images/cl350-parts-engine-right-pistonjpg



-w

[Jeff Stephens]

Yes, with the motor being stuck at TDC (worst possible scenario) you will have to try and get the crank to turn some while whacking at the pistons. It also would help to get the cylinder jug nice and hot with a map gas torch or something hotter.

 

BTW; remember the center of the piston is the weakest; to avoid just popping a hole threw it, use a wide O.D. drift or hit it off center. Just don’t hit it too close to the outside edge because then you’ll collapse the ring grooves or flair the top.

 

   Godffery

 

---

[norcati49]

The April/May 2007 edition of Machinist's Workshop did a test of
penetrating oils where they measured the force required to loosen
rusty test devices after 8 hours of soaking with the various oils.
Penetrating oil . Average load .. Price per fluid ounce
None ................. 516 pounds .
WD-40 .............. 238 pounds .. $0.25
PB Blaster ......... 214 pounds .. $0.35
Liquid Wrench ... 127 pounds .. $0.21
Kano Kroil ........ 106 pounds .. $0.75
ATF-Acetone mix.. 53 pounds .. $0.10

The ATF-Acetone mix was a 50/50 mix (1 to 1 ratio) and seems to be
worth a try if you're still "stuck" for a solution. Might even save
the pistons. I have a Ducati friend who swears it is the best.
Terry

On Jan 23, 12:19 pm, superwesman <superwes...@gmail.com> wrote: