Lnewqban

After scratching my head for a while, I believe I need some advice from you, gentlemen.

I have a nearly new OS LA 0.46.
The machine never saw Castor oil, and it was in repose for more than two years.

Now, the shaft does not turn by hand, not even one degree.
The thrust washer is loose.

I have been cooking the disassembled thing in pure car engine anti-freeze for three days with no result.

Before this, I put it in the oven at 200 degrees for 2 hours.

No part looks rusted or bended.

Any suggestions about what could I try next?

Thanks!

MinnFlyer

My Feedback: (4)

Fuel and a wrench

Villa

Put a prop on it so you can turn the shaft and have an idea how hard you are doing it. Spray it with something like silicone lubricant or a penetration fluid. Try to turn it one way and then the other. Do this a few times per day, keeping it well soaked. After about the third day, if it has not moved, increase the turning effort till it just barely moves. Take at least one week. Be patient. I think cooking it in the oven was bad.

Live Wire

A wood dowel the size of the piston and lightly tap on it as you try to turn it over.

sebo

I'd load that sucker down with WD40. I've used that method to loosen up a couple of engines.

Gray Beard

My Feedback: (-1)

Perhaps a pot of boiling water. It how I heat up an engine before I disassemble, it's even heat.

GREG DOE

The best penetrating oil is a home made mixture of automatic transmission fluid and acetone, mixed 50/50.
Heating the engine in the oven sounds good, but try a heat gun. First choice would be an industrial type
heat gun, which gets much hotter than our Monokote heat gun. The idea is that you want the outside
(aluminum crankcase) of the engine to expand as much as possible. Be careful since the home made
penetrating oil is flamable. If that doesn't work, send it to an engine specialist, or repair center. Greg

chopper man

Had an OS 25 that has sit for 25 years. Decided to put it back in operation. Yes it was frozen. I let it sit in some glow fuel for a day or so. It broke free and ran like a champ. Good luck.

chopper

DavidAgar

My Feedback: (108)

As Minn said, fuel and a wrench or fuel and a prop. Good Luck, Dave

TomBates

There is a penetrating oil on the market, available for a few years now, that's called Kroil. I've tried it on some badly rusted and frozen nuts and bolts with great sucess. You may want to give it a try. It's the best I've ever tried.

Lnewqban

Great advices; I appreciate each one of them.

I have returned it to the slow cooking in anti-freeze pot for one more day.
I will let it cool next, and try with a prop on the shaft.

Thank you all.[sm=thumbs_up.gif]

BillyGoat

Be sure to keep us posted on the results and what worked for you.

Will agree with TomBates, I'm a huge Kroil fan too. However think I found something better and a bit easier to find. It's call Feeze Off made by CRC. Used this a few times on the rebuild of a 40 year old vehicle. It has yet to fail me. [8D]

proptop

My Feedback: (8)

If you're doing the antifreeze bath again, try turning it over while it's still hot.
You're not doing yourself any favors by letting it cool off.
The antifreeze has a water pump lubricant in it as well...and that will help a bit.

Pull it out of the antifreeze bath, and quickly put a prop on it and try turning it over.

On the other hand, I've had good luck using Gummout (or equiv.) carb cleaner spray.

Unless there is some mechanical/physical damage inside, (something jammed between the piston and sleeve, or a burr, etc. ) you should be able to break it free without much difficulty.

jaka

Hi!
It's easy!
If the engine is ok (No bent connecting rod or sand in the crankshaft) ! Just heat it with a heat gun and turn it over with a prop on!
No WD-40 or Aceton will ever free it!!!

As you don't have any ball bearings that can rust there is only the crankshaft left that can rust and it isn't likely that it has rusted, more likely it is stuck because of old Castor oil that has hardened.

eagle1945

let it stand in acitone for a day and then oil with light 3 in 1 oil. put on prop and rotate back and forth till loose.

Lnewqban

Just reporting back:

Yesterday, I cranked the heat up for the last hour of the anti-freeze bath.

The pictures show that the blue color is gone in many spots.
The plastic lever of the carburetor throttle just disintegrated.
A lot of green gel formed inside the engine.

Before the engine cooled down, I installed an 11” propeller, and tried to turn the shaft gently and back and forth.
Only the cylinder sleeve slid up from the crankcase, the piston and sleeve remained solidly attached.

Next, I washed the whole thing with plenty of water to eliminate all the green gel.
I dried it up with the heat gun.
Then, I sprayed it with carburetor cleaner abundantly and put it to rest inside a closed zip bag.

Two hours later, all parts were sliding properly, and they were lubricated with 3 in 1 oil.

Now, I would like to continue on to a full disassembly and deeper cleaning of the main crankshaft bushing.
However, for a reason that I don’t know, I cannot remove the connecting rod from the crankshaft pin.

The steel cylinder sleeve is now removed and the piston/connecting rod assembly can move freely inside the aluminum bore, but the rod’s bronze bushing cannot be slid completely out of the pin for any position of the crankshaft.

I also have problems with the head of the bolts that hold the muffler and the carburetor as they keep slipping off the screwdriver.
That is the reason I left the carburetor and the muffler take the antifreeze bath, which destroyed the plastic throttle arm.
I have checked Tower Hobbies, and that plastic arm is not available.

What am I doing wrong here?

Thanks for the additional input.

TFF

Place some valve lapping compound on the tip of your screwdriver; it will help it grip if the screws are not to far gone. I believe the Japanese use screws that are not true phillips but slight different standard; I bet the screwdriver bottoms out before the sides can fully engage. Sometimes filing the end of the screwdriver down a hair can help.

MinnFlyer

My Feedback: (4)

When screws do that, I cut a slot in the head with a Dremel and use a straight-slot screwdriver

Bax

My Feedback: (11)

The Japanese cross-point screwdrivers use JIS (Japanese Industrial Standard) shaping. Basically, you can use a Craftsman #2 crosspoint screwdriver for the carb retainer screws. Many times, for smaller screws, we'll grind the point off of the American Standard crosspoint or Phillips screwdriver.

The throttle arm is most certainly available. Likely the phone rep didn't know how to find it. Here are the stock numbers and list prices of the parts you asked about:

OSMG9027 21281410 THROTTLE LEVER 40D US$4.49

These parts can be ordered through any hobby retailer who sells O.S. Max engines and accessories.

When the cylinder liner is removed, you should be able to slide the connecting rod aftward to get it off the crank. Make sure the crank is pushed as far forward as possible. If the rod still won't come off, it's likely that it's seized to the wrist pin inside the piston, and that won't allow it to move aft far enough to come off of the crankpin. In such a case, more soaking in fuel may help. If all else fails, you may need to actually cut the rod. We do that by drilling holes that are very close together, and then clipping the small metal bridges between the holes.

ChuckW

I bought a set of these: http://centralhobbies.com/Tools/jis.html

One of the best $20 purchases I have ever made. They fit all sorts of JIS screws found everywhere on engines and airplanes perfectly. I haven't had nearly as many damaged screw heads as I used to.

GREG DOE

Bill Baxter is dead on about the conrod being seized to the wrist pin inside the piston. I'm not familar with
the LA engines, but some engine designs require that the shaft be rotated to the top dead center
position to remove the connecting rod from the crank pin. A pair of needle nose pliers or hemostats will help, after more soaking and heat. Greg

proptop

My Feedback: (8)

I've encountered a few extremely stubborn engines like this...

The antifreeze and carb cleaner should have gotten rid of most of the varnish on the wrist pin, if there was any.
If you have rust on it...and I would say that's more likely in your case because you said that Castor was not used in the fuel.

I would use some PB Blaster, or Kroil, etc. and soak the wrist pin / rod area over night, then very carefully heat the top of the piston and rod w/ a propane torch (using a low flame ) Heat until you have just a wisp of smoke comming off.

You can try and lever the rod back on the wrist pin with an allen wrench...put the crank at bottom dead center...put a little masking tape on the short end to prevent nicks/gouges in the alum. rod, and wiggle/jiggle the allen wrench in through the backplate opening to try and pry the rod back on the pin.

Another way is to wrap a piece of heavy string around the rod so you can pull on it and hopefully pull the top end of the rod back.

Using care to not apply excessive force, I've gotten some very stubborn engines apart without ever bending a rod or having to cut one.

Lnewqban

Once again, thank you all very much; all great tips!

I will work on that piston pin next.
If that connecting rod was assembled in the factory, I will be able to pull it apart.

jaka

Hi!
All you have to do to loosen old gunk in your engine ... is use your heat gun,remove, clean and oil !!!
Then to loosen screws with worn heads ..just use the Dremel cutting wheel and cut a slot in the head and use an ordinary flat screw driver

Lnewqban

I have just tried everything, and this is as far as I have progressed:

The pin slides in the piston, but the rod does not slides on the pin at all.
The pin is not rusted, and I have soaked it in carb cleaner and fine oil for some hours.
There is nothing (clip, Teflon, etc.) keeping the pin from frictioning the cylinder wall.
That made me think that the pin may be designed to be free to rotate on the eyes of the piston and not on the connecting rod; although I may be wrong.

Regardless of protecting the rod with heavy tape, my pliers have made some dents on the aluminum.
I don't know how important that is for aluminum; I do know that it is bad for steel rods in bigger motors because they could initiate cracks.

I am at the point of leaving the thing alone, lubricate it well, and re-assembly and fire it up.
I believe that I am becoming too obsessive with this cleaning. [sm=71_71.gif]

More advices are welcome.
Thanks for your patience!