Stuck flathead been sittin' long time and is stuck.

C

Crestliner2

Junior Member
I, have a Merc flathead that is stuck after sitting for a long time. Engine was running fine when I parked it. Any idea's of how to get it unstuck without having to pull it apart or doing damage to it?. I am not sure what may have caused the problem.
 
usually what sticks is the valve stems, rings if it got water in it. use half atf and acetone-spray in to the spark plug holes-a good fog in the cylinder, pour some down the carb throat. let it sit for a few days
 
Yes, Time is on our side. I soaked an engine for 6 months after it sat for 30 years and it finally freed up and ran fine!
 
thanks for the reply guys I have already pulled the plugs and sprayed a fog of PB blaster down the plug holes I will try the ATF as well, and also left the spark plugs loose to allow the compression to escape. should I just keep trying by hand to free it or can I give it a slight tug while its in gear?
 
I would do it only by hand. You have more feel and are less likely to damage something. As it is soaking, I have used a wrench or socket to occasionally apply light pressure on the front pulley nut until the engine frees up.
 
Also, I've always worked them back and forth once it starts to move a little bit. Another option is to pull the heads - which isn't a huge job, then you can get an idea pretty quickly as to what the issue is.
 
That mixture works I sprayed the cycllinders on and off for couple months and rocked the can back and fourth in third gear and one day the car rolled . At first I thought it popped out of gear but it Free up . I hand rotated the motor offen then compression tested ...
Watch when she fires smoke out and toasted acorns .
 
Another trick I've used is to put a breaker bar on a socket, put it on the crankshaft bolt, and then put a bottle jack under the end of the breaker bar and jack it up a few inches, so there is a constant pressure on the crankshaft. How much to jack it up is more of an art than scence. Use this in conjunction with your favorite "witches brew" in the cylinders.
 
If it frees up and rolls around until it hits a hard spot be real careful as this is a valve that is stuck closed. If you push too hard the lifter will break the camshaft sure as shinola. The key is once you get it to move just take the heads off and clean everything up, Drop the oil pan and scoop the gunk out , squirt some fresh oil on all the bearings and you are ready to see how it runs
 
alright I think I will try the bottle jack torture method and see what I come up with. Thanks again. This site is cool, lots of knowledge out there keep up the good work!!
 
Since tricks were mentioned, I once freed up an engine by draining the water out and re filling it with HOT water. I heated buckets up on the stove. Wasn't to popular with others who normally used the kitchen.....
 
If you have the parts and access to a welder you can make one of these. It allows you to use the leverage of the outside diameter of the flywheel, just like the starter does. I like it better than using the bottom pulley bolt on the crank. You still have to be very patient and go easy. Use alot of moose-piss. Mark
 

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This subject has come up recently and I just got this email thought it pretty interesting."Machinist's Workshop" recently

published information on various penetrating oils. The
magazine reports they tested these products for "break out
"torque" on rusted nuts and bolts. A subjective test was made of popular penetrating oils, with
the unit of merit being the torque required to remove the nut from a
"scientifically rusted" bolt.
Average
torque load to loosen nut:
No Oil used ........................516 foot pounds
WD-40
..................... ........238 foot pounds
PB
Blaster .........................214 foot pounds
Liquid
Wrench ......................127 foot pounds
Kano
Kroil .........................106 foot pounds
ATF/Acetone mix..................... 53 foot pounds

The
ATF/Acetone mix is a "home brew" mix of 50/50 automatic transmission fluid and acetone. Note this "home brew" released bolts better than any commercial product in this
one particular test. Our local machinist group mixed up a batch, and we all now use
it with equally good results. Note also that Liquid Wrench is almost as
good as Kroil for 20% of the price.
ATF/Acetone mix is best, but you can also use ATF and lacquer thinner in a 50/50 mix. ATF = Any
type of Automatic Transmission Fluid
 
Ive used the atf acetone mix to free up a motor with no heads on it.

One thing i noticed is that the acetone evaporated in about 12 hours so i dont know how much better the mix is compared to straight atf.
 
One technique that has been used to free stuck pistons is to remove the heads and then pack sawdust into the cylinders. Soak the sawdust with diesel fuel and oil until it is saturated. Then light it on fire. Suggest this is done outdoors with extinguishers nearby.
The oil mixture burns and expands the cylinder walls slightly and allows the oil to seep downwards. Once heated and oil soaked the engine usually frees up.
I was told of this method about 25 years ago at the Grand Rapids MN swap meet. I have not had any reason to try it but pass it on for what its worth.
If valves are stuck use the methods described above.
 
If someone tries the sawdust and fire method, remember the stuck engine should be out of the vehicle to avoid destruction of the vehicle.
 
To follow on from jakeford, a bit of rag will do. You do not need a lot of diesel. the fire is small and does not go well because it tends to be limited by the( lack of)air flow. The idea is to have it burn for quite a long time, thereby generating some heat in the metal.
I tried it, but the engine was one that had been partly stripped, and was abandoned to a paddock. The pistons were white with years of oxidation. I drove them out with a hammer and bits of wood. I think the fires helped.
 
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