I finally got the '51 Mercury M-3 home. I've already started to clean it up. I hope to have pictures for you guys soon. Have any tips to get the flatty going after I get it unstuck.

 

Put it in a wheelbarrow and push it down a hill? Sorry Ed

 

Hardy har har. Anyways any help is appreciated.

 

Is the engine froze up and have you made any serious attempts to unstick it? Ed

 

Flat motors are incredible and will run when others won't. If you get it unstuck - liberal amounts of ATF or diesel in the cylinders and valve train, etc and it will turn over by hand......drain all the solvents, fill crank case with fresh oil and turn it over again to get the bearings lubed. Fresh plugs, make sure you have fire, gas thru the carb and it should run.

 

I filled it up with diesel yesterday night and when I get home I'm gonna see if I can turn the crank. It ran supposidly 2 years ago. I haven't got my carb kit, points and filter in the mail yet.

 

I'd buy Marvel Mystery Oil and inject it into the spark plug holes, and douche the intake with MMO to try to soak the valve guides. Carl will probably offer some real experienced advice soon, but it will probably include information about the tendency of valves to stick open on flatheads. The good news is that they won't hit the pistons if they stick open.

Ya know, that cylinder head is pretty easy to remove. You might want to pop it off, spray PB Blaster on the edges of the pistons to try to soak the rings, spray more on the valve guides, and then turn it over by hand to see if anything is sticking open.

 

I'd prefer to leave the heads on (I'm to cheap to buy new head gaskets). I've sprayed a prenetrant in the cylinders through the spark plug holes. After school I'm gonna try giving the truck a little tug in gear to see if that will losen the engine so I can turn the crank. I've removed the gen, fan and shroud so I can fit my 3/4 rachet on the crank. It doesn't really want to move. I already striped one bolt on the crank. It does have a fram oil filter in it.... Have any of you guys noticed bad rust above the rear window? My other two cabs don't have this. The seat mounts on the floor are cracked right through in the front. I'm gonna need a big washer to overcome this.

 

I gave the truck a yank. Both rear wheels turned and truck was in gear. Is it possible for the clutch to slip because the engine didn't move? I'm ready to strangle the guy that stole the carb, fuel pump. I finally figured out why my brakes didn't work because the bugger stole the brake light switch and cut the wiring. I stuck the one I have in but I don't have any wires to connect this. It is like a $5 thing. ARRRRRGGGGHHH. I'm also out brake fluid in the cylinder.

 

Possible that the clutch slipped. Yes, but not likely.

I've heard of people putting a wrench on the bolt of a crankshaft, jacking a jack to put pressure on the wrench, and leaving it overnight.

I wonder if it would work to fit an air hose to a spark plug hole and attach a compressor. 175 psi might be able to gently rotate an otherwise stuck engine.

 

I tried something to that extent but not with a jack. Our air compressor only goes up to 120 psi but I don't want to crack anything or blow my head gasket.

 

I wouldgo back to soaking the cylinders large amounts of marvel mystery oil in each one th stuff will free up anything but let it sit for a few days and let the oil do its job. dont rush it thats the key ( ive freed up motors that sat for 15 years with thi stuff)

 

I don't know if you can get that mystery oil in canada because I have never seen it. I have it full of diesel and I just sprayed some WD-40 in. I think the front 3 or 4 cyls are stuck. The other ones empty out the diesel pretty fast.

 

I've never had the experience of freeing a stuck engine so I may be more full of stupid questions than help. However, I am courious just in case my wife lets me buy another truck some day.

Seems to me that dumping stuff down the spark plug holes of an OHV engine would work well but with a flathead you would get a lot of stuff into the intake and exhaust ports where those valves are open. This might be good because the valves need to be freed up too. And you probably won't collect too much in the intake ports. But I would think you could end up with a lot of stuff in the exhaust system. Probably it would just make a good smoke show if you got it running. Flames out the tail pipe might be cool. I think I would disconnect the exhaust pipes to make sure nothing is coming through the manifolds.

I liked the idea of using air pressure. Shouldn't hurt anything since the cylinders must see well over 200psi when the engine is running. However, I did some figurin and I don't think you could develop but about 200 ft-lbs torque that way. You're probably doing better with a whench.

I think the engine in my truck might have been frozen at one time and just before I bought it somebody unstuck it by rolling it down hill and popping the clutch in high gear. Seemed to run pretty good when I bought it. After a couple hundred miles I lost compression. When I took the engine apart I found the top ring broken in every cylinder.

 

Yep dmptrkr that what happens when you rush trying to free a stuck engine they rust the most around the top rings so it is best to le the oil sit in the cylinders for a few days and the apply a little pressure with a breaker bar on the crankshaft bolt and if it seems to hard to move ( shouldnt take that much preasue with a long 1/2 inch breaker bar ) then put some more oil in the cylinder and let it sit. and yes it does smoke when it starts but the oil burns off and it isnt a thick oil its more like a diesel type consistancy but i has something in it that really works.
When i was a kid i used to pick up old lawnmowers from the dump that people had thrown away cause they seized them up, id pull the head off and fill the cylinder with mystery oil let it sit over night and the next day put the head back on and you could spin them over just like a new engine.
When i put my camaro away in 1989 i put mystery oil in the cylinders and it sat ouside until last month when i traded it , motor started right up with no problems. ( i dont mean to sound like an advertisement for marvel mystery oil i just know it is a very good product!!!)