flathead tear down progress

51merc

51merc

Junior Member
still haven't been able to get it to rotate, even after PB Blasting the cylinders; went ahead and dropped the pan(appears to be a ford crank).gonna remove the oil pump and was considering going ahead and removing the crankshaft; if i remove the bottom part of the connecting rod bearing clamps, and the three main bearing caps from the crank itself, shouldn't the crank drop out? i'm hoping this might enable me to get those pistons to move a little bit.
thanks in advance
 
probably should've just kept the original thread going as to not confuse.
jack, i've already got the valve assemblies out, as well as the cam.
 
You could try and remove the cam gear and see if it will rotate, that way you will know if it is stuck valves or pistons. I had one engine that was stuck so bad I had to break the pistons into little pieces to get them out.
 
Just finished a 50 teardown. Stuck pistons are a real pain in the butt.

I tried to take out the crankshaft so I could get a better hammer swing to the pistons.

The crank will not come out with just the rod caps and main caps removed. The angle of the cylinders puts the rods close together so there is not room to get the crank out without sliding the pistons and rod up. If they are stuck you can't move them.

I finally got several long pieces of old oak lumber and after soaking for more than a month was able to beat the pistons up enough to get the crank out.

Like the frog said "DON'T EVER GIVE UP".
bill
 
I'd leave the main caps on and remove the pistons. You can't get the crank out without removing the rods and pistons. I've used a hole saw to cut the heads off the pistons. Then break them out.
 
Removing the cam gear is a good idea.
Try 50/50 mix for several days.
Crank will not come out with rods in place.
Last but not least, "Slow down, you'll get done sooner"
Keep the rod caps together.
 
took the rod caps off, along with the main caps, only had one piston stuck so bad it wouldn't come out, even with a little coaxing with the ole BFH. gonna soak that one for a while. crank came right on out, after turning it a bit to get the rods to clear the cylinders.
thanks guys, i'm going to bed now....
 
Mr 42 said:
This is how i did one of mine. Without breaking the pistons.

http://www.brandow.eu//album/59abII/index.html
Click to expand...

Good reference here. The comment about using kerosene is a good tip for all. It's relatively cheap and it does an excellent job. Adding a little motor oil to the kerosene leaves a lubricating residue behind. Like an old cook, I tend to do things to taste rather than an exact science, but I would guess that I use about one part oil to nine parts kerosene.
 
When i used my big Cresentwrench and BFH it put all force on the piston wrist pin instead of the piston itself.

And i think ist better to add the kerosene from the backside/underside of the piston, Or if you have patience from both sides.
 
I did a similar job recently on a scrap 21 stud motor.
I had stuck pistons.
I got the crank out by wiggling it past the rods.
I then got a long punch up against the base of the piston crown, where it's thick and with a couple of good hard knocks, broke the heads clean off the pistons. Once the head was gone, the rod and remnants of the pistons came out quite easily.

Didn't take a pic during the process, but here are the rods and remnants after removal.

21stud05.jpg



Mart.
 
Mart, that's one ugly pix you got there. I don't think I could bring myself to do it even on a "scrap motor". I'd rather do the old trick of letting the motor rest on a breaker bar on the crank nut, keep lubing the cylinders every few days until you see the block starting to move down from the gravitational pull of the world. Might take a week or maybe even a month. But eventually gravity will do its thing without having to resort to such violence. 8^)

Jack E/NJ
 
If there's a build up of heavy rust on the top of the pistons there's no way they will force past the rust , forget the Kero /oil ,The rust needs to be removed ,The best thing for that is soak it in Vinegar for at least two weeks,
 
As an amateur, I used ford barn for advice. The guys recommended every substance under the sun to try and free up a stuck piston. Nothing worked!!! Not even the lumber or hitting the head of the piston...nothing. The ONLY way to get a really stuck head out is to collapse the center of the piston head. Be careful not to hit the rod, but DRILL 4 to 5 holes around the outside of the head, dont hit the wall of the cylinder. Use a bit just smaller than your pinky. Then hit the piston right in the middle. The piston middle collapses the walls of the piston free from the cylinder wall. I wasted 1 month trying to soak it. Took me 15 mins to drill and get loose. Chances are if the piston is stuck, the motor needs some cleaning and probably new pistons. Good luck.
 
For the real bad rusted in pistons I cut the rods off with a torch or sawa-all. Then with a 3" hole saw cut the top of the piston off. Now using the saws-all cut some slots in the skirt of the piston. Now you can take a chisel and break the piston up. This usually gouges up the cylinder pretty bad, but boring to 3 5/16 cleans this up. The last stuck piston I had the 50/50 Acetone/ATF worked fine after 3 days.
 
I'd hate to cut up a useable 21A rod. Otherwise a good idea. A glaze-breaker cylinder hone will clean rust off cylinder wall above the piston.
 
i got a couple modelt pistons out using a h puller.soak it down with pb blaster and put a piece of steel on top of piston.mount h puller on two head bolt holes and push piston down.if it don`t move we put pressure on it and let it sit going back every now and then and tighten the puller.eventually they loosen enough to get them out.
 
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