Tips/tricks for getting seriously stuck pistons out of the block

[Tim Ayers]

I'm in the process of tearing down one of the most stuck flatheads I've encountered so far. It's a Merc. 99A block, so I figure it's worth the effort if it turns out to be good. It's so stuck, I had to torch the rods just to get the crank out. No amount of Free All, Kroil or 50/50 mix made a dent into freeing things up.

My question is what are tricks/tips for getting these almost rust welded pistons out of the bores? I believe I read drilling a series of holes in the tops of them to get them to collapse inward. Last thing I want to do after going this far it to break up a bore by man handling things.

Any thoughts welcomed.

[deuce_roadster]

Take a hole saw and cut a large hole in the top of each piston. That usually releases enough tension you can drive them out by driving down on the wrist pin. An air hammer gives lots of non destructive blows to that area instead of using a BFH.

[Mart]

See if you can pop the heads off by knocking from underneath with a long rod. If they don't break with just moderate force use a method like described above. Once the head is gone the rest should move relatively easily. I have cracked a bore by heavy handed hammering on a stuck piston. The head had not been completely removed on that one. Get the crank out by fair means or foul and then attack the pistons one by one. I showed a couple of very heavily seized teardowns in some of my videos.

Mart.

[Kube]

Originally Posted by deuce_roadster

Take a hole saw and cut a large hole in the top of each piston. That usually releases enough tension you can drive them out by driving down on the wrist pin. An air hammer gives lots of non destructive blows to that area instead of using a BFH.

Winner, winner, chicken dinner!

After using up all of my patience in the distant past, I'd begun to do just as you describe right from the start.
Saves me a lot of frustration and gets the task accomplished quickly.
The pistons are trash regardless on the method of removal.

[Bored&Stroked]

Originally Posted by deuce_roadster

Take a hole saw and cut a large hole in the top of each piston. That usually releases enough tension you can drive them out by driving down on the wrist pin. An air hammer gives lots of non destructive blows to that area instead of using a BFH.

Makes the most sense to me! The last thing you want is too much application of the BFH - as that can split/ruin a bore.

[ActionYobbo]

Sponsored Links (Register now to hide all advertisements)

I have had a few tottaly stuck pistons and I figures out that if I popped the top off the stuck piston and got the first ring out I could hone the bore to remove the rust and lumps.(I had already honed the bores that were above the pistons). On the first motor I had to knock the tops of 5 pistons and ended up busting up 2 pistons to get the crank to turn. The other motor was 3 tops and the last motor was 2 tops and bust up 1 piston.
While doing this I had also released the rod caps that I could get a wrench to. This took some weight off the crank. Once I was able to remove the crank I could drive the pistons and rods out with a tool that I made from 2 pieces of 3/8x1 and a chunk of 1x1 for the handle. The tool looks like a tuning fork when its welded together. With the 3/8 bars hitting the piston at the wrist pin ether side of the rod and basically drive it out by the wrist pin but you have to clean the bores out with a hone or sandpaper first or the piston will just bust up.

[Viv W]

Take off what will unbolt, then chuck the whole block assembly into a large drum of water,( YES H2O,) leave it to soak for anything from 3 weeks to 3 months and every so often try tapping the pistons lightly.
I saw this article in an Australian hot rodder magazine and tried it. I have pulled apart complete motors, gearboxes and recently a rusted up back axle. It all came apart with patience.
A friend chucked a badly rusted Land rover series one motor into the Kafue river in Zambia, as he didn't believe me, 6 weeks later he took it out the river, took it apart, cleaned all the parts, honed the bores and with a set of new rings, bearing and gaskets it is now running again.
Believe me water penetrates and dissolves rust better than any oils.
Try it, IT WORKS.
Below are pictures of a Model A motor before and 3 weeks later, it was rusted solid, every part was salvaged and this pic of the block was taken just as it came apart, before we even cleaned it properly

282.jpg

281.jpg

283.jpg

292.jpg

[ActionYobbo]

Vinegar will do the same thing faster

[Viv W]

Vinegar even in mild form is acetic acid, given time it will eat anything aluminum, especially if there are copper gaskets in at the same time.

[26 lakes]

https://www.fordbarn.com/forum/showthread.php?t=61058

I have used this method for 20 years. It works. Make sure you use mineral spirits or starter fluid for a grill.

[tubman]

I have always been lucky enough to find unstuck engines. Right now, I am down to my last good block. At 81, I think that's all I need.

Kudos to you guys who bring these things back to life.

[Ggmac]

Water has worked for me also .

[1952henry]

If one didn’t need to get right after it, I wonder how Rust911 would work in a leveled. Lock, given time?

[highbeams]

Thank you! Viv W #7! Who would'a thunk!

[Ol' Ron]

i'M GLAD TO SEE YOUR ALL IN GOOD HANDS.
GRAMPS

[my4dv8]

I have an engine here out of a historically significant car , a PO had trouble getting the edelbrock heads off so put a 1/2” hole saw around some of the studs , ruined heads. Tried to drill the pistons out with a regular drill , went through the side of the bore in two cylinders. Yes there are morons out there.

[HambBurglar]

I had a similar problem taking the pistons out of a long stuck 59A block. I tried soaking in ATF, 50/50 mix, PB Blaster etc. I never tried removing the center of the piston tho. What eventually worked was using about a 12” piece of a landscape timber which just happened to fit almost perfectly in the bore and hitting the timber with a 10LB sledge. This was after great frustration and generally being ready to give up. Maybe not the first thing I would try but all 8 pistons came out and no damage to the bores. As my4dv8 stated, there are morons out there! Sometimes we get lucky.

[Preciousmetalsmotors]

Good info

[Eagle43]

I've had success by turning a block of wood the size of the piston, placing it above the piston and tapping the piston out with a big hammer. The force of the hammer blows is evenly distributed over the top of the piston and no damage is done to the piston or the cylinder walls. I've used this method on two engines and both are still running. I reused the pistons and only honed the cylinder walls. Of course I soaked them with ATF/acetone
for quite a while before this.

[Tim Ayers]

Originally Posted by Eagle43

I've had success by turning a block of wood the size of the piston, placing it above the piston and tapping the piston out with a big hammer. The force of the hammer blows is evenly distributed over the top of the piston and no damage is done to the piston or the cylinder walls. I've used this method on two engines and both are still running. I reused the pistons and only honed the cylinder walls. Of course I soaked them with ATF/acetone
for quite a while before this.

Eagle 43,

Funny, in with my flathead tools is a 2ft piece of an unturned wooden baseball bat. Happens to be just about the same size as the bore. I've used that for pistons that need some help getting going.

This pistons though are rust welded to the cylinder walls. This one is honestly the worst I've ever had. As you can see, I had to torch the rods to get the crank out.