I am working on tearing down an 8BA flathead block. The pistons are stuck in the bores, and I've managed to move a few of them but the last two at the rear (#4 & 8) are really stuck. I'd like to be able to get the crank out at least. I have the rod cap bolts off, but the caps are also stuck. I have been using "PB Blaster" for about two weeks and beating on the underside of the piston wrist with long metal drifts and a 4lb sledge, but these two just haven't moved. I broke the piston top off of one. What other suggestions do you have to free these pistons? Can I use some heat? Should I carefully try to chisel the pistons apart (I'm afraid of hitting cylinder wall)? After hitting my left thumb twice with the sledge, I gave up for the day.
Diesel fuel, or Kroil... and LOTS of time! Some have had luck with lube, a 4X4 chunk, and a BFH. This topic came up awhile ago. Try to search for it, there was alot of good tips, including using a grease zerk in the spark plug hole, and a grease gun! Jay
This sounds nuts but we use a mixture of Coca Cola, and tranny fluid. It works for just about everything. The acid in the coke eats the corrosion away. The wife read about it years ago, and tried it on a 283 I bought cheap that had been real wet. I told her it wouldn't work but she did it anyway. A couple of days later, a mild swat and out those buggers came.
for really stuck pistons and rusted cylinder walls, i used to used a ball hone.you know the kind that look like a toilet bowl brush and fits in a drill. i would dip the ball hone in solvent and run it down the cylinders for a couple of seconds. that would take care of any rust on the cylinder wall and the solvent would get down into the rings and loosen things up. works quite well. just make sure you wear a face shield!!! diego
don.. First take everything apart...everything...your going to want to anyway..but first..what you might want to try is beat teh living hell out of it...don't worry about the pistons, if they break you can get them from someone on the hamb or ebay...that must be ed's block...you can also get a piece of 2x4 adn put on the piston from the head side, then WHAM...then from the back side...and WHAM...do that a bunch..might help..or start to drill the piston out.. tok?
If you want to drive 1 1/2 hour north I will give you a hand.All of your ideas have merrit, have used them all. Depends on the situation you have.Been there many times.
like already stated, get a spark plug and break the ceramic off and gut it. Weld in a grease zerk (pointing out of course) and screw it back into the plug hole. Start pumping grease in and the hydraulic action breaks it loose. IDK about the piston that you broke the top offa though, thatll need something else. Be careful not to knick the cylinder walls either. Briggs
I fought 2 of these stuck flatmotors for months! I used every conceivable trick in the book with zero results. I knew the cylinder walls were rusty so why was I so careful to try saving original STD pistons? They were gonna need a re-bore anyway...It made no sense. I turned the motor upside down on it's engine stand and like Tokyo says...removed everything I could and put the end of my long truck punch against the inside of the stuck pistons. I introduced mister 4 lb sledge to the punch [with malice] and in no time at all, I had those stuck pistons outta the way! Walked around the shop, picking up pieces of broken pistons to be deposited where they belonged...in the garbage. I sent Tokyo the good pistons I'd saved for his merc motor and saved the rods...the end.
One of the things I've done is get Zep brand hot tank solution and pore it in the cyl. It just eats the crap out of the piston and cleans the cyl wall at the same time. You won't re-use the pistons but it causes no stress to the block. The Wizzard
That's a brilliant idea....hot tank solution EATS aluminum, should melt those pistons right outta there! Is the Zep stuff in powder form?
Yes, I bought Ed's block. I have the heads off (hence, I'm not going to try the injection idea), main caps off, and all rod nuts off. Aside from the two stuck pistons, all the other rod caps are off. I've been using PB Blaster, which I've found to be about the best pentrating oil. I've had Kroil before and ina side-by-side test, didn't seem to be all that its reputation implied. I have been using a 10" steel punch and a 12" brass drift (both about .5 -- .75" dia) and a 4lbs sledge to beat on the underside of the wrist pin. Because the crankshaft is still in the way, clearance is tight. I can't get anything bigger in there. I went back tonight and poured a bottle of Coke into the bores. For the one with the broken piston, I used one of the free pistons, flipped around upside down, to plug the bore. Perhaps that will help a little. It certainly did fizz and all kinds of crap floated to the top. Yum! Where can I get ZEP tank cleaner? Sounds like a reasonable idea.
I had the same thing on my 59A's just remove the crank caps and pull the crank, then you can use the 4# and I used a 1/2 extension to break apart the pistons.
That's part of the problem, FastSporty, I can get the rods caps off either. I wanted to save the rods and caps, so I didn't think it was a good idea to try to beat them or pry them off. All of the other caps came off pretty easily once the piston started moving a bit. Is it OK to knock on the caps a bit to get them off?
Ok, if it's just two pistons left to take out you can put on a headgasket and head. Then you take a old sparkplug, knock out the ceramic isolator, install a grease fitting and pump up with a grease gun till the piston gives up. Don't forget to loosen the main caps and of course the valves must be closed. It's messy but you don't believe what power a simple grease gun has.
Is OzzyJuice parts cleaner the same stuff as ZEP? If so, I can score some of that stuff for you, Haring. Ed
The Jalopy Journal
