Been trying to unstick my 53 Merc EAC for about a year now. It's been soaking in PB & Kroil all this time. Last weekend I tried the propane heat method but still couldn't get any wicking into the rings. I flipped it over last night and started to remove the rod caps & main bearings. They all came off easily except for two rod caps that I can't geet a wrench on because of the location in the block. The journals look good and are standard, not cut so I am happy about that. It is a 4" crank. One of the pistons & the one with the only rust in the cylinder has a cracked piston. I pulled the camshft gear so I know it's not the valves holding it up. I have been pounding on this thing now for a couple of hours and it won't budge. The 7 other cylinders look good and are not rusted but I can't break the rings free from any of them as well. Outside of a bigger hammer I am really at a loss. I don't want to do damage to the cylinder walls as they are standard bore and the one with rust looks like it would clean up nicely at 30 over. I have a 1/2 " breaker bar on it with about 4' of pipe but that ain't moving it either. Any help will be appreciated.
try to get the last 2 rod caps off there are always 2 that are hard to get so grind down a socket or try a long box end but keep trying to get the crank out. i use a 2ft long 1/2 inch bar to beat on the backside of pistons some times you can pop the crown and rings out also on the wrist pin boss. it sometimes wrecks the rod but they are easily replaced. all the lube oil and heat in the world wont touch a rusted flatty! good luck
Sheettt !! Don't worry about it cleaning at .030 .You can bore 99.99% of flatties .125 no sweat. Rods are not hard to get ,if you have to torch off the odd 2.
.A mix of Diesel and Kerosene gets into places other fluids can't plus it's cheaply made. The diesel never stops seeping and the kerosene is thin which helps draw the diesel in. JMHO but Miracle or 'mysterious' Oils are all about advertising and hipe and less about penetrating. Plus as an added bonus you pay out a lot of good money for only a few measely ounces of pretty different smelling stuff with the neatest looking shinny label on the can and a pleasently mysterious (unknown name since 1884!). Truth is you can make an Ultimately Far superior penetrate with Just a 50/50 mix of Diesel and Kerosene...... Even then, not all piston will move so you maybe Forced To sacrifice a piston or 2 using a hardwood board and big hammer. Removing the piston in pieces allows you to get to seized rings. You will be replacing pistons anyway so use the hardwood boards and a Good Heavy hammer to pound the -Worst of the Worst- stuck piston(s) to pieces then you can access the the stuck rings.... Good Luck .
A couple trick I've used in the past on bigger old engines. 1) on a huge cat that was froze up we had a 3/4" plate and bolted it on inplace of the head and then took and air grease gun and pumped the cylinder full of grease till the pressure was so great that it pushed the piston out the bottom of the block. 2) another thing you can to is to put dry ice on top of your piston and let it sit for a while put some more dry ice on the piston and try to turn it over again with your 4' bar. Hopefully the block isn't cracked. Good luck!
Jet Mek, Took your advice and used a 1/2 rod I had laying around. It sure screws up the pistons and probably the rods but I got 4 of them free. Can't drive them all the way out yet as the rods are hung up on either the crank or the cylinder wall, but it is progress. I have one more nut to take off the rod bearing. Grinding down an old box wrench helped on the first one but I still can't get it on this one. Maybe a little more grinding. I really appreciate all your comments on this as I have asked before and most guys direct you to the off the shelf lubricants that I am now convinceda re a waste of money on a project like this. Probably good on loosening fasteners but not pistons. Thanks again.
One more piston to go & that is the one with the buried nut on the rod cap. It was starting to get rounded so I stopped. Gonna buy a six point box (can't believe I didn't own one, had all the other sizes) tomorrow and try that. If that doesn't work then I guess I fire up the torch (which I really, really don't want to do) & cut it off. Thanks to all of you for your help.
I have a 427 sideoiler that had a stuck piston I beat it with a mall and a piece of shaft and it wouldn't budge. I ended up drilling several large holes in it and finally got the piston to crack and tapped it out. It had forged pistons, so the flathead should be easier to break free.
Get someone to help juggle the iron and remove main caps...then you can lift crank and flop the unreachable rod in another direction.
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