Freeing up frozen engine

I just bought a 1970 Norton Roadster. Engine froze but got bike for a great price. Any suggestions about how to free up the engine? Thanks

Remove the engine from the frame and pull the head. Soak the pistons with your favorite concoction. Kroil, ATF/Acetone, kerosene, etc. After several days, try driving the pistons down the bore with a hefty block of wood and moderate hammer taps. If all else fails and the pistons are not at TDC, remove the cylinder nuts and split the cases, and remove the rods from the crank. Now you can take the cylinders to a press and push the pistons out. This will destroy the pistons, but the chance of saving them is slim anyway. Protect the rods and support the cylinder by the base. Patience and perseverance is needed here. I have only needed to use the press method once.

Take the head off first thing and if still frozen drop the rest of the motor into a drum of diesel and let sit for a few days before forcing anything, the longer it soaks the better, I have done this with a outboard motor that was dunked in salt water then sat in a shed for sometime it was frozen solid and after a few weeks in the drum of diesel it was freed up and is still going to this day.

Ashley

I leave the engine in the frame. Pull off the head. I soak the pistons in transmission fluid. After a few days, I then rock the bike hard in 4th gear a couple times a day. After a few days of rocking the pistons free up. Sometimes I heat the cylinders. I find it easier to rock the engine in the frame. You need to be patient. Never failed me yet.

Pull the plugs. Fill the cylinders with a 50/50 mixture of acetone and ATF. Put the plugs back in, one turn by hand... in other words very loose. Put a heat lamp (make shift is fine) on each cylinder, wait 3-4-5 days, or longer. Then, as suggested rock it back and forth in fourth gear...... If nothing happens, wait 24 hours and try again. If the engine is not free after a week, then pull the head. I predict it will free itself without pulling the head. Although pulling the head may be necessary later for other reasons, I would try and avoid that for freeing the engine. $0.02.

Don't get ambitious until you really need to. Follow R.R. 's advice.
Remove the spark plugs.
Put a small amount of oil or A.T.F. into each spark plug hole.
On centerstand in 4 th gear grab the rear wheel and try to move it several times a day , or even try kicking it in neutral.
Get a friend to push start style , drop the clutch whilst in gear and the shock might free the pistons up.
All with the plugs removed to eliminate compression factor.
Mine had that problem once one spring and used oil in spark plug holes and a curious heavy helpful stranger to kick it over and it was free. Fired up with only a few seconds of smokings and happiness.

Mine was locked up when I got it also. I pulled the plugs and filled each cylinder with diesel fuel and let sit for a few days. I then did the rocking back and forth in 4th gear and it broke free. Maybe I got lucky but it worked for me. Good luck.

Thanks. Mine has been sitting for 30 years in a not so well protected garage.

Ron L said:

Remove the engine from the frame and pull the head. Soak the pistons with your favorite concoction. Kroil, ATF/Acetone, kerosene, etc. After several days, try driving the pistons down the bore with a hefty block of wood and moderate hammer taps. If all else fails and the pistons are not at TDC, remove the cylinder nuts and split the cases, and remove the rods from the crank. Now you can take the cylinders to a press and push the pistons out. This will destroy the pistons, but the chance of saving them is slim anyway. Protect the rods and support the cylinder by the base. Patience and perseverance is needed here. I have only needed to use the press method once.

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I've had two engines over the years that were stuck badly enough to follow this path. A word of caution though, on the first engine I positioned the cylinders in the press the right way up (top at the top) and pressed downwards on the top of the pistons. All went well until the ring land area of the piston got to the the relatively poorly supported area at the bottom of the sleeve (where it sits proud of the cylinder muff) and cracked the sleeve. The next time I needed to do this I put the cylinder in the press upside down and pressed on the con rod, it worked like a charm and no damage to the piston (which was buggered anyway) or the con rod.

Fill the bores with Coca-cola let it soak for a couple of days then rock the crank by what ever method you choose keep topping an rocking it until it turns. I have freed-up car and bike engines with it I am told the Phosphoric acid in coke is aggressive enough to break down the corrosion.
Good luck with you project.

Whatever method you use to free it up don't be tempted to start it
It'll do more harm than good
Get it to free up then at least strip the top end
The bottom end should be ok because Norton's protect their bottom ends their selves

How about sticking a borescope in first to see what you're up against? If it's just a little bit of rust then I like the "soak with your favorite elixir like the ATF mixes" and try to free it up. If it's a solid mess of rust then there's no point.

I have freed up a tractor engine with the ATF/diesel mix and it is still running decades later. The tractor restoring community sometimes resorts to adapting a grease fitting to a spark plug air hold and loosening the valves until closed and and using a grease gun to move the pistons,which is generally considered a little gentler than smacking them with a block of wood. Grease gun can develop lots of pressure.

I've also heard of using a similar method with a porta power like a body shop uses or even the remote hydraulics from a tractor.

Sometimes the above methods are employed and it's found the engines run fine and other times they're used just to disassemble a severely rusted mess for overhaul.

if the pistons will not free with heat and soaking for a few days do not be tempted to press the pistons out i have seen many cylinder blocks cracked this way
best thing is to carefully drill a series of holes around the outside of the piston crown staying clear of the bore the rings are the problem cast iron liner rusted to cast ring by removing the piston top and
inner structure around the lands by drilling the piston top can be removed in pieces and with heat / freeing oil applied to what remains of the piston skirt they normally let go

bear in mind if the pistons are stuck they are scrap already if the cylinder is in good shape it will re bore to the next oversize and considerably more expensive than pistons , it is a big risk putting it in a press
i have tried this with a BSA A10 block the pistons moved downwards from TDC but pulled of the lower section of the liner right off on exit expensive lesson learnt the next one i drilled off the tops and removed
the seized pistons without damaging the cylinder block which was still serviceable after a re bore