Stuck piston and neck bearing question

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N0rt0nelectr@

N0rt0nelectr@

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I am still working on my 70 750 which came with a extra engine. The extra engine had a plug out of it for at least 10 years if not more and the LH piston is stuck. I have had Marvel Mystery oil sitting on top of the piston for a week now to no avail. Just applied heat to the point that the oil started to smoke but still it doesn't want to budge. Ideas? Better penetrating oil?

Next on my list of issues is that on later Commandos there is a spacer between the upper and lower neck bearings. On my 70 that isn't the case. Of course the trees are different from the later ones and this may account for the difference. Question is with there being two nuts one above and one below the top tree should I bother with the spacer?
 
N0rt0nelectr@ said:
I am still working on my 70 750 which came with a extra engine. The extra engine had a plug out of it for at least 10 years if not more and the LH piston is stuck. I have had Marvel Mystery oil sitting on top of the piston for a week now to no avail. Just applied heat to the point that the oil started to smoke but still it doesn't want to budge. Ideas? Better penetrating oil?
Click to expand...

On your first issue. If you have an air compressor, air pig for 3/8 QD fitting at your disposal. Then make up a tool using an old sparkplug and an air fitting 3/8 male QD. Remove the ceramic center of the sparkplug and braze on this male fitting to make the tool. Now mix up a 50/50 concoction of acetone and Dextron 2-transmission oil and pore it in the offending cylinder/s. let it sit for ½ hour and screw in the tool into your sparkplug hole. Next connect the air line into the cylinder sparkplug fitting. Leave the pressure on for a while to allow the oil to pass beyond the rings. Get a spanner on the output shaft (drive side) and rock the crank back and forth. It should let go and free the pistons from the cylinder wall/s.
Good luck.
Tom
CNN
 
Might back off valve adjusters to close valves then fill w dry beans/rice pour in hot water, plug then check next am. If stuck side on compress stroke so valve closed a Dixieland man would get out cutting torch set to neutral flame, snuffed out to fill jug, plug and spark off from a lawn mower or Norton ignition pulse, one hand to key on the other to cover vitals. Strongarm stuff is used for this - freeing old Brit iron single found in mud in drainage ditch so like sea bed crusted treasure that spun free afterward. Molasses soak for its organic acid and metal oxide chelating dissolving crust method might work too but slower.
 
N0rt0nelectr@ said:
Next on my list of issues is that on later Commandos there is a spacer between the upper and lower neck bearings. On my 70 that isn't the case. Of course the trees are different from the later ones and this may account for the difference. Question is with there being two nuts one above and one below the top tree should I bother with the spacer?
Click to expand...

The pre-1971 bearings are adjustable, these do not require any spacer.
http://www.classicbike.biz/Norton/Repai ... mmando.pdf
Section G6.
 
N0rt0nelectr@ said:
I am still working on my 70 750 which came with a extra engine. The extra engine had a plug out of it for at least 10 years if not more and the LH piston is stuck. I have had Marvel Mystery oil sitting on top of the piston for a week now to no avail. Just applied heat to the point that the oil started to smoke but still it doesn't want to budge. Ideas? Better penetrating oil?

Next on my list of issues is that on later Commandos there is a spacer between the upper and lower neck bearings. On my 70 that isn't the case. Of course the trees are different from the later ones and this may account for the difference. Question is with there being two nuts one above and one below the top tree should I bother with the spacer?
Click to expand...


What do you want to do with that engine? It MUST be completely dismantled, cleaned inspected and then begin replacing as needed. The rust/corrosion in the cylinder that was open to the elements (outdoors, I assume?) is severe. Totally destroying the piston to remove it MAY be necessary, thereby saving a cylinder for rebore.

The old romantic tale of freeing up a stuck engine with Mystery oil and she runs is so much BS, in some very minor cases it may run SOME, but the iron oxide quickly destroys everything in contact (rings/piston) with it.

Pictures please... :mrgreen:
 
concours said:
What do you want to do with that engine? It MUST be completely dismantled, cleaned inspected and then begin replacing as needed. The rust/corrosion in the cylinder that was open to the elements (outdoors, I assume?) is severe. Totally destroying the piston to remove it MAY be necessary, thereby saving a cylinder for rebore.

The old romantic tale of freeing up a stuck engine with Mystery oil and she runs is so much BS, in some very minor cases it may run SOME, but the iron oxide quickly destroys everything in contact (rings/piston) with it.

Pictures please... :mrgreen:
Click to expand...
I totally agree. Just see my thread about the sludge trap inside of the crank. why-you-need-check-your-sludge-trap-t20472.html
This engine sat for many years on the ground of a barn/shop. Bugs and rust and who knows what has lurked in there. :shock: Be diligent if you wish the engine to live for any length of time after startup.
Cheers,
Thomas
CNN
 
hobot said:
Might back off valve adjusters to close valves then fill w dry beans/rice pour in hot water, plug then check next am. If stuck side on compress stroke so valve closed a Dixieland man would get out cutting torch set to neutral flame, snuffed out to fill jug, plug and spark off from a lawn mower or Norton ignition pulse, one hand to key on the other to cover vitals. Strongarm stuff is used for this - freeing old Brit iron single found in mud in drainage ditch so like sea bed crusted treasure that spun free afterward. Molasses soak for its organic acid and metal oxide chelating dissolving crust method might work too but slower.
Click to expand...
I would avoid the beans and the water. :roll:
But Steve is right...if the piston that is stuck has the valves open then try first to back off the adjusters and if not enough take the head off and remove the push rods this ensures your valve remain closed. Place the head back on with at least the 4 or 5 bolts from the top using head gasket (that is) if it is still in one piece and do the air thing. I forgot that I did this maneuver.
Cheers,
Tom
CNN
 
Old hot rodder's trick to disassembling a junkyard find was to fill the offending cylinder(s) with dark cola. RC Cola was the best, since it has the highest percentage of Phosphoric Acid of all the colas. Yes, phosphoric acid. It's great at eating iron oxide.
You may have to let it sit a few days with RC in the cylinder, but it's helped me and others in the past.

Nathan
 
Duh its the phosphoric acid in sodaphosphate drinks the give them the tangyness that does the job so why add sticky stuff with dyes and cancer causing toxins out into the environment. There's enough phos acid in a can of cola to be a deadly emergency to the body and would kill ya dead as a door nail if not for the blood buffer systems giving up vital alkaline minerals/electrolytes then going direct to bone reserves which takes some hours. Even one cola a week prevents any bone rebuilding d/t the minerals washed out as a salt of inorganic acid. Organic solvents do not bother rust crust expanded wedging only brutes breaking it up over time with hammering shocks + heat cycles or weak pH acidic &/or chelating agents. Mechanics man hood tester.

I and a bunch of others have bad experience with frat hazzing in below freezing starting with onion bobbing in a tub of it so repluses me still.
https://www.google.com/?gws_rd=ssl#q=ho ... zen+engine
Stuck piston and neck bearing question
 
A trick John Deere tractor restorers use when finding a stuck piston is to adapt a compression tester fitting (or an old spark plug with the ceramic removed) to a regular zerk fitting, Grease guns can achieve tremendous pressure so they just pump grease in with the valves closed, of course, until the piston moves. This is done after their favorite penetrant potion has been allowed to act for the requisite time, chickens sacrificed if need be.
 
Thank you all for your thoughts and insight as to how I will remove this stuck piston. I do plan on striping in all the way down and inspecting each and every part before putting it back together.
The head is off of it and I was able to remove the other spank plug. I think that was a good thing in that at least that side doesn't have a stuck piston. My wife wasn't happy that I had the head in the oven to heat it and help me get the plug out. I might just put the head back on and try the air and penetrating oil route. All that will cost me is time and I have lots of that.
Again, thanks
 
My novice mechanic concern is if there's a risk to score bores enough to re-bore by forcing piston motion rather than just breaking piston crown up to free barrel then remove rest of piston from bore and decide from there. Of course I don't know a good way to break up piston or melt its top away for labor and engine saving.
 
You could fill the cylinder bore with Evapo-Rust (http://www.evapo-rust.com). You'd have to clean all the beans-rice, Mystery Oil, Molasses, and RC Cola out first to get it to dissolve the rust. Beyond that you could dissolve the piston using a diluted mixture of Sodium Hydroxide AKA. Lye, AKA Drano crystals. It will aggressively attack aluminum not to mention your skin.
 
Alan & hobot know there's only a few ingredients such as found in mole-asses that can chelate metal ions and both brands called EvapoRust contain them just w/o the sugary element that attracks bee's and pancake eaters. Some scope to be aware of on this stuff before poo pooing old school ways.
https://www.google.com/?gws_rd=ssl#q=ev ... ngredients
 
OK Steve, just a bit of sarcastic humor, Sorry. The discussion was making me hungry.
I've had excellent results with ER. I think the amount of chelation goo is higher in ER because it works overnight. Most of the molasses videos show people soaking things for days. Also ER is clear, it doesn't smell, and it won't attract bees and bears. I filter it afterwards and use it over and over. Great stuff.

In reality, I'd probably skip all the chemical warfare just use a block of hardwood and a BFH with some heat.
 
EvapoRust is a good one I"ll keep in mind if other expedient ways fail. Glad it ain't my Norton but am attempting to recover old Kolher twin cases I got in auction that ain't turning over on my first febble attempt. If ya make up a plug grease zerk, maybe mail it too me for a while after your successful use. There are also active electrolytic methods I'm not even considering looking into. There were a number of things rust fused on pre-Peel nothing worked till I cried online then like magic the mental collective changed quantum reality in my favor to release on next attempt with less stress-strain-pain, yet doing nothing different, so feel it was just enough keyboard strokes that worked for me.
 
triumph2 said:
why bother to put the head back on? the stuck piston is right in front of you.
Click to expand...
t2
Because the air pressure helps push the fluid past the rings. Also the air within the closed cylinder is creating a lot of PSI to help move the top of the piston gently. This trick was taught to me from a Rolls-Royce Merlin mechanic at the Canadian War Plane Heritage who fixes one of the few remaining flying Lancaster Bombers. It flew to England this summer. You could use grease as well but then you have quite the mess to deal with afterwards. My method would just require a shop rag.
There is more ways to skin this cat. Choose your medicine wisely.
Cheers
Tom
CNN
 
This difference between even gentle grease pressure and air pressure wisdom occurs when it suddenly does the trick.
 
T. my only advice after all that good advice is to go gentle and work towards heavier methods until something gives. Are the piston(s) frozen mid point or T.D.C. : If lower level I would whack with wood shock after the soakings in those penetrants. But yes total teardown and measuring$. B.T.W. you should have come with us after the fall Milton swap meet to hike Rattlesnake Pt. ,climbers and rapellers on rock face some falling on overhang then line-shock rescues by loving wives anchored below with lines safetys. At the swap I scored a good non-notched clutch center w. basket and dia.spring for $25. Another friend scored a MK 111 kicker for $20 before I spotted it. Score. But less and less Norton stuffage for sure every year , But for $5 of curiousitys and socializings then fall hikings all goodly.
 
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