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Seized engine

I would be interested to hear any ideas of how to deal with a really badly seized engine. I guess lots of oil and heat but would like to know what useful methods have worked. Cheers, John

email (option): tinley@btinternet.com

Re: Seized engine

Hello John,

You could bolt a plate on top of the cylinder with a grease nipple, top it up with oil and put it under pressure with the greasegun. I never tried but assume it works well with a bit of patience. Good luck, Michiel

email (option): m.wijbenga@hotmail.com

Re: Seized engine

If you can find a steel container large enough to immerse the engine in old motor oil , boil it for a few hours . I have known this to work un-seizing a six cylinder engine which had been seized and had lain on a farm since the 1930's . Perhaps this combined with the idea of a steel plate bolted onto the barrel with a grease nipple welded to it? Definately not a good idea using brute force, though . By the way , if you use the boiling idea I's strongly advise you tp use a gas flame which is controllable , i.e dont do it over an open fire!

email (option): leifevans75@yahoo.co.uk

Re: Seized engine

If the piston is below tdc, I'd fill it with paraffin to the top, drop in a rag and light it, it has a dual effect of heating everything and the hot paraffin tends to flow into everywhere that it would take cold paraffin ages to get into. I've used this method to good effect a few times. I'd also take out the base nuts just in case it is the crank that has seized.

email (option): davmax@ntlworld.com

Re: Seized engine

John, all nice solutions if the seizing is partial. I had to cut away and drill at the piston on my WM20 cutaway motor to be able to remove it. Corrosion was worse on that since the openings had allowed immobility at all levels. Hope yours is better.

email (option): unpob@yahoo.com

Re: Seized engine

If the crank stll moves you could remove it's crankcases and then try getting in underneath if the piston is unserviceable, because it's a split skirt it shouldn't be too hard to prise it away from the cylinder wall and maybe use a bit of heat underneath it.

email (option): davmax@ntlworld.com

Re: Seized engine

Hi,
May sound a bit mad but I have used Coke - (lipsmackin' drinkable type rather than Columbian Marching Powder) to unsieze an old MZ engine. It freed the piston and after taking the cylinder barrel off used it to free up the crank.
I just poured it in and left it to do it's work.
This was full strength genuine Coke and not a cheap Lidl special.
It also cleans copper coins. I never drink it!
Regards
Clive

email (option): cliveandjo@lineone.net

Re: Seized engine

Thanks guys for some great ideas. Regards, John

email (option): tinley@btinternet.com

Re: Seized engine

I have freed a seized motor with coke many years ago too, it worked for me at the time although it may not on each occasion

Diesel has also freed off many a stuck top end

Hopevyou get sorted john

Jo'b

email (option): Jonnyob1@googlemail.com

Re: Seized engine

Whatever you do, take out the oilpump and drive , it will probably be seized as well. I stripped the drive and pinion trying to turn a crankshaft that had been sitting for years. Lesson learnt!

Re: Seized engine

If the piston is really, really stuck, and low enough, and diesel/WD40/ any other releasing fluids don't work, next radical step is to take the cylinder base nuts off, and lift the cylinder. Dismantle the bottom end from around the crank ( so the following doesn't eat it..)
Then immerse the cylinder/piston in a bath of caustic soda (sodium hydroxide) which will eat the piston and any carbon out. Obviously the piston will be destroyed, but it won't affect the cast iron cylinder. Pretty harsh method, but saves the crankcases and bottom end, and the cylinder. I watched a buddy dissolve a Triumph cylinder head down to a few valve guides and studs when he accidentally forgot it in a caustic soda bath after intending a quick carbon-loosening dip. Never answer the phone and leave it unattended when attempting this method...
Vince

email (option): bsa3man@rocketmail.com

Re: Seized engine

best tip yet vincent,but dont be going near it with a fag in your mouth as it gives off hydrogen gas.i suggested this method to a guy who had a seat stem stuck in a racing pushbike steel frame .ieven set up a test bath to prove it wouldnt damage the steel.he rejected my suggestion and clamped it to a radial arm drill,drilled down about 3''and the drill appeared through the wall of the tube cheers rick

email (option): richardholt@rocketmail.com

Re: Seized engine

Removing the pinion and oil pump first is a cracking good idea!

I generally soak the barrel in diesel or proprietary penetrating oil for a few weeks, then remove the head for inspection. If the bore is rusted and pitted, and the piston is NOT at bottom dead center (a worse-case scenario if ever there is one), I cut a steel plate or bar to fit over the piston, drill it to allow it to be fastened by the head bolts, and drill and tap for a half-inch bolt centered on the piston. Pad the piston crown with wood or soft metal, heat the cylinder and piston, and slowly add torque to the center bolt. It will come free, safely, cleanly and economically.

Caustic soda will work as described. Old service manuals advised a lye bath for decarbonising cast iron heads and barrels. But beware, it is very dangerous to skin, and especially the cornea of the eye. It is the best solution for a BDC piston jam.

Resist the temptation to hammer the piston crown. It will collapse a domed piston and jam it tighter. And beware of using compressed air: the head or barrel may explode!

The grease gun trick may work, but is an expensive waste of grease and quite messy at that.

Boiling in crankcase drain oil is courting disaster or divorce. Or both!

Jeff

Re: Seized engine

Hi ,I use straight white vinegar great for removing rust out of fuel tanks also,fill up and leave overnight

Re: Seized engine

i am a diesel fan it would be good if the piston is down the bore slightly hang the engine by the cylinder barrel put the diesel in and leave to hang not to high put something too cushion its fall dont use one from you front room couch would not be good for you relationship

Re: Seized engine

Regarding the earlier mentioned greasegun trick:

Today dismantled a seized engine, the piston was seized in the cylinder at almost TDC so couldn’t part the crankcase first because of the cylinder studs, so put the head back on and put a stud with greasenipple in the sparkplughole, topped up with oil and put pressure on with a greasegun, at first oil was leaking from the inlet port so topped up the port also and covered the inlet with a plate. Now pressure was building up and the piston was moving, so I can now confirm it works well... (if the valves are closed....).

Regards, Michiel

email (option): m.wijbenga@hotmail.com

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