Hello,
I have a aquired a motor (non mini but that doesnt matter) that is seized, at some stage in the last 25-30 years where it was sitting in a shed, somehow water has gotten into the cylinder, I pulled the head, and the bore had some surface rust, but came up fine after a sand with wet rub, however the piston is seized in the bore. I assume that its due to the rings rusting to it, but is there any sure fire way of unseizing the little sucker, or is it a bin job? Its currently got a mix of diesel, canola oil and WD40 sitting in the bore above the piston, but because its a 2 stroke, it seems to be able to leak out of the damn holes aorund it faily quickly.

Chris

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I can only please one person per day,
Today is not your day,
Tomorrow is not looking good either.

ur doint the right thing, after a day or two with WD40 , split the casing and pull out the crank, rod assembly

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A good friend will come and bail you out of jail...but a true friend will be sitting next to you saying "Damn...that was fun!"

being a 2 stroke i would say its a big end ..

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A good friend will come and bail you out of jail...but a true friend will be sitting next to you saying "Damn...that was fun!"

might be a good idea before you pull the crank out to try every couple of days after topping it up with crc/oil/whatever to rotate the crank, forwards, backwards etc... to unsieze my midget motor I put crc and oil in the bores and rocked the car while it was in gear...

I will keep doing what I am doing then, and resist the urge to start belting the living hell out of stuff with a sledge hammer, sadly patience is not one of my strong points.
Thanks Guys

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I can only please one person per day,
Today is not your day,
Tomorrow is not looking good either.

thats a good idea

can get a large breaker bar + socket on the end of the crank and get some movement out of it?

I've got the same prob with a Honda CB750 that was parked in a shed for 9 years. I've had WD40, then oil in the bores 6 months now, bugger still won't budge.
I put a torque wrench on the crank bolt at alternator, gave it 50lb/ft to rock it and still no turn over. Crank does rock a poofteenth..
Ah well looks like motor out, head off, block of wood and a BFH needed...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

try to diesle flush it too.

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A good friend will come and bail you out of jail...but a true friend will be sitting next to you saying "Damn...that was fun!"

dodge that picture is hypnotic

After reading that molasses trick in a post earlier today I think I'd give that a try.

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67 Traveller - Needs restoration
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Molasses is very thick. Maybe vinegar would work better?
I have used vinegar on slave cylinders that the pistons were seized so tight that you could not move the piston with a hammer. After a few days in vinegar the pistons came out.

Heat is also another thing to try. If you have access to a hot water hose (I have a Kerrick hot water pressure washer) you can heat up the cylinder and it will expand a little so that you may be able to move the piston. If it is a single cylinder engine you may be able to heat it up in the laundry tub.

I wouldn't try molasses in most motors to unseize them, they have aluminium pistons, and molasses eats it.
use molasses only on iron and steel parts....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Park it at the top of your sloping driveway pointing at the house , leave it in gear, handbrake off. Motor will defininitely un-sieze. Guantareed.



(yes, I know you said it's a mot a mini - but a two stroke engine)

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1958 Morris Minor 1000 - "Nigel"

just it does bloody matter.....


it means that this post shouldn't have been in Mini Chat

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Digressing slightly , I had a series 1 landrover with a similar problem , leaving it sit with wd40 etc in the bores didn't do any good till a mate came up with the bright idea of taking the sump off , turning it upside down and putting the wd40 mix in from the underside as well . It'd had a week sitting right side up with it supposedly seeping down from the top followed by a few days upside down with it seeping the opposite way . It must have met in the middle because it turned over easy after that . All we could come up with for a theory was the rings had rusted in so well that the mix could penetrate the top set but not any further , putting it in from upside down meant it got through all of the rings . Good luck .

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