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could anyone enlighten me as to how to remove a siezed piston from the engine block..I have been able to remove 2 of the connecting rod caps and bearing shells but because of the position of the crank I cant get to the other bolts to remove the remaining caps and shells.Short of wolloping it with a piece of timber and a lump hammer to loosen it im bit lost.... knowing my luck I.l probably bugger the crank.....Any help would be appreciated......Many thanks....frank

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I don't see clobbering the piston with a heavy hammer,

with a block of wood in between, is going to damage

the crankshaft. Pretty much standard practice.

 

Give it a really good soaking first - don't be too impatient.

Various concoctions, one of which is described above.

 

Obviously make sure the con rod ends with the cap

removed is kept clear of the crank when you bash the

piston down.

 

AlanR

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Trouble is alan I managed to undo 2 of the conrods from the crank but there are still 2 connected and I cant get to the bolts because of the crank being held by the seized piston in the wrong position...... should I remove the rear main bearing cap,the front sealing cap and the centre main bearing cap and then go for the big hammer and block of wood remedy....I.E. (the fine adjustment tools)...frank

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Thanks derek....got the piston covered by bout 20 mm of WD40 in the bore at the moment...have done for bout 3 days but doesnt seem to be doing much good so may have to try your alternative method.....thanks for the help....frank

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Try some genuine pentrating oil, it works wd40 does not!

Chris

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Use diesel dear Frankie, dear Frankie, dear Frankie...use Diesel.

 

Much better than WD40.

 

Mick Richards

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I'm with Mick in this one diesel is the way to go, it's been tried and tested method for a millennia for freeing off siezed pistons. flood the barrel/bore with as much as you can and let it work it's magic, and you should be able to work it free.

 

Gavin

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Hi Frank,

don't undo any of the crank bearings. These will support it whilst you are attacking the piston.

 

Has the piston seized in due to corrosion. If so then a proper penetrating fluid (plus gas etc). WD40 is used to take up space on a shelf.

Diesel is the alternative evil brew that works.

 

Using a decent lump of wood on top of the piston give it a good whack with a very large hammer - 5+lbs.

It will not move far with one hit so keeping the other rods out of the way is easy.

 

If the piston has seized due to lack of oil then it may well be anchored more tenaciously. Do much the same as above but hit it harder.

 

Roger

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I hate to hit anything but you will wind up hitting this.

 

When I hit something I plan carefully how I hit it.

 

In this case you want a block of alloy that sits on the top of the piston. Forget about wood.

 

You hit it with this:

https://flic.kr/p/nNLfA7

 

4lbs of lead. Take two hands to swing.

This is a "dead-blow". Its quite different to a steel hammer that rebounds.

 

Normally I swing it about 8in! You would be surprised what will move with just a small blow like that.

Its about tranferring energy from motion into a sudden shock.

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While I sympathise with the view that diesel is a better freeing fluid than WD40, please remember it is carcinogenic and mutagenic. Wear nitrile gloves, or use a purpose-made pentrating fluid. If you want to try something designed for a diffferent purpose, try a cheap coca-cola, the phosphoric acid will free parts seized by rust, and it's cheap from one of the discount supermarkets.

 

You probably need a turning force on the crank while you're hitting the piston.

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