Best penetrant to help remove spark plug stuck in an aluminium head.

I am attempting to remove two very reluctant spark plugs. They have not been shifted for over ten years and I suspect they are stuck with a mixture of carbon and burned-on oil. I have no reason to suspect they are cross-threaded, and they are the right length for the head so there is no carbonised lump at the chamber end as can happen when a long reach plug has been wrongly used in a short reach hole.

A modest degree of brute force and a well-fitting socket having failed I wonder if you chaps - who have doubtless come across similar things with some of your old iron - have any recommendations as to a good solvent/penetrant to help ease them free.

Thanks in advance,

Gyppo

Reply to
J D Craggs
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Not a clue, but I'd suspect the corrosion is electrolytic rather than coking. Are they at the bottom of a well which has sat full of rainwater ?

A useful trick for brake bleed nipples is to lightly warm up the aluminium, then melt a couple of icecubes onto the steel inner. This thermal cycling is quite effective at freeing them, and they're smaller so far more fragile. Not sure if you've got the access to do it on a spark plug though?

Reply to
dingbat

Try soaking inside and out of the cylinder with diesel and leave for a week and see what happens.

Martin P

Reply to
campingstoveman

Best stuff I have ever come across for such jobs is Millers Graphited Penetrating Oil, not cheap and it stinks, but leave stuff to soak in it for a week or so and it will generally come apart.

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has more info. Regards Dan

Reply to
Dan Howden

The heads are already off so I may be able to do something along those lines. Thanks for the suggestion.

Gyppo

Reply to
J D Craggs

Thanks, Martin,

I'll probably try Andy's hot and cold suggestion first. But if that doesn't work I'll leave the heads in a bucket of diesel for a week and get on with something else. If I'd thought they were going to be a problem I would have tackled them much earlier. All part of the learning curve I guess ;-(

Gyppo

Reply to
J D Craggs

Lots of things will work - Diesel, Plusgas (my favourite) WD40 etc, etc. All of them are much improved by heat & time taken in use. Being able to attack the plugs from both ends might be useful too.

I'd power wire brush off the carbon from the thread you can see & heat the head. Apply fluid of your choice to hot bits. Leave.

Now try *tightening* the plug a fraction, if it moves at all, you can then try undoing it as you've broken the molecular bond that grows across the threads when long in pressure contact.

Patience is a virtue ......... ;o))

Regards,

Kim Siddorn

Time flies like an arrow Fruit flies like a banana

Reply to
Kim Siddorn

Ah, PlusGas. There's a name I'd forgotten. Dad used to swear by that stuff. Worked like magic on 30-year-rusted sidecar fittings.

WD40 has been tried and found wanting. It usually does the trick, but not this time.

Smelly kitchen time again then ;-)

Patience I've learned... Via a few expensive broken bits when younger ;-(

Thanks for all the options, Gents.

Gyppo

Reply to
J D Craggs

Loctite do a fancy freezing spray intended for this sort of thing, it ought to have more effect than the ice cubes but is also many times for expensive.

Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Reply to
Tim Leech

One to bear in mind if the other things fail then.

I've got a can of 'burnspray' tucked away somewhere and that gets cold enough to produce frostbite if used carelessly. Might try that if I can fit the WD40 tube in the nozzle and 'pinpoint' the effect. I'll let you chaps know if it works.

Thanks, Tim.

Gyppo

Reply to
J D Craggs

If the heads are aluminium, then you may well break the plugs before they move, unless you have acess to oxy-acetlyene welding set, and can get the plugs glowing red hot.

The same thing will work with cast iron heads, but you dont need quite so much heat. You will find it unlikely that anything like pentrating oil is going to work on something like this, and heat is the only sure way to remove plugs without damage (unless you are very lucky).

Reply to
Ken

Canned air used upside down so the liquid sprays out, still more expensive then ice but handy and cold.

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Andre' B.

Reply to
andre_54005

Any idea what this stuff has in it?

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Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Reply to
Tim Leech

That's going to do wonders for an aluminium head.

Reply to
dingbat

I think the idea is to reclaim the molten aluminium and recast it....the plug should survive.

Alan

Reply to
Algernon

Well im told aluminium is bringing a good price at scrap yards at the moment.

Mike M

miley snipped-for-privacy@hotmail.com

Reply to
miley_bob

I wonder if any of you numptys actually work with aluminuim everyday? If not then lets hear what sensible suggestions you might have in reply to the OPs original question.

k
Reply to
Ken

Come on Ken...lighten up. You can hardly say that heating the plug to

300 degrees C above the melting point of the aluminium is a sensible suggestion.

There have been a number of useful suggestions already, I just thnk it would be more sensible to try them first to remove the plug than melting the aluminium from around it.

Personally I would go with long ong soaking first.

One thing that hasn't been suggested is soakiing in liquid paraffin of the chemist variety, not the ironmongers, warmed occasionally to assist penetration.

And plus-gas....theres nostalgia for you...I LOVED the smell of that stuff.

Alan

Reply to
Algernon

I wonder why usenet always seems to attract those who can tell others what to do, but dont have a clue themselves?

Having sucessfully removed plugs from aluminum heads after heating them with a torch, I know this works and doesnt result in a melted head!

Interestingly enough the eggsuckers might like to know that the melting point of aluminuim is 660 degrees C, and red heat for steel is 400 degrees C, and to actually melt something like an aluminium head you would need to put it in a furnace of some sort.

k
Reply to
Ken

I wonder why usemet always seems to attract those who can't resist an abusive dig at others who have tried to answer the question fairly and properly in the first place.

Join the killfile, Ken. Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk

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Reply to
Prepair Ltd

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