spark plugs

[shaun]

I have 4 very stubborn spark plugs that have been in a volumex for a very, very long time. After three weeks of allowing petrol/diesel/oil to bath the plugs they have no intention of moving. Before I move up to some big bars and big leverage, any tricks as I'd be really annoyed to damage the head?

[BAS]

Have you tried undoing them with the engine hot?

[chris.richard]

Before I move up to some big bars and big leverage,

Hmm, careful. This is my extension after torquing up my rear hub nuts yesterday :(

[catswhiskers]

Fancy that Chris, I got one just like that doing the same job. We must start a collection. :rolleyes:
I finished up borrowing a lorry wrench and socket from a neighbouring company.
They just dont make things like they used too. :D

Mick

[strat6v]

You jumped up and down on it then :D

[catswhiskers]

Before I move up to some big bars and big leverage, any tricks as I'd be really annoyed to damage the head?
Shaun,
While it might sound strange, I often find that if you actually try tightening them, just a fraction mind, that can release the seat between the threads and allow them to be unscrewed quite easily. Good luck.
Mick

[rutthenut]

Don't like the idea of too much force on ally threaded parts, but have you tried using an impact wrench on top of the plugs? I'm thinking of the type that has a spring-loaded 1/2-inch socket drive on a 45-degree channel. You thump the top with a heavy hammer and it translates that into a twisting action onto the socket.

The concentrated shock and turning force from one of these can unlock many siezed connections. Or it may be too much :(

[chris.richard]

What about an impact driver? If you can get the head down to a garage if you haven't got one yourself.

[rutthenut]

What about an impact driver?

That's what I meant!

Dunno why I typed 'impact wrench' above :confused:

[chris.richard]

I meant the air driven torque thingy!

[shaun]

The long metal bar technique worked them loose, being Fiat plugs, rusty on top part of thread and full of carbon on the lower part. The head threads look ok and new plugs went in well enough so all is well. Bit of coolant and the engine should run, he says tempting fate.

[David May]

I don't know if anybody else approves, but I've been using a little smear of Copaslip (or however its spelt, copper-based grease) on my plug threads for decades, with no problems.