Spark plug problem

[Tapitha]

I decided to fit a new set of spark plugs to Tapitha's engine. Two of the old ones unscrewed without too much trouble, no.4 needed a bit of force but number 2 would not unscrew even with a 3ft steel tube slotted onto the spark plug spanner. The tube bent! Some gorilla had no idea how to fit spark plugs! Fortunately the car goes OK with the old plug.
Please has anybody got an idea of how I can get this plug out without injuring myself, the engine or the car?
Thanks,
Mike

[MarkyB]

You could take it to a garage and let them use an air gun on it.
The sort of thing they use to over tighten wheel nuts, but in reverse

[dalebrignall]

sounds like the threads are cross threaded i would take it to a engineering shop and let them deal with it in case it snaps ,if it does they can helecoil it .

[bmcecosse]

Just keep using it for now - and look for another head meantime. Don't do anything to it - or you will end up car-less. What engine/head is it? A wee touch of copper slip on plug threads doesn't go wrong - and they should ONLY be done up (and un-done) using a speed-brace - I keep one under the seat with plug socket attached.....

[JOWETTJAVELIN]

As suggested - a replacement head.

It's never a good idea to over-tighten plugs, as the washer becomes compressed eventually preventing a gas-tight seal in addition to the problem you've got.

[philthehill]

I think that there is some over egging of the problem here. Suggestions of replacing the head are way over the top.
The cylinder head plug threads are very resilient in the cast iron head unlike an aluminium head and me ever being the optimist through many years experience of working on 'A series heads I doubt that they are damaged or even damaged beyond repair. I suspect that there is nothing wrong other than you needing to use the right tools. A 3ft tube through a standard plug spanner is bound to bend unless it is of a very high tensile strength.
A good soak with penetrating/release oil (NOT WD40) before attempting the plug removal will help matters along.
I would suggest that you get a proper 1/2" square drive deep socket 14mm plug spanner combined with a sensible 1/2" socket 'T' bar/power bar and I believe that the 'seized' plug will undo.
I have had them where it seemed impossible to remove the plug but with the right tools and a bit of care they were removed. If you can get the plug started to undo tighten it/undo it/tighten it/undo it work it backwards and forwards will help free it considerably
When the plug is removed clean up the threads in the cylinder head by using a 14mm plug thread chaser and if you have not got access to one use an old 14mm plug with a flat filed on the threads and screw that into the plug holes to clean up the threads. Make sure that you put some grease on the threads of the plug thread chaser/old 14mm plug which will help to collect and hold any carbon/dirt from the cylinder head plug threads. Give the engine a quick turn over to blow any carbon/dirt out of the cylinder head combustion chambers. Before refitting the plugs do as bmc says put a bit of Copper Ease on the threads of the plugs before refitting them (do not over tighten) and you will have no more problems.
Best of luck!

[JOWETTJAVELIN]

What was the outcome of this I wonder?

Sometimes I have had to give the spanner a good whack with a hide or rubber mallet to get things moving...

[bmcecosse]

Speed brace and hand pressure only when tightening.....

[M25VAN]

More likely to come out with engine hot or cold? If your car is a daily then a spare head would be handy anyway. You can refurb it while solving the plug problem and then have it just in case.

[bmcecosse]

My suggestion of another head was simply to ensure the OP didn't end up carless - since I gathered it is a daily use vehicle. Soif it all goes wrong - a head swap will have it on the road again in 30 minutes or so........

[Tapitha]

Hi All,
Many thanks for the advice about removing the spark plug. I am away for the next 4 weeks but will have a serious attempt when I return. I know the previous owner had everything done at a garage so I expect some apprentice was given the job of changing plugs without being given proper tuition.
Cheers,
Mike and Tapitha

[bmcecosse]

Leave it soaking in release oil while away....

[philthehill]

Spark plug thread chaser CHT261 available from Machine Mart Order code: 040210261 £4.79 inc VAT.

[bigjim]

where abouts are you i have thread chaser , helicoil kit and air gun if needed

[bmcecosse]

It was 3 months ago...... But handy set of tools there!

[philthehill]

Is the air gun to shoot those pesky helicoils which you chaser all over the place ???????????