Help with spark plugs needed

[knotting_pot]

As the engine seems to be misfiring whether running on petrol or lpg I have been going through the obvious causes and so far have checked the spark plugs, changed leads, rotor arm and distributor cap...still the same . So today decided to change the spark plugs even though they looked in good condition. Got to number 3 and although it unscrewed easily by hand the new one would only go in 2 turns before getting stiff. I had put copperslip on the threads as I always do and am obsessive about screwing in by hand only. As it turned out at this stage I noticed the new plugs Halfords had supplied were wrong and so I set about putting the old ones back in. Again number 3 would not go past 2 turns. I turned the engine over in an effort to blow any debris out of the threads and tried again...no joy. I wiped the threads with a rag as best I could..no joy.

Can anyone offer any suggestions? I am tempted to just screw the thing in with my ratchet drive but dont want to damage the thread. But I need the car for work at 6am tomorrow so am getting panicky.

 

[Toolbox]

I know it’s a bit late in the day now for you to go and find one, but you could do with a Spark plug thread chaser, to clean the threads out.

 

[knotting_pot]

Doesn't debris then fall into the combustion chamber?

 

[Terranosaurus]

Doesn't debris then fall into the combustion chamber?

Yes but not a big issue - people fit helicoils with the head insitu with no problems - you could stick a vacume cleaner tool into the area as you do it if you're worried.

 

[knotting_pot]

Doesn't debris then fall into the combustion chamber?

Yes but not a big issue - people fit helicoils with the head insitu with no problems - you could stick a vacume cleaner tool into the area as you do it if you're worried.

I will get a thread chaser tomorrow, I have 2 good car accessory shops at the end of my street so shouldnt be a problem. My wife is not working tomorrow so I can use her car for work. I should have a 14mm tap or is it 18? somewhere in the garage that we used to use for the spark plug in industrial gas burners but I didnt want to use this as it could cut another thread in the head.

 

[knotting_pot]

No-one local has got a thread chaser in, apparentley there is no call for them anymore. Machine Mart should have on in for me tomorrow.

 

[rustic]

Yes but not a big issue - people fit helicoils with the head insitu with no problems - you could stick a vacume cleaner tool into the area as you do it if you're worried.[/quote]
Don't think about it !!!! the vacuum cleaner will suck in a petrol air mix and as soon as it reaches the sparking motor...... Bang !
My Dad did this many years ago, on an old Bedford Dormobile when I was a child in the 1960's, he cleaned the air filter from the outside and...... the vacuum cleaner was in a thousand pieces.... The memory still haunts me... 40 + years on.. 8O 8O

 

[Terranosaurus]

Yes but not a big issue - people fit helicoils with the head insitu with no problems - you could stick a vacume cleaner tool into the area as you do it if you're worried.

Don't think about it !!!! the vacuum cleaner will suck in a petrol air mix and as soon as it reaches the sparking motor...... Bang !
My Dad did this many years ago, on an old Bedford Dormobile when I was a child in the 1960's, he cleaned the air filter from the outside and...... the vacuum cleaner was in a thousand pieces.... The memory still haunts me... 40 + years on.. 8O 8O[/quote]

That won't happen on a modern fuel injection engine like the T2/Mav 2.4 as no petrol will be present but yes it is a danger when dealing with carbueretors.