Overtightened sparkplugs

Yes, but don't think that you have much of a choice -- they've got to come out.

I don't see any downside to doing that and letting them soak for a while -- of course, don't use a huge amount.

 

If damage was done it was during installation. It won't likely happen during removal.
I have removed plugs that required sliding a floor jack handle (about 4 1/2 feet long) over a 24 inch 1/2 drive breaker bar to get plugs out. Never damaged a thread removing one.

 

I'm going to take on removing the air injectors (83 308GTSI) I know they are hard to get out. Would using this technique be acceptable or chance of damaging threads?

 

The only issue getting those out is the carbon build up on the nozzle.

 

Gadzooks.

Archimedes was right....“Give me a place to stand, and a lever long enough, and I will move the world”

 

Prior to purchasing my current 488 I was interested in one that was at possibly the UK's oldest established Ferrari dealer. Upon enquiring about the car I was informed it was being prepared for the showroom and they would contact me when it was available to view. Time went on and no call was received so I contacted them again and was told the car was in the workshop and they were in the process of removing one of the cylinder heads because there was a seized spark plug in there. This was a 6 year old car with 32000 miles.
Needless to say I didn't buy it.

 

Thats funny. If the plug really is that tight they'll need to bolt the head down to something to hold it. Its already bolted to a motor, leave it there.

 

Why? As yet you have not related any knowledge of thread damage. You only said it was over tightened. Loosen it and screw it out. No hand wringing involved.

If it is cracked loose and does not thread out that is a very different situation. You have the cart a few miles ahead of the horse here.

 

Well that definitely makes sense. I didn't question them any further having decided against the car but maybe they thought the thread would become damaged during removal and would need to be helicoiled.

 

I suspect you were not told the entire story.
In any event, moving on was a good decision.

 

If you break the plug, you can get a tool from AutoZone that will cut left-handed threads into what remains and help you get it out. This was a common occurrence, on certain late model Ford Mustangs.

 

You could attempt to remove the plug while the engine is still wam. If you've got crude in thet thread this may help.

 

Do not use antisieze. Modern plugs and more specifically NGK say do not use it.

Please, lets not get stupid about this. A plug is stuck. Take it out and replace it. Dont follow someones stupid repair with more stupid repairs.
Leave your grease bottles where they belong lost in the garage somewhere.

 

Because Ford used a specific plug design that was prone to breaking. The tool was designed for that type of plug only. Apples and oranges.

 

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....or you can just put an airtool to it. Slow ripping torque is more potentially damaging than shocking blow of an airtool.

 

Asking for a friend...

No but seriously, please educate me. How can you tell the difference between 'overtightened' plugs and ones that are' seized ' in place over time from heat cycles? I would have thought that over tightening fractures the porcelain on the plugs. But I am no mechanic sir.

thank you

 

All that drama for over tightened plugs. People get a grip.
Some of you would put a tourniquet on a paper cut.

 

You can't . But a "seized" spark plug is more often due to galling (quasi-welding) of the threads during over-tightening than heat cycles, but corrosion can play a role, too. The porcelain of a "normal" spark plug would break only if the metal bottom piece (with both the threads and the hex drive feature) was so under-designed that it flexed a bunch when you put huge torque on the hex drive feature, but, even if the porcelain breaks, that doesn't change the issue that it's the metal bottom piece that needs to eventually come out.

 

In my experience galling has a great deal more to do with some thread issue or debris issue and independent of simple over tightening. It is partially due to debris in the threads and is one of the reasons antisieze is no longer considered appropriate. It just attracts and collects debris.

 

I would advise that you get a good read on the mixture before changing anything.

It used to be that the jetting changes required were very well defined, and usually in the neighborhood of 15-20% leaner based on the same amount of loss of air density. Now, due to the Ethanol fuel which burns leaner, sometimes we see cars coming here from sea level that need much less of a change in jetting than would be expected.