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I've changed hundreds of spark plugs over the years.
I was going to change the plugs in my 3.0 BMW and did the first 5 but as I got to the front of the engine the plug in cyl-1 was very stiff.
I decided best to leave it as it was so stiff trying to unscrew it. It will unscrew a turn or two before the resistance in the wrench seems too much.
Has anyone else come across this sort of problem and what did you do?
I could just throw caution to the wind and unscrew it. But I'm having nightmare visions of the plug hole getting stripped and it then being impossible to put the replacement plug back in. Either from the thread being too mangled to accept the plug or with it being so stripped that the plug won't stay in the head.
However... there is the possibility as well that the plug being tougher than the thread it may just cut a nice thread on the way out and everything will be fine.
I tried heating the engine up and removing the plug after a high speed run but it seems just as stuck. I still think it would be best to remove it from the engine when it is hot as everything will be softer so less chance of breaking something.
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Last Edit: May 25, 2023 6:46:51 GMT by ejenner
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A new plug wont "cut a new thread" but you could get a thread tap to chase out any curse word in the threads, most likely you will need to put an insert or helicoil to make it good in reality.
if it does go a turn or two I'd wind it out, spray some penetrating oil or cutting fluid or atf down the hole, let it sit a little and wind the plug back in and out a few times to see if it'll come out further.
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May 25, 2023 12:30:30 GMT
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They make spark plug repair kits for most engines now, drill/tap & steel insert. Done a few in my time and easy to do. One link here repair kit |
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May 25, 2023 18:19:39 GMT
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They make spark plug repair kits for most engines now, drill/tap & steel insert. Done a few in my time and easy to do. One link here repair kitSeems to be around £260 for a timesert one... that's a bit much. |
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stealthstylz
Club Retro Rides Member
Posts: 14,829
Club RR Member Number: 174
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stuck spark plugstealthstylz
@stealthstylz
Club Retro Rides Member 174
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May 25, 2023 18:50:55 GMT
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Whilst it's still driveable ring some local engineering places and see if they can do a thread repair on it, then drive it to them and take the plug out in the car park. We charge £25-30 to fix it if the car's at work, but considerably more if I have to drive out to the job.
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May 25, 2023 18:59:27 GMT
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Whilst it's still driveable ring some local engineering places and see if they can do a thread repair on it, then drive it to them and take the plug out in the car park. We charge £25-30 to fix it if the car's at work, but considerably more if I have to drive out to the job. That's a good suggestion. |
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May 25, 2023 19:37:47 GMT
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They make spark plug repair kits for most engines now, drill/tap & steel insert. Done a few in my time and easy to do. One link here repair kitSeems to be around £260 for a timesert one... that's a bit much. Wow, last one I did (some years ago now) was about £20! it was a vauxhall though. |
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I remember somebody mentioning it on more than one occasion. Helicoil gets a similar amount of publicity.
For that money you would be scratching your chin and wondering if you might just take off the head and get it skimmed / cleaned up + new gaskets. A more productive way of dropping that kind of wedge and the job still gets done.
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It will come in handy even if you never use it
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May 26, 2023 12:15:04 GMT
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^^^^ that's what I was thinking of.
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May 26, 2023 12:55:40 GMT
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I remember somebody mentioning it on more than one occasion. Helicoil gets a similar amount of publicity. For that money you would be scratching your chin and wondering if you might just take off the head and get it skimmed / cleaned up + new gaskets. A more productive way of dropping that kind of wedge and the job still gets done. if its an Aluminium block BMW engine that is the last thing I'd want to do as they have a reputation for stripping headbolt threads... |
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stealthstylz
Club Retro Rides Member
Posts: 14,829
Club RR Member Number: 174
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stuck spark plugstealthstylz
@stealthstylz
Club Retro Rides Member 174
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May 26, 2023 13:23:16 GMT
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if its an Aluminium block BMW engine that is the last thing I'd want to do as they have a reputation for stripping headbolt threads... That's "usually" after they've been overheated. I add the "" as I still wouldn't risk taking the head off if it's unnecessary. Spent many wasted hours bodging those stupid things back up so I can bolt them back together. |
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