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Spark Plug hole repair

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Old 05-14-2020, 06:12 AM
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Default Spark Plug hole repair

Hi all.
Has anyone used a spark plug helicoil or timesert in a V12 HE engine. I think I’m going to have to repair the thread in my number 1 A bank plug.
Rob.
 
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Old 05-14-2020, 09:13 AM
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Hi Robbo

'Greg' will be the Expert on this but is it really that bad?

Just had a look on ebay and you can get a Spark Plug Chaser to clean out the Thread and re-cut it

Have you tried a Spark Plug, they don't have to be very tight as you know
 
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Old 05-14-2020, 09:25 AM
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I haven’t actually got the offending plug out yet. It’s probably about 3/4 unscrewed so maybe 5mm of thread left in the head. Thing is its now spinning without coming out so I’m pretty sure I will need to use an insert of some description. I can screw the plug back in just not all the way out. Not really sure ho to proceed now. I always thought this one would be a bas***d as it was an odd NGK plug. All the others were Champion.
Rob.
 
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Old 05-14-2020, 09:45 AM
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Hi Robbo

Looks like a Garage or maybe the P.O. has taken a shortcut and not bothered to change the Plugs that are under the Air Con because they are a PIA to get to

I am guessing you know they are Tapered Thread?

So if you can manage to get it out, then you could still be in with a shot of putting a new one in without doing anything
 
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Old 05-14-2020, 01:11 PM
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Well at last the bloody thing is out. Managed to get the last few threads to bite and wound it out. I will need to put an insert in the head as there’s not much left of the old threads. It’s only took me a month to get this bugger out.
Rob.

 
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Old 05-14-2020, 03:57 PM
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Hi Robbo

You can get a Spark Plug Thread Chaser/Cleaner on ebay for about £7

That's the way that I would go to start with and keep the Helicoil as the 'Nuclear Option' as if the Helicoil goes wrong, well I don't need to say it do I

In fact I think I would try a New Plug and if it went in just a bit over hand tight, then I think I would leave it, as when I changed all the Plugs on my Car I only just nipped them up and they haven't moved yet

A mate of mine who was watching me, kept saying they want to be tighter than that but I resisted the Temptation to follow his advice which is why I prefer to work alone and not have anyone help me

Your Car your call

But I wonder what 'Greg' 'Grant' or 'Jagboi' would say
 
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Old 05-14-2020, 09:01 PM
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Hell Rob - what an effort.
The thread on the spark plug looks stuffed....

Very scary - spark plug chaser does sound like the go.
When I did mine I had to get a large pipe on the ratchet.... I was saying a little ... word to the Jag Gods.
But they came out fine.

Make sure you put some antisez on the new plugs, screw in finger tight, the turn 5mins...seemed to work for me.
Look forward to the update!
 
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Old 05-15-2020, 12:56 AM
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Originally Posted by orangeblossom
Hi Robbo

You can get a Spark Plug Thread Chaser/Cleaner on ebay for about £7

That's the way that I would go to start with and keep the Helicoil as the 'Nuclear Option' as if the Helicoil goes wrong, well I don't need to say it do I

In fact I think I would try a New Plug and if it went in just a bit over hand tight, then I think I would leave it, as when I changed all the Plugs on my Car I only just nipped them up and they haven't moved yet

A mate of mine who was watching me, kept saying they want to be tighter than that but I resisted the Temptation to follow his advice which is why I prefer to work alone and not have anyone help me

Your Car your call

But I wonder what 'Greg' 'Grant' or 'Jagboi' would say
Totally agree OB. I had a plug once that when I changed was actually loose, not nipped up at all, and there had been no ill effects over 10,000 miles! In the thechaser as you said, and try a new plug using loads of anti-seize. with nothing more tight than hand-nipped up with your hand over the ratchet clicker-end, NOT the lever.
If the plug will not even nip up, the the helicoil option will work, BUT get someone experienced in using those things to do it, as you say, one slip and....
 
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Old 05-15-2020, 01:08 AM
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I could always JB Weld the new plug in. Ha ha. If you boys think a chaser will work I will get one of these.
https://www.ebay.co.uk/itm/291171025832 Looks to a handy piece of kit and it will drag any crap out as it’s wound out of the head. I will update this as and when.
Rob.
 
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Old 05-15-2020, 03:47 AM
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I been reading while drinking, tuff life.

MAAAAAATE that deserves a bloody medal, and find the PO and smack him around a little.

I agree with Greg and Alex (OB), try a new plug before anything else, I would for sure.

Any swarf that a chaser may remove will drop inside. I have used one, on an old XK 6 cyl a lot of years ago, and dipped the thing in Wheel Bearing grease (sticky shiit), and got away with it.

You could be lucky.

If Helicoil is needed, PROFESSIONAL only, as one slip, and its engine out, and a whole new language to learn.
 
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  #11  
Old 05-15-2020, 08:48 AM
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Originally Posted by Robbo D
I could always JB Weld the new plug in. Ha ha. If you boys think a chaser will work I will get one of these.
https://www.ebay.co.uk/itm/291171025832 Looks to a handy piece of kit and it will drag any crap out as it’s wound out of the head. I will update this as and when.
Rob.
Looks a great bit of kit.
 
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Old 05-15-2020, 11:05 AM
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Originally Posted by Greg in France
Looks a great bit of kit.
I have ordered one. Should be with me Monday or Tuesday next week. I will let you all know how I get on.
Rob.
 
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Old 05-21-2020, 11:41 AM
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Well plug chaser arrived today. Bloody brilliant. Re cut the threads with plenty of grease on the tap wound it back out of the hole jobs a good un. The new spark plug screws in nicely and nips up when fully home. Here’s a picture of the tool and the swarf the tool removed and also the new plug in position.
Rob.





 

Last edited by Robbo D; 05-21-2020 at 11:45 AM.
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  #14  
Old 05-21-2020, 02:12 PM
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Have you tried chasing the threads?
You can easily and cheaply get a chase and see what things look like.
Once you install a Heli-Coil you can't go back.
I had one plug snap off at the head and i had to use an easy out.
The threads took some damage but after I chased them everything was Jake.
 
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