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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Sat Mar 15, 2014 7:33 pm Post subject: Part stripped spark plug thread ..alloy head |
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Bugger
I must have removed and reinserted spark plugs in the Stag more times than .....well I have done it a lot !
Today whilst bringing the Stag out of winter hibernation I removed all the plugs to check and clean. All was well apart from putting the plug back in number 4 cylinder, actually one one the easier cylinders to access the plugs.
I always screw the plugs in with thumb and forefinger , only using a wrench for the final tightening ......No 4 plug did not want to go back , the thread on the plug was clean and fine after 10 mins of trying to fit it , I decided to run a plug tap through the thread, thinking it may just need cleaning up.
The tap also took some persuading , but did take , but only for a turn and a half , then it went stiff What do I do back out or carry on?....I backed out a few times, but then decided it was all or nothing, and ran the tap with what I would describe as medium force.
So I can now insert the plug , but with only half the turns it should have, the plug seals and the engine runs fine, so what are my options;
Leave as is until there is a future problem
Put a helicoil in now, it's one of the easier cylinder to do
Never change plug 4 again !
Advice welcome
Cheers
Dave |
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kevin2306
Joined: 01 Jul 2013 Posts: 1359 Location: nr Llangollen, north wales
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Posted: Sat Mar 15, 2014 8:06 pm Post subject: |
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Id leave it and see how it goes, maybe a smear of copperslip on the thread to ease it a little?
Kev |
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Rick Site Admin
Joined: 27 Apr 2005 Posts: 22446 Location: UK
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Phil - Nottingham
Joined: 01 Jan 2008 Posts: 1252 Location: Nottingham
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Posted: Sat Mar 15, 2014 11:27 pm Post subject: |
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Been there done that and everything correct to the book and I also agree with what has been said ie leave it well alone.
You have nothing to loose - remove it only when you have to - then use an old plug as thread chaser to clean out the threads - this has worked for me twice now without problems and both are still OK after 10+ years
NEVER EVER remove/replace plugs when an alloy head is even remotely warm leave 24hours min. Use thread lube to replace and quarter turn MAX.
I did loose a plug on on my P5B V8 because of under tightening
and often find them then "loosish" _________________ Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2 |
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ajlelectronics
Joined: 04 Oct 2010 Posts: 168 Location: Gloucester
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goneps
Joined: 18 Jun 2013 Posts: 601 Location: Auckland, New Zealand
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Posted: Mon Mar 17, 2014 1:11 am Post subject: |
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Dave,
I presume these are alloy heads? If so, when you next have to remove that plug the best answer is to Helicoil it, and if I were in your shoes I'd bite the bullet and do the whole lot as an insurance for the future.
If Triumph hadn't been so cheap-skate they'd have used steel inserts in the first place. Fine threads (M14 x 1.25 if they're standard plugs) are not suitable for soft materials! My 1964 BMW motorcycle had steel plug inserts in its alloy heads, and there was never a problem in the 36 years I owned it.
Richard |
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peter scott
Joined: 18 Dec 2007 Posts: 7118 Location: Edinburgh
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Posted: Wed Mar 19, 2014 5:37 pm Post subject: |
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I'd be inclined to fit a Helicoil now otherwise you might end up with an emergency repair instead of one at your leisure.
Peter _________________ http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon |
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D4B
Joined: 28 Dec 2010 Posts: 2083 Location: Hampshire UK
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Posted: Wed Mar 19, 2014 5:44 pm Post subject: |
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How do you prevent swarf getting in the cylinder when helicoiling?
or is it only to be done with head off? |
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goneps
Joined: 18 Jun 2013 Posts: 601 Location: Auckland, New Zealand
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Posted: Wed Mar 19, 2014 10:41 pm Post subject: |
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Safest to remove the head(s), of course, but in dire circumstances a liberal coating of grease on the tap will retain virtually all of the swarf. Ditto for snapping off the tang of the Helicoil. |
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ukdave2002
Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire
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Posted: Sat Mar 22, 2014 8:02 pm Post subject: |
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Thanks for the replies
I'm going to see how it goes! Logic being that the worst that can happen its that I may loose 1 out of 8 cylinders, so would probably be able to limp home
I have fitted inserts before with the head in situ, doing as Richard suggested greasing the drill and tap, but also making sure that the inlet valve is open with a plate on the carb, tapped to take an airline fitting so that compressed air can be blown in, encouraging swaf to stay out of the cylinder, + it's an aluminium head so whilst any contamination in the cylinder is not desirable, it's softer than the rings and cylinder walls.
Will keep you posted
Dave |
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winchman
Joined: 21 Feb 2014 Posts: 235 Location: Merseyside
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Posted: Tue Apr 01, 2014 11:15 am Post subject: |
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I have used a Dyson with a straw taped to the end of the hose, it works well. _________________ It will come in handy even if you never use it. |
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Rosco663
Joined: 17 Dec 2012 Posts: 257 Location: South Australia
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Posted: Sun Apr 06, 2014 2:28 am Post subject: |
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ukdave2002 wrote: | ..........making sure that the inlet valve is open with a plate on the carb, tapped to take an airline fitting so that compressed air can be blown in, encouraging swaf to stay out of the cylinder,...... |
Excellent idea _________________ Rosco |
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Greeney in France
Joined: 06 Mar 2008 Posts: 1173 Location: Limousin area of France
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Posted: Sun Apr 06, 2014 9:01 am Post subject: |
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I dont know if it past this but I have a couple of different sizes of these and they work really well.
You put then in, find the inner threads and then expand them to unthread.
_________________ www.OldFrenchCars.com
We do these things not to escape life but to prevent life escaping us |
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Jonv8
Joined: 28 Jan 2009 Posts: 66
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Posted: Thu May 01, 2014 6:24 pm Post subject: |
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Greeney in France wrote: | I dont know if it past this but I have a couple of different sizes of these and they work really well.
You put then in, find the inner threads and then expand them to unthread.
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That is a tool I've been trying to design in my head for ages....
Who makes them ? |
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Greeney in France
Joined: 06 Mar 2008 Posts: 1173 Location: Limousin area of France
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Posted: Thu May 01, 2014 6:27 pm Post subject: |
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Its a Sealey MS003 _________________ www.OldFrenchCars.com
We do these things not to escape life but to prevent life escaping us |
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