having snapped a spark plug in my corsa we used an easy out to get the thing out but now the threads are ruined.
the plug is baggy when fitted and not tight fit. are there any fixes that dont involve taking engine apart or buying a van?
Chat Forum
[closed]
spark plug bagginess
-
Posted 2 years ago #
-
not sure if some ptfe tape will do?
if not some sort of lock tight
Posted 2 years ago # -
That sparg plug will be under extreme pressure and heat.
Maybe loctite do some special paste, but i think you may be F*&^%$d
Posted 2 years ago # -
There is a threaded insert you can get which you screw into the head. Involves making the hole bigger with a tapered tap - use lots of grease to trap the swarf and keep most of it out of the engine.
Best bet is to go and ask your local engineering workshop if you have one - the sort of place that can skim cylinder heads, regrind cranks, etc.
Posted 2 years ago # -
Posted 2 years ago # -
Wot dave said - you can helicoil a spark plug thread - and if you grease the tap heavily most of the swarf stays on the tap so its a five minute job without dismantling the engine. To do it properly you need to remove the cylinder head but a helicoil without removing the head is possible
Posted 2 years ago # -
wot dave and tj said, don't be tempted to use ptfe tape or loctite as you need to earth the plug through the engine block otherwise it wont spark!
Posted 2 years ago # -
The one I used (many years ago mind) was more like a pipe threaded internally and externally than a traditional helicoil (like a spring). It had a certain amount of 'wall' there too.
One tip I got was once the new, bigger, thread is cut, clean off all the grease. Get the external thread wet, with water, before screwing it into the head. Grease the spark plug before you screw it in. The idea is to encourage the 'repair' to seize into the head over time, and not unscrew with the plug on the next service.
This baby should do it and be cheaper than taking the head off.
Posted 2 years ago # -
Don't grease the spark plug thread, the grease can't take that kind of heat and will become a horrid gungy mess, it'll also make the plug run hotter and stop it earthing through the head ... instead, rub a pencil over the threads this will lubricate them without causing problems.
Better than a helicoil would be a 'Time Sert' made by a company called Wurth. There's plenty of car garages out there with them, have a ring about and tell them you'll take the risk of doing it with the head in place.
Posted 2 years ago # -
Jedi ... I've just thought. What size plug is it?
If it's a 10 or 12mm then you might just get away with re-tapping the next size up. You'd have to run a mixture of plugs but it's not the end of the world.
If it is 10 or 12 and you're not in a desperate hurry let me know as I've got taps, I could pop one in the post to you. If you need it in a hurry a tap should set you back about a tenner. You'll need either 12x1.25mm or 14x1.25mm.
Cheers Stuart
Posted 2 years ago # -
i think its time to get another vechicle
Posted 2 years ago # -
Helicoiling spark plug threads is not uncommon, difficult or expensive . . . once repaired it'll be as good as before . . . without doubt it'll be cheaper to fix it than replace it . . . I would never consider anything other than a helicoil repair and if you are not completely confident, you need to find someone who has done a few . . . local engineering shop would be the place to speak to . . . and find whoever overtightened the plugs last time and kive them a kick up the arse . . .
Fd
Posted 2 years ago # -
Tony,
You cant just tap it, has to be drilled.Just had a chat with my brother who is an aircraft engineer for flybe, before that he used to work on piston engined prop planes, he has done this job all the time.
They do it with the head on, but the exhaust removed so you can suck the swarf out as its produced, and then flush it out after, any tiny bit of dust on (if its alloy) apparently get burned up. He reckons most car places do it without removing anything and just suck the swarf out..
He was keen on doing it for you in return for some jedi training credit but he's in Cov and hasn't got time to go to MK...
Posted 2 years ago # -
Try this, available here, you never know, it can withstand the temperature & you could always run a separate earth to the plug if needed.
Cheers.
Posted 2 years ago # -
gunna try liquid metal
Posted 2 years ago # -
Check the heat rating, the above will take heat well.
Cheers.Posted 2 years ago # -
Put the end of the plug in a vice and very carefully squeeze it a bit so as to ovalise it a little thereby making it bigger across.
SB
Posted 2 years ago # -
2nd what strato said or fit a helicoil ,there must be someone on here who lives local and can fit a helicoil for you .
Posted 2 years ago #
Topic Closed
This topic has been closed to new replies.
