spark plug thread repair
 

the no.2 spark plug on my galaxy kept coming loose. i'd tighten it up and a week later it would be loose again. it would sometimes cause a bit of a misfire, but wasn't the end of the world.

anyway, yesterday morning i was driving along and the plug was blown out with an almighty bang. the plug itself being made of steel was still mint, but the thread in the aluminium cylinder head has been stripped.

i needed to get home from suffolk to sussex this morning, so effected what i thought would be a temporary repair at best, and 'glued' the plug in with

http://www.bostik.co.uk/diy/product/...poxy-Putty/125

http://www.bostik.co.uk/global_asset...ts/122_lge.jpg

to my surprise, i started it up this morning and it didn't just fire it straight back out again so i let it warm up a bit and went gently around the block a few times expecting it to pop out anytime, when it didn't i did a few loops of a dual carriageway and it survived so i set off for home driving like a vicar and it made it with no problems :banana:

anyway, i obviously can't leave it glued in like that as it is bound to pop out at sometime, and it makes servicing slightly inconvenient (on 160k miles now, with new plugs only 10k miles ago, so doesn't need them anytime soon) so i want to make a permanent repair somehow.

ideally i'd like to do something that doesn't involve removing the head, something like a helicoil.

can anyone recommend a kit, a garage local to horsham that they know of that does it, or if anyone local has a kit themselves that wouldn't mind helping out?

the helicoil seems like a reasonable option, but the wuerth time serts appear to be even better

http://www.wurth.co.uk/products/600601

Nick 160k has it had the chain done yet? if not id remove the head and helicoil it and replace the chain aswell.

Tbh i can't see that you have any other option as when the head is tapped oversize for the coil u will get swarf in the bore even with the old grease on tap trick.

Time serts are good but id not use them on a spark plug thread

Only a quick idea but my guess is your on "10mm" plug sizes at the moment (the smaller,more common of the two,could you not just go to the 14mm older size on just that cylinder?
Chances are the original hole+wear will be very close to the new size hole for the thread that you need and you can simply tap to that plug size.
I see no reason why it won't work,it is a little bit bodgerish but if you were that worried you could re drill/tap the rest to suit.
Not sure where you stand with the debris from doing it,ie swarf,my guess would be pulling the plugs and turning it over to throw the crap out could be an option as a magnet won't be much use really as non ferrous.

just looked on autodata and cam chain is an engine out job with over 7 hours book time and it isn't listed in the service schedule, so that's not happening :cry:

i've ordered a time-sert spark plug kit from ebay US. specifically designed for it, so will give it a go - if i can ever get the glued in one out! will just use grease and a hoover to collect the swarf and i have an endoscope that i can use to check i've got it all

Bit of ally swarf generally isnt the end of the world anyway TBH, will just end up sitting on top of the piston for a while then most of it will go out the exhaust, its unlikely to wreck the rings or anything, so certianly worth a go.

just crank the engine over before you fit the spark plug with a cloth to catch the bits

helicoiled many sparkplugs threads into alloy heads in the past with out removing the head, as said above grease the drillbit and tap, then turn over with the plugs out or high pressure air line and blow down the plug hole, this should clear the swafrf out.

cheeRS nick.

Nick why did you use the timesert?
I know there better as when i was at honda we used them on airbag stipped threads on body. as there solid in construction i just wondered why?
But hey i will be fine and as u have a scope there will be no issues :grin:

oh btw i wont b doing mine if the lamp has to come out:cry:

Paul

I've used time serts. There just the job.

time sert kit hasn't arrived from the states yet, but the spark plug popped out again this afternoon. haven't inspected it to see how exactly as it's a bit dark. will look at it once the kit arrives.

At least you don't have to worry about will or will not the glued plug come back out

exactly. don't know what else has come out or what is left in there though.

the states?? you could have got them from wurth in the uk mate.

yep, i saw that wuerth are the uk dealer for them.

done the job properly yesterday with a time-sert kit :banana:

that was a real pleasure of a job with a lovely quality tool. a very satisfying hours work.

i have some inserts left over, so if anyone wants it done in the future, give me a shout.