Damaged spark plug thread

Depends on head design. On some, a valve seat insert is so close to the thread the tap can dislodge it.

Well eventually it'll die. It depends how long you're going to keep it.

Probably wise

Unless you're very fussy, not normally. Your local motorcycle dealers more likely to do it though, they're normally a lot more practised with helicoils & it's not hideously expensive.

An engine reconditioning mob may have the kit to make a thread repair. Or ask at Repco or Supercheap who does this type of repair.

Or buy yourself a repair kit comes with Tap and inserts. Just use lots a grease to collect the swath.

Kits have a stepped tap which starts and lines up in the original size then makes a large thread which the insert is screwed in. Easy if you have the correct tap and most likely cheaper than getting someone to do the job.

Where are you located?? besides Australia?? or send me an email.

Thanks. I've needed to tap holes before for oversize studs or for helicoils, but I think I'll leave tapping into a combustion chamber to someone who knows exactly what they're doing.

I'm in Canberra. Being inland Australia, the car's in as-new condition at a mere 13 years old. No salt and not much moisture, so absolutely no rust. I've looked in disbelief at the corrosion on near-new cars in photos from the UK.

I fitted iridium plugs, so it'll likely be another 5 years before they need replacing. I might just wait until then.

John

I'm up the road a bit and you could have borrowed mine.

But CBC Australia ?57 Kembla St, Fyshwick ACT 2609(02) 6280 4288? Have the kits.

• Spark plug kits have pilot nose taps for accurate self alignment eliminating the need for drilling

Should work out cheaper than the cost of those plugs. Whats more they come with 5 inserts you can do the lot.

Thanks Rob, and others who've replied.

I'm tempted to have a go, and at least have a kit on hand if I decide to remove the spark plug here at home.

John

Wind the piston down below TDC, really pack some grease down the spark plug hole, fit the helicoil, remove the tang with long nose pliers. wind piston to TDC removing swarf & tang ( sods law) in the process, crank engine without spark plug to remove grease & bobs your uncle.

Ah, I was wondering about the tang. Unfortunately the spark plug hole is deeply recessed, so it might be quite a fishing expedition getting it out.

Thanks for the advice - it's just the detail I need to know.

John

the way we always took the tang off was a twist with long nose pliers, the recommended way is a swift tap with a drift, but the pliers work well.

Not on any engine I've ever seen.

And what remains isn't going to do much damage, being aluminium, as it will wash and blow out the exhaust.

IME if the piston is at bdc when grease is put in through the plug hole and then the piston is brought up on the forward stroke until the grease appears at the base of the thread all swarf is ejected on the remaining travel of the stroke. The rapid spinning of engine prior to putting the plug back in is to eject remnants of grease.

AJH

Seen it in motorcycle engines

Either Rover V-8 or Jag XK, can't remember. But I've only read about it.