Spark plug hole STRIPPED - HELP

**Tee5alive** · Tuesday 26th April 2016, 10:51

Today is the first chance Ive had to look at the car after she went a bit wonky on the way back from Devon.

On the way back up the M5/M4 - the engine note changed slightly. So I stopped and had a quick look round the engine in the services. Seeing nothing obvious I carried on until about 10 miles from home the check engine light came on occasionally. This was also accompanied by a 'chuffing' sound - so Im thinking AIR LEAK. I managed to get off the motorway and limp home.

On initial investigation I found the number 2 spark plug had shaken loose and damaged the coil pack nose, so I ordered new plugs and a coil pack. The other plugs were all tight and I was planning to change the plugs this weekend had she been ok!!

Today however, I went out to change all the plugs and replace the loose plug. To my horror looking down the plug tube the hole looked 'different' to the others. It appears the plug has 'ground away' the plug threads inside the head due to vibration??

Now my question is (as the car only cost me £800) - is it worth saving? It is my daily driver and had been reliable UNTIL NOW.

1) Can the head be helicoiled in situ cheaply?
2) OR will the head have to come off leading to £££££££'s in repairs - (more than this thing is worth) and more than I have in the bank?

My other car - the C70 is also now dead and running on only 4 cylinders, previous to her going into storage she was running fine. I need to get up and down to Torquay every week and the options are now looking dire. I currently have a rental car which I cannot continue due to cost.

any ideas please? DESPERATE

**960kg** · Tuesday 26th April 2016, 11:23

The only thing i can suggest seeing as you have only undone the plug and removed it is to get an old plug and cut slots up the side of the thread with a hacksaw.

Gently tap in the protected threaded part so that it is very slightly tapered.

When putting in the plug hole turn it backwards,anticlockwise, until you feel a click and the plug will drop down a thread and then you know it is not cross threaded.

Then gently turn in half a turn and back out quarter of a turn until the plug is seated then remove.

See if there is much alloy crap on the tapered plug to weigh up the situation and gently put your new plug in.

When seated a quarter of a turn is all that is recommended for tightness if it does not hold.........then you have trouble!

I have always given my plugs a squirt of WD40 on the thread when applying they go in more smoothly on the alloy.

**Tee5alive** · Tuesday 26th April 2016, 12:42

thanks mate. The plug DOES screw in but there's barely 3 rows of threads left so the pressure will blow it out! The rest of the plug hole is completely SMOOTH like its been reamed out on a machine!

Obviously needs an oversize helicoil fitted. I am not sure whether to throw any more money at this car or let her go with dignity! A head strip and rebuild OUTDOORS is no fun - no garage

The only good news is after spending all morning on my C70 thats in storage, she may be a runner after changing a coil pack!

**Orca2** · Tuesday 26th April 2016, 13:58

I dont suppose there is a slightly larger diameter plug you could use? Then tap a new thread in situ. Presumably there will be some car that uses a larger diameter thread but with the correct or similar plug length.

I always have a smear of coppaslip in my plugs just in case . Yeah I know, closing the stable after the horse has bolted.

I hope you can get a solution its a shame to junk the car for such a minor problem.

**Tee5alive** · Tuesday 26th April 2016, 14:12

Thanks Orca - brilliant idea!! Who knows what the thread pitch is for spark plugs???

Im thinking if I can get hold of just a HEAD will it be cheaper than a ream and helicoil by a machine shop ALSO stronger?

DOES ANYONE HAVE A SPARE HEAD GOING PLEASE??

UPDATE: after changing the coil pack I thought was duff on my C70 shes now running - so taking her off SORN and back on the road! V70 going to storage pending rebuild.

**Tee5alive** · Tuesday 26th April 2016, 14:59

http://www.xxrtools.co.uk/14mm-spark...nsert-kit.html

Hmmmmm interesting - ordered one to see if its any good. In theory as long as I vacuum out any swarf from the cylinder it could save a strip down?

opinions please Volvo experts?

Shes done 11,000 faultless miles since I bought and repaired her 6 months ago for the Torquay run so I think shes worth another try!!

**stribo** · Tuesday 26th April 2016, 17:56

I had a spark plug fire out of my C70, and take the thread with it, got a recommendation for a bloke who could put an insert in, so I could still use original plugs, think it cost about £100. That was 2 years ago, and not had a problem with it since. If you want I'll dig out his phone number.

**Tee5alive** · Wednesday 27th April 2016, 02:49

NICE ONE cheers Stribo - that's TWO beers I owe you now!!

**Tim Williams** · Wednesday 27th April 2016, 08:07

Most 2.3 ME7 spark plugs that work loose are as a result of the cylinder heads cracking between the spark plug threads and the exhaust valve seats. A Thread Insert is far better than a Helicoil.

**htomi** · Wednesday 27th April 2016, 08:21

+1 for Thread insert. Friend of mine had the same issue. Cylinder 3, coil destroyed, spark plug was nearly out. Local shop did the job for less than 100€. After 2 years still holding fine.

**stribo** · Wednesday 27th April 2016, 18:42

Originally Posted by Tee5alive

NICE ONE cheers Stribo - that's TWO beers I owe you now!!

http://www.thethreadwizard.co.uk/index.php i.i.r.c.his name's Barney.

**Tee5alive** · Wednesday 27th April 2016, 20:51

Originally Posted by stribo

http://www.thethreadwizard.co.uk/index.php i.i.r.c.his name's Barney.

Nice one mate thanks, shes going into the yard now and the C70's back on duty!

**Tee5alive** · Thursday 12th May 2016, 14:56

UPDATE

Luckily ive found a guy closer to me - as the chap you recommended Stribo - wont come as far as Wokingham

£102 + VAT

**Wobbly Dave** · Thursday 12th May 2016, 15:21

I have a spare ME7 head if you still need one? I bought it because I thought the SSB had done her own head in - but we are still good to go on that front.

If your own cylinder head cannot be rescued then I can help out.

**Tee5alive** · Friday 13th May 2016, 19:54

Thank you so much Dave will let you know ��

**Tee5alive** · Saturday 9th July 2016, 12:53

The nice man arrived yesterday and re-threaded my hole (ooo er missus) so to speak!

Fitted new plugs (battery dead so had to leave the booster pack on to get it above 0 volts), removed that and she jump started straight off, purring now like a kitten in the sun!

ANOTHER BONUS. driving Mrs Turbo around I have now 'converted her' to Volvos! (previously a Merc nut - aaaargh any colour AS LONG AS ITS SILVER!!!) so the V70 R now looks like a goer!

smiles all round

so back to the weekly Torquay run for the big dog!