Technical 1.2 8V spark plugs are falling out

[Pugglt Auld Jock]

If you have access to compressed air make sure the piston is at the bottom of its stroke and blow the glitter out. If you haven’t I would start the engine with the plug removed

I'm not trying to be "clever" but I'm wondering why you say with the piston at BDC? My inclination would be for it to be at, or near, TDC - which would make blowing it out, especially with a "long nose" blow gun much easier. Or am I not understanding something?

 

[koalar]

I'm not trying to be "clever" but I'm wondering why you say with the piston at BDC? My inclination would be for it to be at, or near, TDC - which would make blowing it out, especially with a "long nose" blow gun much easier. Or am I not understanding something?

Valves closed you don’t want to push any past the inlet valve

 

[Pugglt Auld Jock]

Valves closed

Ah, see what you mean - silly me! Sorry, had a disturbed night - due to late night with grandchildren last night and big lorry trying to take a shortcut through the estate very early this morning - His satnav didn't recognize it's a dead end - and he got stuck in the densely parked residents cars. Feeling a bit "shell shocked" right now

 

[koalar]

Ah, see what you mean - silly me! Sorry, had a disturbed night - due to late night with grandchildren last night and big lorry trying to take a shortcut through the estate very early this morning - His satnav didn't recognize it's a dead end - and he got stuck in the densely parked residents cars. Feeling a bit "shell shocked" right now

It easy when you know the answer. But it’s not that obvious

Mistakes = Experience = Wisdom



Using the right tools the job is the same head on or off. Things have moved on in the last 50 years or so.

Any glitter soon passed the exhaust valve finds its way to the CAT but it best to remove as much as possible

I couldn’t find a video how I would do it.

I wouldn’t use a ratchet
I would drop the piston down a bit
I would use a thinner lubricant like motor oil. We use to use paraffin machine tapping aluminium.

And so on.

But each to there own.

Getting a new head isn’t easy. There is at least 4 different 1.2 from 2003-2012. Then the replacement head is at least 10 years old and might not be much better unless it’s an expensive reconditioned one. Most heads on eBay will be from a scrap engine as they would have sold it as a compete engine

Taking the head off to do the job is just a waste of time unless you are changing the head gasket anyway

Take it to a machine shop they will either charge you to do it the same way (stepped tap) or to have it properly machined on a sine table would be very expensive.

I can’t emphasis enough the quality of the tap is important. Don’t use cheap rubbish.

 

[Pugglt Auld Jock]

I can’t emphasis enough the quality of the tap is important. Don’t use cheap rubbish.

A good policy to adopt for all tool purchases. A poor quality tool can cause more expense than you save!

 

[koalar]

Mine too.

I can't see any safe way of fixing this without removing the head.

Any kind of repair involving the plug threads that's done with ther head in-situ carries a risk of something hard/sharp that's not wanted ending up in the combustion chamber. If that happens and the engine is run, you'll be looking for a secondhand engine, not a secondhand head.

That’s what you’d expect

What happens is

The high pressure push any light bits out passed the exhaust valve

The only problem would be if you use the type with a tang and dropped that down. Even then a small magnet tapped to a cable tie should get it out.

 

[DaveMcT]

As all four are **ed, you really should consider pulling off the cylinder head and having them done professionally. The correct angle is VERY important and you really wont easily see what you are doing.

My MoT mechanic friend says its common for spark plugs to shake loose when they are not fully torqued down. They need to be tighter than you'd think but that risks them being over-tightened and stripped. However, all four stripped out suggests the person fitting them messed up. It happens.

Doing in place with grease on the tap will capture most of the swarfe, but what does fall into the cylinder will be sticky and will not easily vacuum out. I would set the piston and 1/2 stroke and do the job. Then use a curved tube to vacuum out the debris from the cylinder. Dropping the piston right down will reveal any remaining fragments the vacuum has not already captured. A £15 USB borescope camera on a smartphone will let you look inside and confirm its clean.

My motorbike had the same plugs as used on the Panda, but they were exposed to road crap and weather. They had to be removed every 12,000 miles or they would be so tight they risked breaking off. It used the wasted sparks system and being higher revving, the plugs pretty much shot (and rusty) so got replaced annually. I checked them after every winter and always used anti seize (yes I know it's not allowed) but without that help. they'd have never come out again.

 

[Pugglt Auld Jock]

The only problem would be if you use the type with a tang and dropped that down. Even then a small magnet tapped to a cable tie should get it out.

I thought these wire type inserts were made from a type of stainless steel - so wouldn't be magnetic? However I just went and tried it out on one of the inserts in my kit and they are magnetic! Every day's a learning day!

 

[Pugglt Auld Jock]

I can’t emphasis enough the quality of the tap is important. Don’t use cheap rubbish.

Learned that lesson many years ago when I bought a cheap set of high carbon steel taps - really looked the business but they were almost as brittle as glass. Proper tool steel ones (Dormer or similar) from then on for me. Very much the same story with twist drills, if it's cheap it'll almost certainly snap at the first opportunity and leave you with a much bigger problem because they're still pretty much impossible to drill.

 

[vexorg]

I thought these wire type inserts were made from a type of stainless steel - so wouldn't be magnetic?

I remember some grades of stainless can be magnetic. Or they could be made from cheap chinese stainless that is always oddly magnetic

 

[koalar]

I remember some grades of stainless can be magnetic. Or they could be made from cheap chinese stainless that is always oddly magnetic

Correct

It’s an alloy mixture. Some is magnetic and some isn’t

 

[jrkitching]

Magnetic properties of ferritic, martensitic and duplex stainless steels – British Stainless Steel Association

bssa.org.uk

 

[koalar]

My MoT mechanic friend says its common for spark plugs to shake loose when they are not fully torqued down.

As I said earlier

If they were loose and you keep driving

The alternate vacuum and high pressure will vibrate the plug up and down like a pneumatic jack hammer until they smash the threads off and blow out. It’s very common on certain cars

Which may or may not of happened in this case. We will have to wait until the original poster has assessed the situation

 

[koalar]

Learned that lesson many years ago when I bought a cheap set of high carbon steel taps - really looked the business but they were almost as brittle as glass. Proper tool steel ones (Dormer or similar) from then on for me. Very much the same story with twist drills, if it's cheap it'll almost certainly snap at the first opportunity and leave you with a much bigger problem because they're still pretty much impossible to drill.

Correct

Getting off topic but Aldi taps are rubbish. Unfortunately unless you know what a proper tap cuts like your likely to be in trouble before you know it.


Gone are the days when I have access to a spark eroder which makes removing broken taps and drills a trivial task.

Better to buy quality and do the job correctly first time

 

[bax]

I did the similar job some 100.000km ago nearly on new engine, 10yeas ago.
Reason, some bad workshop screw sparks out of alignment, ruined two threads.

Other more experienced workshop had easy solution:

1. Try to clean threads with threading tool (he put tool in grease, to pick aluminum dirt)
2. If 1. failed second option was to expand hole, thread new threads, and insert small sleeve (he had specific tool for that operation and sleeves) as "man in the middle"

Most important, he was always using grease on tools, to pick aluminum dirt from head, and he also told me one more thing (MOST if not all aluminum dirt in chamber will melt in mili-seconds when engine starts, so there is no need to be worried about additional damage to engine.... )

After that I am still happily riding this car (my relative to be honest )

 

[DaveMcT]

I've got a set of Aldi taps that were worth the money just for the handles and great for cleaning threads. They are second taper so not suitable for everything but I've never broken one and they must be at least 10 years old. I also have some posh M8 and M10 fine that got used on the Suzuki but they all feel much the same in use. I am fussy so would notice the difference.

The odd aluminium shaving in the cylinder is unlikely to do any harm but very unlikely to melt. Personally I would rather suck them out with a vacuum its easy enough through "normal" side spark plug holes. It would be different with the small plugs used on 16V engines.

 

[The Panda Nut]

As we are all saying, this is not a job for the inexperienced and/or faint hearted. Without some considerable experience and all the correct kit, it's very likely to end in tears.

I was also, thinking laterally, that with only 20,000 miles on it and if the rest of the vehicle is in well above average condition, it could be worth spending the money involved in taking the head off. I say this because, although not a big problem, we all know the cylinder head gaskets on these can fail if either the engine has been very hot at some time or they can fail simply due to age deterioration - often blowing on No1 cylinder in my experience. If the rest of the vehicle warrants it you could be killing two birds with one stone by repairing the plug thread (and it will give you the opportunity to closely examine the other 3) and fitting a new head gasket on reassembly. The problem for Diamond will be if he can't do this for himself as labour cost will be considerable. However he says in his first post - at the top of the thread - that he's used helicoils before so if he does all the labour himself I think taking the head off, checking it very carefully, including the flatness of the face, and doing the repair on the bench if it all checks out would be the way to go. Good opportunity to put a new timing belt on during the rebuild too if it needs one.

Not quite the same problem, but I cross threaded one a while back. My local man fixed this and charged 1 hour which seems pretty reasonable to me. Torque figure he quoted me was 18 somethings which is not a lot. If they have all been over done and the threads stripped Its a head off job I agree. New plugs havbe compressible washers so trying new plugs might help?

 

[jrkitching]

New plugs have compressible washers so trying new plugs might help?

It won't help once the threads have been damaged, but fitting a new washer if you remove and replace an existing plug is an excellent idea.

 

[jrkitching]

Torque figure he quoted me was 18 somethings which is not a lot.

It isn't. Most amateur 1/2" drive torque wrenches aren't much use at this sort of setting.

Whenever I've removed plugs from a new car for the first time, I've noticed how little effort was needed to get them moving. Folks often seriously overtighten plugs, which stretches the threads on both the plugs and the head. The same applies to wheel bolts (though obviously the torque settings are much higher).

Also when using any torque wrench it's important to tighten in one continuous motion, particularly when you're getting close to the final setting. This is because the torque needed to start a threaded component turning is greater than the torque needed once it's moving. If you stop and restart, the wrench may 'click' before restarting if the starting torque has been reached, which risks leaving the fastening insufficiently tightened.

In days past, it was common practice to retorque the head bolts a few hundred miles after reassembling an engine. This is the reason why you were always told to first undo them slightly before retightening.

 

[Pugglt Auld Jock]

I've got a set of Aldi taps that were worth the money just for the handles and great for cleaning threads. They are second taper so not suitable for everything but I've never broken one and they must be at least 10 years old. I also have some posh M8 and M10 fine that got used on the Suzuki but they all feel much the same in use. I am fussy so would notice the difference.

The odd aluminium shaving in the cylinder is unlikely to do any harm but very unlikely to melt. Personally I would rather suck them out with a vacuum its easy enough through "normal" side spark plug holes. It would be different with the small plugs used on 16V engines.

A set like that - M3x0.5 to M12x1.75 &, strangely? one off 1/8th NPT - taps and dies, turned up at either Aldi, Lidl,or maybe it was one of the market stalls down in Salisbury (where I tend to hang out when we're down there visiting my daughter and she and Mum have gone shopping) compared with my better quality stuff they are not great but, as Dave says above, they are very good for cleaning up slightly damaged or dirty threads. I do find the sizing is slightly random with one size being slightly tight on the workpiece and another being loose. The dies are solid too so you can't squeeze or expand them to get a better fit. Good enough considering the peanuts I payed for them but I don't use them to cut new threads.