Spark plug nightmare

[hywelhightop]

Got a potential nightmare on my hands.

As I was driving normally the other day, my 1989 watercooled 1.9 started chugging like a tractor and slowed up a bit. I pulled over to have a look and the spark plug under the air filter had popped out. No probs I thought, however the thread on the plug is battered and as it was pushed out of the head it has wrecked the thread on the head. It wont screw in and hold at all. I know I need to take the head off at some point and get it sorted properly but does anyone know of a stop gap solution to get me through the summer.


Please Help

Gareth

[Mocki]

i dont think there is a solution thats sensible

bodging it will always be on your mind and you will not trust it.

replace the head now, before summer gets here ( if it comes) is my opinion.*









*other opinions are available im sure!

[sarran1955]

Hello,

Depending on how much access you can make for yourself, and hoping that there is still some thread metal left in the spark plug hole.....

The proper way to do this is to helicoil it with genuine helicoils. I have the tooling for this, and would do it by post, or you can get an engineering shop locally....don't forget that once you have gone this far you might as well get both heads off, 4 helicoils, fit new valve guides, exhaust valves, and valve stem oil seals. Bits are not dear, but there is a fair bit of work.

Now for the 'get you out of the sh*t solution.

Take an old spark plug of the right length and remove the electrode. Now cut vertically down with a hacksaw or a 1.6 mm stainless cutting disc, offset to avoid the central electrode, two thirds of the way down through the thread. Blow clean with compressed air, and make sure there are no loose bits of ceramic. The idea is to rethread this plug into the damaged hole with a '2 steps forward 1 step back, movement. If you have fine valve grinding paste put some on the cut plug thread , this will help.

Wind the plug out, clean the thread with thinners on a cotton bud, blow everything clean with compressed air.

Now try the new plug. It would be a good idea to know how many turns needed to lock the thread. If the plug nips up ok, then wind it back out, use a smear of copperslip grease and Hey Presto.

A straight bit of rubber tube/hose over the end of the plug can be helpful to get it started in the thread.

If the plug still feels rocky, then use Bearing locking compound. I use BERNER HBL 60, in a little yellow bottle. Clean everything with acetone, apply product, and put plug straight in. This product WILL destroy what's left of your thread when you take the plug out, so now you know how long you've got before dropping the heads.

Fingers crossed...

Cordialement,

[hywelhightop]

Thanks for the replies,

I'm still a bit unsure what to do. I would really like to take the head of, get it helicoiled and then job done, but for that I reckon I'll have to take the engine out and then may aswell do a whole lot on the engine - and to be honest I hav'nt really got the time.

Does any one reckon I could take the head off with the engine in place? It says in good old Haynes that it's possible but not advisable?

I love my VW but I just want to get to big bang in 2 weeks time.

[jason k]

to get yourself out of the "pooh".e do what sarran says as a temporary stop gap. its easier than pulling the head off for now.

have you tried running a tap down the thread?

putting a picture or two up may help us assist you better

[ghost123uk]

Taking the head off sometimes / often results in a whole new can of worms, broken head and exhaust studs, needing to replace liner "O" rings etc. Unless the head to block seal is dodgy or there is another GOOD reason to take it / them off I personally would avoid that route.

The good news is that I had this happen a year or 3 ago and my local T25 capable garage Helicoiled in situ. I was concerned about how they would get on, and also about swarfe but they assured me it would be a pretty routine job for them and so far it has proved fine, including at least 1 plug change since They charged me £40

[hywelhightop]

Thanks for all of the help that people have posted. Steve at Gassure has got in touch and let me know that he can hellicoil it in situ so I'm going to nurse it to chester and get it done.

Thanks again