If the worst comes to it, it seems there is also a "Big-Sert" designed to repair already-repaired holes!

Anyway, I put platinum plugs in this time so hopefully I won't have to worry about that for a while.

Cool,

I see what you mean Will, I do like their design, a lot more substantial than good old Heli-coils

Peter

Just when I thought it was safe, the saga continues. Changed the plugs today as the (admittedly cheap) copper ones we put in a year ago were beginning to misfire at high revs when running on LPG. The plug in question was very stiff to remove and brought the timesert with it. The timesert's threads were covered in brown goo (presumably threadlock) and slightly burred at the end. I believe this burring was by design: a timesert is essentially a helicoil with a slight thickening at the end so that when a special tool is inserted, they splay out fractionally and lock themselves into the head - or so the theory goes. It doesn't seem to have worked in my case.

Was taken back to the garage that originally did the work and they refitted a new timesert. It seems to be holding up. However, I have been advised that for the timesert to have come out at all, it is likely that the head is cracked, and that the new timesert will probably go the same way.

Cost of a new head, anyone?

One other thing I noticed is that when the put the original timesert in, the plug (and coil pack) always stood slightly higher than the other three. Now it stands even higher still - probably nearly 10mm. Is this normal?

Sounds like they've fitted the wrong length timesert (too long ).

Edited 20 August, 201015 yr by vwcabriolet1971

Hi,

I had a plug blow out on a n 405 GTX I had years ago. Sounds like a tank running on 3 cylinder without the last plug in!

As I understand it the only fix (apart form a new head) is to use a sleeve (helicoil). I suspect that the plug blew because I had a new head gasket fitted (as a precaution believe it or not) an did NOT use new (stretch) head bolts. Think the Octy may have the same. Be sure to use new bolts when refitting. It may have also been that the plug in question was cross threaded or overtightened at some point. But if that was the case it lasted a while as I was in Poland at the time and the car got me back to the UK and back to Poland about 2000 miles.

If you do need a new head it has to come off anyway to either fit it or put in the helicoil as to put it in without taking the head off to inspect what was down the cylinder would not be a good idea.

Hope you get it sorted.