My 172 HT Lead explosion!

[Wadsley]

Well just as im running low on cash and put the car up for sale, this happens...

Was off to work in the car this morning, pulling off on a steep hill and i heard a bang and then the car sounded like a tank and had lost compression and the engine management light came on, i still drove it back home (1.5 miles) and when i came back to check it later on found that the end of the ht lead had exploded at the plug end and the plug had come up? What could have caused this to happen and what damage should i expect to find, and what to do about fixing it? Just simply replace the ht lead and plug, which i should imagine needs re tapping as its been fired up. I will have a better look tomorrow but any help and guidance would be appreciated.

[Justin..]

worst case scenario - Plug has been blown out of the head.

[col]

cross threaded plug ,weaknd alloy thread ..........blew plug out


Fix ....helicol....re thread.........(have i spelt that right?)..........

..
.....poss head off..... :( .......You might get away with retapping thread?

[Rudders16v]

I had the exact same thing on my old ph1 172 when I had it up for sale. Just needed a new plug and Heli-Coil and put some second-hand leads on. Cost me about £30 for labour / heli-coil and another £20ish quid for leads/plug so might not be too bad.

[Wadsley]

Thanks for all your replies it does need re-tapping but glad to hear that there's nothing else to worry about, cheers.

[schakal]

thats absolutely fcuking shocking to be honest


so whats wrong with these 1 7 poos than ? is it faulty fitted
plug or the strength of the plug hole threads to blame ?

[Justin..]

plug could have been cross threaded or over tightened, the heads only ally so will strip easy