Wheres the F$#K has the end of my spark plugs gone!!!???

[AE86fan]

Took the car for a squirt after putting the turbo manifold back on and found it to be running real rough once it warmed up.

Found it wasnt running properly on 2 cylinders, pulled out those 2 spark plugs and F#$K ME the end of the spark plugs were completely blown off, all that was left was the metal rod up the centre. Amazing thing was when it was cold it was running sweet!!

With the 4agte Manifold Im using I had to take the CAS out to get the manifold back on, after a bit of trial and error I got the CAS back in the right spot but not before I must have had the engine running massive advance which Im guessing rooted the plugs (platnium nikko denso).

I have done a compression test and everything looks alright there, now my biggest worry is should I just throw some new plugs in it and hope for the best.....or should I be pulling the head off to inspect for piston/valve damage and potentially damage to the turbine??

[Burning Angel]

like this?


or was it all burnt and melted looking with ground electrode missing.

im gonna say you had a pretty serious case of detonation, that'll fry plugs in no time.

i wouldnt bother with platinums either, mainly 'cuz theyre real expensive to blow up. standard densos or ngk would be fine.

[Rick]

[AE86fan]

Looks like the 'pre-ignition' one in the photo just a bit worse, with no ceramic stuff left at all on one of them and a small bit of electrode.

Burning Angel, How did you manage to snap that plug in two??

[Burning Angel]

I didn't snap it, it was out of a customers car.
At first i thought he'd over tightened it but if you look at the fracture theres no twisting.
he said he was driving along and there was a big bang, plug had gone through the sparkplug cover and made a dint in the bonnet.

[BlakeNZ]

Almost certainly a severe case of detonation. When it is this bad, you normally have ring land damage or even melted a hole in the piston. So you are fortunate the compression test came up well. Broken bits will have been blown out the exhaust valves by now i reckon, so put in some normal plugs,and sort out your timing issues. Platinum plugs are more prone to detonation(IMHO) due to the tip retaining heat.