How Did This Happen? Mi16 Engine Problem

[Gavtrials 0]

Hello guys,

I sold my rebuilt 205 mi16 well over a year ago now to a friend,

Hes been driving it hard for well over a year now and the other day he phones me up with a problem.

He said the cars running really rough like its on 3 cylinders,

I poped round to take a look and the number 4 cylinder spark plug had blown out of the head, what was even more intresting was the actual spark plug outer body was still screwed into the head meaning the inner part of the plug seperated and looked like it had melted in some fashion.....Has anybody had this happen before or knows why it might have happened?

I took the head off to check everything else as atleast im going to have to drill out the rest of the plug in the head and everything seems good, all valves opening and closeing as should ect.....

Just would like to know what may have caused this?

[DrSarty 90 1 Cars]

Go look here: clicky

 

[DamirGTI 342]

Ask him if he's been removing/refitting the plugs , as sometimes the ceramic part of the plug cracks when undoing or (over)tightening the plug with the socket .. especially on heads with deep access spark plug holes (as on all 16v engines mostly..) ... and with the spark plugs with tapered seat (without the washer)

 

Damir

[Galifrey 1]

Ask him if he's been removing/refitting the plugs , as sometimes the ceramic part of the plug cracks when undoing or (over)tightening the plug with the socket .. especially on heads with deep access spark plug holes (as on all 16v engines mostly..) ... and with the spark plugs with tapered seat (without the washer)

 

Damir

 

Have seen this happen before with NGK plugs. The Ceramic wasnt properly rivetted into the plug body, and under high load, it just blew the ceramic insulator out of the plug body.

 

If you look at a new plug, and the body of the plug that blew its insulator, there will be a ring of metal around the new plug where it joins the insulator, in the blown plug this will be missing as it was rivetted too hard and the metal too thin.