well my 240 has built up a appetite for spark plugs lately. I discovered the sputtering problem it was my spark plug chewed up from who knows what it looked bad. so we replaced the plugs i took it around the block and the problem started again. i checked the #3 plug which was the one that had the problem before. it was fine so i checked the #4 and the inside ceramic parts and the cord where sucked out and rattling around in the cylinder. the plug was hollow ill post some pics later so i need a motor now woohoo anyone else have this problem? cause it may have been the spark plug just falling apart. has this happened to anyone?

 

The first picture will be of what plugs 3 & 4 looked liked. We recently replaced them when we rebuilt the head and timing chain kit install. The car ran fine for a while and then started running extremely rough. The timing was good, vacum lines ok, pulled plugs (maybe 500 miles on them) and found 3 & 4 in this condition. (You can click on a picture to see a larger version.)
They looked like they were beaten closed!

Changed plugs and ran it for a little while and the following happened!
This is/was plug #3

This was plug #4..The entire diode (I think its called) ceramic center with post is GONE sucked right into the piston and who knows where else!

 

never seen that b4 did it damage the engine ne if so i would call up the spark plug company

 

wth, never seen this before! Your pistons must be hitting them

 

yea that could be it. but i done some thinking and my dad reminded me of our previous shaveing of the head, we shaved the head .008 around december to balance it out. but i drove it for a while with no problems like that and this just all the sudden started happening. It sucks i drive it around town go home and have to change plugs. So next time im going to try putting another spacer on the plug so it wont be so long and see what happens. It's mostly the #4 plug doing this the #3 does ocasionally and the #1 and 2 dont have no problems. I'll keep yall updated.

 

yeah its happened to me. my spark plug ****ed in cylinder #1 and parts of the wire and plug broke and all the parts are rattleing around in cylinder #1 but I got lucky after I checked that and changed my plugs and wires and then I took my oil pan off. cuz i was hopein maybe some of parts fell down into the pan. and they did. so now my engine is fine and it doesn't rattle anymore.

 

i would think if the pistn were smackin the spark plug the case would be bent as well not just the center of the sparkplug being damaged... would be hard for the piston to hit the bottem and do no damage to the body or the threads while causing the ceramic and the electroid to look like that...
as far as the second one does... the plugs are massed produced and there is always that chance that it was not assembeled right... i would contact the manufaturer of the plugs and send them both the pics of the plugs you removed the one that is hollow and any plugs you remove frm your motor...
the reason i say this is... they make a living out of making and testing sparkplugs as well as other parts and this could be a tech issue that they either do or do not know about... who knows you might just get new /better plugs out of them...

 

could very well also have something to do with the shaving of the head! maybe carbon deposits on the pistons now, awhile after you rebuilt it, hitting the spark plugs cause of the close tolerances due to the shaved head. you could experiment with colder plugs (should make the whole plug further inside the head) but i would also be worried about the rest of the motor as obviously somethings not right!
-sage

 

http://www.gnttype.org/techarea/engine/plugs.html

Have you looked there? I just found it..maybe it can tell you what happened...