spark plug meets pistion? the piston won

[yotawheeler]

ok, i was doing some work on my cruiser and i took one of the spark plugs off and it was smashed to s***, it looked like somone put it in a vice and beat it with a hammer....does anybody know what this could be caused by? im guessing somthing in the cylander but im not sure because i bought some new plugs, started it up and then checked the plugs and the new plugs were fine....has this happened to anybody else? anyways i dont know what the problem is...my engine isnt running properly right now (obviously) but its not making any noises like the bottom end is screwed...so i really dont know and the guy thats helping me is just as puzzled. any input would be appreciated

thanks guys
Guy

 

[Poser]

...my engine isnt running properly right now (obviously)

Expand on this, just a bit please....


What engine? 6 or V8 or ???



Have you removed the rocker cover to see if all the valves and rockers are working like they should?


You could very well have dropped a valve.

 

[Pin_Head]

If the beat up spark plug is the same type as the others, then some foreign object was loose in the combustion chamber and that can't be good, considering that the piston is aluminum and softer than the spark plug. You can take a peek with a flash light with the piston at TDC, but I'm betting that it won't be pretty. Either something fell into the intake or something broke off to do this kind of damage.

You might also consider doing a compression test. If the compression is OK, you might have dodged a bullet.

 

[nuclearlemon]

mine was a timing issue....granted it was a v8, but the distibutor was shot and threw the timing off and a piston kissed the plug...not a pretty kiss either

 

[yotawheeler]

ok sorry about that. its a '74 with the F strait 6 engine. it was running on 4 and then when i put new plugs in the cylanders that i was having trouble with the pentronix kit it was running on 6 and with no damage to the plugs. i know my valves need to be ajusted and thats slated for tommorow hopfully it will fix the plug issue? ill check and see if I can check the timing as well tommorow....i might check compression as well. thanks for all the advice and ill check on as much of it as i can tommorow

 

[Mark W]

mine was a timing issue....granted it was a v8, but the distibutor was shot and threw the timing off and a piston kissed the plug...not a pretty kiss either

Distributor timing won't make the piston hit anything. And no sort of
misadjustment can make a piston hit a spark plug.

Your problem, and the one referenced in the orignial post here is was almost certainly timing related though. Timing that is too advanced can lead to detonation and that WILL shatter spark, mash, hammer and otherwise destroy spark plugs. Rings and pistons too.


Mark...

 

[largenfirm]

Another possibility is using the wrong plug - I did this in a '64 Dodge 1/2 ton long bed, once.

Bought a set of plugs at NAPA, didn't notice that one was different, put them in, started it up, and drove it for a couple of weeks. Wasn't running well, so I decided to look at the plugs - one wouldn't come out.

Had one hell of a time getting that plug out - it was peened over on the end by the piston - had to pop the head, and clean it up with a die grinder before the plug would unscrew.

Man, that was a crappy truck...

Kirk

 

[Shawn Russell]

The only way the piston is going to hit the plug, is the plug is too long (ie wrong plug) or you broke a rod... As said before detonation can kill the plug, or something else is in the chamber.

Shawn

 

[yotawheeler]

ok thanks guys....what really puzzled me is that when i put the new plugs in they were undamaged after running it for about 10 or 15 min. ill try to ajust my timing today and valves and ill keep you guys posted thanks for the advice

Guy

 

[Diesel42]

i agree that the stroke of the crank,rods,pistons in relation to the head doesn't change. An incorrect plug maybe, but it would have been notices on the first start if a longer plug was installed. I see people using a optical tool which has a length of tube that could be placed easily into the cylinder through the sparkplug hole for examination. Maybe a buddy or contact of yours has one. Seems i've seen these advertised at harber frieght . Otherwise i would be inclined to pull that head for inspection. I just am not that fond of hoping things of that nature will just go away,you know. FInd a problem earlier it might not be that big of deal. Alot of info can come out of pulled that head. While it's off, rebuild it, might save alot of grief. Good luck, keep us posted.

 

[Nomis]

I see people using a optical tool which has a length of tube that could be placed easily into the cylinder through the sparkplug hole for examination. Maybe a buddy or contact of yours has one. Seems i've seen these advertised at harber frieght . .

Called a "bore-scope". But you should be able to see most of the piston top through the plug hole - if you get it near TDC.

 

[yotawheeler]

ok....well i just got back from camping and my plugs seem to be allright. i know that pulling the head off and re-building would be the best thing to do but i just cant pull that much coin outta my pocket right now, especially since i plan on a diesel swap next year. i think it could have been somthing to do with my valves like poser sugested, i had quite a few that were pretty messed but i have them fixed now. thanks for all the help and advice.

cheers
Guy

 

[Mr. Toad]

ok....well i just got back from camping and my plugs seem to be allright. i know that pulling the head off and re-building would be the best thing to do but i just cant pull that much coin outta my pocket right now, especially since i plan on a diesel swap next year. i think it could have been somthing to do with my valves like poser sugested, i had quite a few that were pretty messed but i have them fixed now. thanks for all the help and advice.

cheers
Guy