sparkplug getting smashed

[capman86]

I swapped an f20a sohc in my 93 cb7 motor is super clean and everything seems original timing belt and all that. My point is recently I was going through some gears and the engine just misfires all crazy and then starts idling like im running off three cylinders I got back home checked the timing real quick and the light was flickering all crazy so I pulled the plugs and the number one plug was smashed just enough to close the gap. The plugs were iridium (or how ever you spell it) so no gaping. I had some extra plugs so I put a new one in and everything was fine for about 4days then it happen again only this time it broke the plug. Like I was saying before it looks all original so I don’t think the head was milled or anything or the head gasket was changed. What could cause this what can I do to prevent it my super sure I have the right plugs cuz I’ve messed with the f20 f22 allot but im just looking for some suggestions


thanks

[bruno8747]

Whats the model number on both of the plugs?

[LinX]

if the engine is stock then are you sure that you're running the right plugs?

[wed3k]

physical contact with the plug is a no bueno so i wonder what the hell might it be touching?

[jhondayaaj]

physical contact with the plug is a no bueno so i wonder what the hell might it be touching?

obviously the piston I assume. double check the threads and make sure that it isn't going too far down.

[ACC0RD22]

obviously the piston I assume. double check the threads and make sure that it isn't going too far down.

the plugs dont stick out THAT far, any piston to plug contact would also bang the valves up pretty good, so id assume its something else.

[10thcb7]

step colder ? My suggestion. NGK has the only numbers that go up as they get colder . I think thats how it works . Either way any one at the autostore can figure out which way to count to go colder. thats my .02

[Turbo Dave]

step colder ? My suggestion. NGK has the only numbers that go up as they get colder . I think thats how it works . Either way any one at the autostore can figure out which way to count to go colder. thats my .02

thats my guess too, the piston couldn't hit the spark plug without losing complete compression in that cylinder.

[capman86]

i changed some guys plugs in an accord one gen up not sure the year; with vtec, and they were those four prong bosh platium ones they also smashed all four prongs

I had this engine on my 90 cb7 for about 7000 miles with the same plugs then i took the engine and swaped it to a 93 cb7 with a cleaner body now about 2000 miles after the swap im going through plugs, the only thing i notice different now is that there is a little trace of oil on the plugs when i remove then

it is the hottest weather i have ever drove the car in thow?!@#%%&

the car has i/h/e prelude mani no ps or ac lighetn fw cluch walbro 255 also not that any of that shit matters

[newtuner7]

the only reason i can see the spark plug getting smashed is if you have the incorrect ones in there