So this happened today

[FastCraig]

I was driving down a rural 2 lane road in my Monte. Just cruising. I caught up with an 18 wheeler and was looking for an opportunity to pass. When I was able to get around the truck I gave about 4/5th throttle and the Monte was pulling hard and then, all of a sudden, it lost some power and started missing. I pulled over, shut it off and popped the hood. No spark plug wires were loose and I didn't see a vacuum line loose. I started it up and headed home so I could do a more thorough inspection. I found nothing wrong externally so I pulled the plugs to see if one was fouled or loose. The number 3 spark plug apparently made some contact. I don't think anything was broken but this is scary. I got lucky I guess.

 

[fleming442]

OOF! New engine?

 

[FastCraig]

No. It has 15K on it. It was recently (1500K) taken apart for a head leak. A head gasket partially failed. I did have the heads shaved just enough to insure they were true. Guess I'll have to go with a thicker gasket.

 

[lilbowtie]

That raises some questions !

 

[Clarmo]

If everything checks out OK.
Get some NGK R5671-7 plugs, they don't have the projected tip.

 

[WanaBa442]

Got a borescope? I'd take a looksee before I tore it all apart...
May have swallowed something, or busted a rock hard piece of carbon loose.
If you're thinking your pee-stone came up enough to ding a plug, you've likely got bigger issues..

 

[FastCraig]

Got a borescope? I'd take a looksee before I tore it all apart...
May have swallowed something, or busted a rock hard piece of carbon loose.
If you're thinking your pee-stone came up enough to ding a plug, you've likely got bigger issues..

No borescope. I replaced the plugs and it no longer has the miss so the plug was definitely the problem. I'm going to go for a drive today and see how it does. The engine wasn't disassembled completely. Just down to major components so that some leaky gaskets could be replaced. The only "change" was the heads being trued. I only ran it for a minute last nite and it ran and sounded fine. I'll just not get heavy on the throttle until I can get new, thicker head gaskets.

 

[bob64]

It did it once odds are it will happen again if you haven't adjusted anything!! You may have got lucky the first time, might not be so lucky the second!

My thoughts, if you can't get a hold of a borescope, pull it apart an check it and put thicker head gaskets on, only take a few hours verses $$$$.

Just my thoughts!!!

 

[Clarmo]

I'll just not get heavy on the throttle until I can get new, thicker head gaskets.

Plugs are cheaper than head gaskets.

 

[pontiacgp]

To me that plug doesn't look like ever fired, are you sure that plug wasn't ike that when you installed it?. I have seen plugs that got hit by a piston and there doesn't seem to be any contact marks on the plug you pulled. The loss of power and a miss can be caused by a lean mixture.