Spark plug electrode crushed

[66SportFury]

What plugs are you running in it? Number/Brand? I'm pretty sure they should be shorty's,.like an Autolite 85?

 

[68plymouth383]

If the parts store gave you plugs for an la 318 instead of a poly 318 that could of been your problem...... I can't imagine many parts stores stocking poly plugs.......

 

[68plymouth383]

There saying that the poly 318 use the rj12yc champion plug. That's the same plug my 440 uses. I would have thought they use a much smaller depth plug......

 

[66SportFury]

Hmmm, I would double check that rj12yc in a Poly. I'm really not familiar with the Poly, so I'm not sure. I did call my local parts house and they said the Autolite brand 85 is the plug for it and is a short reach, but hey they could be wrong. There are a few members on the site that have Poly's. Maybe they will chime in.

 

[Ripinator]

Hmmm, I would double check that rj12yc in a Poly. I'm really not familiar with the Poly, so I'm not sure. I did call my local parts house and they said the Autolite brand 85 is the plug for it and is a short reach, but hey they could be wrong. There are a few members on the site that have Poly's. Maybe they will chime in.

Aaahhh. . . The Autolite 85. Same plug I use in my '65 Panhead.

 

[has2bmopar]

There saying that the poly 318 use the rj12yc champion plug. That's the same plug my 440 uses. I would have thought they use a much smaller depth plug......

The Poly engine will use the same size/short reach plug as the B/RB engines, but the temp of the plugs will vary depending on their application.

I had a plug get smashed in my boat engine and it was from chunks of Chevy ( :sign18: ) piston that had broken off above the top ring.

 

[66SportFury]

FanFish, did you ever check to see what plugs you're running,..number brand? What is the outcome? The LA 318 takes a long reach,.so make sure the parts house gave you the right plugs. Picture of the installed plugs would help. I wouldn't run the motor until you're sure.

 

[Fishfan]

So the carb guy re-replaced all the plugs. Don't know which ones he put it but I didn't want to mess with them so I bought a spark tester and tested all 8 and they are working just fine now. I suspect the wrong plugs were in there but then why would only a couple of them crush? It's very weird.

 

[Fishfan]

I still have the ones I took out myself (one of them was crushed). I will report on which ones they were when I get home (I'm away for a few days).

 

[Big_John]

So the carb guy re-replaced all the plugs. Don't know which ones he put it but I didn't want to mess with them so I bought a spark tester and tested all 8 and they are working just fine now. I suspect the wrong plugs were in there but then why would only a couple of them crush? It's very weird.

Probably because of the way the electrode was oriented when it tightened. Six of the plugs had their electrodes in a position that the piston missed and the other two were in position that hit the piston.

 

[70bigblockdodge]

Probably because of the way the electrode was oriented when it tightened. Six of the plugs had their electrodes in a position that the piston missed and the other two were in position that hit the piston.

That is probably it because their plugs are very near top of c.c.

 

[66SportFury]

I still have the ones I took out myself (one of them was crushed). I will report on which ones they were when I get home (I'm away for a few days).

I would pull a plug that was installed by the "Carb Guy" to see what you have in there. Can you post a picture of the old plugs and new ones? You won't be messing with anything and it's a matter of pulling a plug, taking a picture and re-installing it,....just in case he installed the same plugs you had in there to begin with.

 

[livininharrow]

I dropped a plug while changing them early this year. Didn't think much about it, just picked it up and installed it. Engine idled poorly and had an obvious miss. Double checked all the wires, still not good. Pulled the plugs one by one and of course the last one I pulled was the one I dropped, the electrode was making contact with the center....another lesson learned the hard way.

how can u drop a plug and not check it before installing it. why would we bother gapping them in the first place?

 

[Fishfan]

Here's the crushed plug I referred to in the initial post. It's a Champion RJ14YC.

 

[polara71]

Ouch!

 

[Fratzog]

That looks pretty nasty. A good case for Serlock Holmes.

 

[1978 NYB]

Have you figured out what happened?

 

[Fishfan]

Nope. Gonna check the spark on all cylinders again this weekend.

 

[heyoldguy]

Earlier posters were correct. This happens when a foreign object is floating around in the engine. When you changed the carburetor something fell into the intake, bounced around from cylinder to cylinder and eventually was ejected out the exhaust. If it hasn't been spit out, you'll eventually get more bent electrodes or a destroyed engine.

 

[Fratzog]

Best theory I've heard so far.