My Hemi Is Pinching Plugs Closed...Help Needed!

You'd need a LOT of carbon built up on the piston dome to close a plug's electrode.
There's something in there floating around.

If it hasn't been noticeably hammering while you're driving, you can be optimistic that the piston isn't trashed.

This is exactly why I like spending the extra money on forged pistons for a vintage engine.

-Brad

 

Is it possible that the valve timing is now off (chain skipped) and that a valve head has hit the top of the piston and is bent enough to hit the spark plug? Just a wild thought.

 

Thats good to know,cause when i pulled a plug from my 241 it had a gasket (metal ring) on top of the plug tube.Thanks for the info.Still it might help him ,haha.......................YG

 

Blah, blah, blah. Pull the head, something is fucked.....

 

That's the bottom line, if I was close to the OP, I'd go over and do it for him! We want to KNOW!

Bob

 

I'm interested to know the issue here, I'll follow this.
73RR & TRwaters would be two people that would give great advice on this issue.
Slim

 

I might be able to borrow a bore-scope from work if you didnt want to pull the head.. And I can definetly let you use my timing light.

 

So? Head off yet?

 

Is it? If yes, then tell us what was found, if no, then take the head off and inspect.

 

If a valve was bent that much, there would likely be some interesting valvetrain clatter to go along with it.

 

It is very easy to see in the cylinder with the $2 Harbour Freight light I mentioned earlier. I would have a look inside for no more money than that. You shoud be able to see any damage on the piston top.

 

Did a compression test yesterday. Zero compression out of the culprit hole. Im heading out to the shop right now to pull the head. I did a flashlight inspection, and the top of the piston that I can see looks the same as all the others. No obvious gouge marks. I can definitely hear some strange valve clattery noise when I crank it. All the other holes had good, consistent compression. Anyway, ill post some pics and news later tonight. Thanks for all the response guys. And it is cylinder number 3 on the driver side, not 4 as I posted before.

 

If you pressurize the bad cylinder you will hear the air coming out of the crank case it is bad rings, if the air comes out of the carb it is bad intake valve and from the exhaust means bad exhaust valve.

 

Been there broke that^^^^^^^^^ didn't hurt it too bad, spit it out and never any more problems.

 

Is it the actual #3 cylinder (which is the second cylinder from the front on driver's side) or really #5 (which is 3rd from front on d.s.)?

 

any news?

 

So the head is off, and it was very obvious what was wrong. Clueless as to how this got inside my motor. Looks like it used to be a nut. Cylinder wall is still fine, piston got munched but is not cracked or broken. Bent a valve. Taking the head tomorrow to the machine shop.

 

It is the actual #3 cylinder, yes.

 

Wow, some us us were subscribed to the piston coming apart but the valve makes more sense now that there is evidence of a nut bouncing around in it.

I bought an Olds years back and someone dropped a carb stud down the intake (bought it les the carb with the holes unplugged on the manifold... i was 18...) and it punched a hole through the piston top.

Bob

 

Ouch! That's a bummer. What does the cylinder wall look like?

 

We had a similar problem in our dragster in the 60's. It turned out to be the exhaust valve that it had spit out of the stright pipes just before the top eliminator run.

Ps, it diden't matter, we won anyways!

 

Ouch. That is a bummer. Hope the repairs can be made quickly and inexpensively.

 

Awww man! Bummer. Well, at least the machine shop can take care of the head and valve portion with a few bucks thrown at it.

What are your thoughts on the piston? Wondering if all those craters are going to cause you some undesired stress risers around the perimeter that might lead to a failure down the road.

Anything metallic squeak by to the pan?

 

this is a lesson for everyone - keep your nuts out of the motor!!

 

You haven't been fooling around with the neighbor's wife, have you? That nut hasn't been in the engine very long. Either you or someone drooped it in the carb or open manifold.

 

In pic #1 it looks like the object is near the end of the head. Is that where it was when the head was removed? Seems weird it was there and not near the actual cylinder in question.

I would take the carb apart and make sure that it isn't coming aparton it's own.

 

And the winner is Rusty Otool he was the first one to call it right Good Job Rusty, It looks to me like I might pull the piston out of that hole to take a look see!
Hope it all goes well.

 

Just sitting there for the pic , it has a shadow ...

For what it's worth , that nut may have been jammed somewhere and only recently worked its way free .

Many nuts and places to hide ...

 

I wasn't going to say nothin'.... I'd still like to believe that it wasn't an act of vandalism. One reason I'm a bug about sealing up my open motors.

Bob

 

Damn, that sucks, any idea where it came from?

it could have been a hell of alot worse.

JEFF