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Blown Spark Plugs
https://slantsix.org/forum/viewtopic.php?t=31783		 Page 1 of 4
Author:  63dartdude [ Sun Oct 19, 2008 4:28 pm ]
Post subject:  Blown Spark Plugs
Recently I thought my battery died. However, it turned out to be my starter robbing too much electricity. Once I replaced it, starts were amazingly so much quicker. But after driving it for a week or so, I heard some popping in the head area. When I started replacing my spark plugs, and spark plug wires, I noticed this:

Image

The two spark plugs on the right are from cylinders 3 & 6. It looked like they blew up. And the only thing stopping that middle from entering the cylinder was that arm. However, they are not loose.

So I replaced the coil, since it had some funny marks on it. And put in the new plugs. I cranked on the engine, and it ran beautifully for a couple of minutes, and then like crap. So I pulled out the plug in number 6, and it too was blown. It doesn't look like the plug is being hit. It looks to me like it got too much juice.

So I just ordered a new Pertronix II, since that is what I have installed now. I will be replacing the module. I figured it might be sending too much juice.

Am I on the right track here? Has anyone else had their plugs blow like this?
Author:  Wizard [ Sun Oct 19, 2008 4:44 pm ]
Post subject: 
Check the piston clearance. Too much carbon too.

When 287 head before putting on the 2.2, I checked that same plugs and I was uncomfortable with how close they are to the head deck, carbed 2.2 with this head is flat top pistons with plain valve relief cut. So used regular plugs.

Cheers, Wizard
Author:  Joshie225 [ Sun Oct 19, 2008 4:49 pm ]
Post subject: 
Do you perhaps have a 170? If so the piston to spark plug clearance is much less than with a 225. I would put in some standard reach spark plugs and try again.
Author:  DusterIdiot [ Sun Oct 19, 2008 4:58 pm ]
Post subject:  Yep...
Quote:
I would put in some standard reach spark plugs and try again.
I agree with Josh, looks like you have clearance issues....

-D.idiot
Author:  63dartdude [ Sun Oct 19, 2008 5:57 pm ]
Post subject:  Blown Spark Plugs
I have had these plugs on here for over a year, without any problems. And it doesn't appear to have any hits from the piston. If so, I would expect that 90 degree arm to be smashed. I will put in regular plugs, but doubt that will be the true answer. As I have four other plugs that look used, but not blown.
Author:  63dartdude [ Sun Oct 19, 2008 6:06 pm ]
Post subject:  Blown Spark Plugs
Image

are a couple of the other plugs. No hits from pistons evidenced here.
Author:  SlantSixDan [ Sun Oct 19, 2008 6:21 pm ]
Post subject: 
Wow...that is weird! Never seen anything like this. I agree with you this doesn't really look like piston-hit damage (I'd expect the side electrode, what you are calling the "90° arm", to be more visibly battered and scarred)...but I cannot imagine what's causing this. The plugs didn't "get too much juice", it doesn't work that way.

Help me understand: Were any of the "exploded" plugs the new ones? Or were they all the old ones? That is, did you install new plugs to replace the blown ones and then another old one blew, or was it one of the new ones that blew?
Author:  norcalmoparnut [ Sun Oct 19, 2008 6:33 pm ]
Post subject: 
There's no such thing as too much voltage to the plugs. Mechanical damage is just that, mechanical. Something is either bouncing around inside your cylinder (s) or you have a piston hitting your plugs, (i've seen a rod bearing let go and let the piston come farther up to hit plugs).
I've also seen a piece of debris sucked back into the intake and blown around between cylinders. Thoes long reach plugs look like something a 4.2L jeep would run. Try some regular reach plugs. Good luck.
Author:  THOR [ Sun Oct 19, 2008 7:02 pm ]
Post subject: 
I would almost guess to say that the combustion in the cylinders was what did it. For example, if they are way black, extra fuel may have been exploding on the sides of the electrodes causing them heat up and blow over. Of course, you would think if there were any that were going to have that problem, it would have been on #3 and #4, where the A/F mix is the richest.

Hmmm...

~THOR~
Author:  HyperValiant [ Sun Oct 19, 2008 7:04 pm ]
Post subject: 
I honestly dont beleive that it is piston damage as I have been running the same plugs as 63Dartdude in my own 63 Dart with a 170 for over 2 years with many 5000 rpm blasts and never experienced any damage but my engine is completely original in as much as the head has never been removed and it retains the original comp.ratio.
After looking at the plugs again it does look like somthing has hit them but not a piston.Is your head stock or has it been shaved?The only possible thing I can think of to cause that would be as others have said is a overabundance of carbon build up.
HyperValiant
Author:  63dartdude [ Sun Oct 19, 2008 7:10 pm ]
Post subject:  Blown Spark Plugs
Yes, on the first photo, a brand new plug is there on the left.

I just think it is weird that 3 and 6 both have the same problem.

I will try to put in regular spark plugs tomorrow night, and see what happens.
Author:  440_Magnum [ Mon Oct 20, 2008 7:40 am ]
Post subject:  Re: Blown Spark Plugs
Quote:
Yes, on the first photo, a brand new plug is there on the left.

I just think it is weird that 3 and 6 both have the same problem.

I will try to put in regular spark plugs tomorrow night, and see what happens.

It sure looks to me like you've got something loose in the combustion chambers. Odd that its two at once, but stranger things have happened.

You might try cranking the engine over with the coil disconnected and plugs 3 and 6 removed to see if anything gets blasted out of the plug hole on the compression stroke. If something is loose in there, it could easily damage something a lot more critical than spark plugs.
Author:  terrylittlejohn [ Mon Oct 20, 2008 9:35 am ]
Post subject: 
it look like plugs that have seen detonation , the heat bends the ground strap and cracks the porslien at it base inside the plug. the black color is when you keep the engine running and the plug is missfiring so it looks rich with fuel build-up. check the rotor and cap and timing also wires for signs of cross fire.
Author:  emsvitil [ Mon Oct 20, 2008 2:30 pm ]
Post subject: 
Quote:
it look like plugs that have seen detonation , the heat bends the ground strap and cracks the porslien at it base inside the plug. the black color is when you keep the engine running and the plug is missfiring so it looks rich with fuel build-up. check the rotor and cap and timing also wires for signs of cross fire.
I was thinking of lean detonation, but since they were black dismissed it...........

Now that there's an explanation for the black, look for an intake air leak.
Author:  63dartdude [ Mon Oct 20, 2008 2:40 pm ]
Post subject: 
Intake leak is possible. I just installed the dutra dual manifold. For now, I will be doing a compression test, to see what it looks like. I was 150 before. I will also open up those two cylinders by taking the plug out, and turning the engine with my remote starter, and no coil. Just to see if it will shoot anything out. And I will double check everything on the Dutra work I did.
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