What happened to this plug?

Callmewhitexr7

Registered User
I did a tune up on my car the other day and on my number five cylinder i found this plug. All the other plugs looked to be fine. What caused this and how do i fix it?


Pict0014.jpg
 
Callmewhitexr7 said:
I did a tune up on my car the other day and on my number five cylinder i found this plug. All the other plugs looked to be fine. What caused this and how do i fix it?


Pict0014.jpg

Either the cylinder is running lean or it caught some antifreeze. Replace the plug and check it again frequently. Watch for signs of blown headgaskets.
 
I would say something got a little hot. Might be time for some biger injectors if your car is moded.
 
Jason Wild said:
I would say something got a little hot. Might be time for some biger injectors if your car is moded.
Well, ya that too. 274rwhp is too much for stock injectors. I hope you have at least 36's in there. :eek:
 
Thanks for the help, but I only have the stock injectors, Also its only my #5 cylinder. The car is smoking also and I can't figure that out. The motor has be rebuilt around 15000 miles ago so i dont think the head gaskets are bad, also the last time i changed the plugs the same one looked like that, but not as bad. Could this be a sticking injector or something. Could burning oil do that? or could it be a problem in the coil? The plug only has around 600 miles on it if not a lil bit more. I've ran injector cleaner though it also. I've used the stp and i also tried some b12. I never run 89 or 87 in my car i alway run 91. Please help, cause i dont wanna mess up my motor.


NICK
 
First thing is to do a cylinder balance test to find out if the cylinder is weak already. You could pull the injector and observe the spray pattern to see if it is clogged. But seriously, you are out of injectors! You need to upgrade to at lease 36's but preferably 38's or 42's. It is generally held that 260rwhp is the limit for stock injectors. 36's will get you to 300rwhp, 38's to about 340rwhp and 42's to about 380rwhp.

If you are burning oil it could be that the rings are gummed up from misfiring so fixing the problem will cure the oil problem. However, if enough detonation has occurred repeatedly to cause the plug to burn off, then the rings may be damaged.

The plug also looks like antifreeze may have hit it. Antifreeze can literally explode a plug tip. You could have the oil and antifreeze tested for traces of mixing. That is the only sure way to tell. Pressurizing the cylinder with compressed air and watching for air in the rad sometimes works too.
 
Is that horsepower figure calculated or measured on a dyno? My SC dynoed around 270 hp and it ran a 13.69. Hard to imagine it would be almost 7 tenths faster with the same power level. But maybe it's related to different types of dyno or transmission.

Is the smoke blueish/black, or is it white and sweet smelling? White smoke would indicate that antifreeze is getting in the cylinders somehow (either from the head gaskets or the intake manifold gaskets). Excess oil burning can look bluish or black.
 
Callmewhitexr7 said:
I did a tune up on my car the other day and on my number five cylinder i found this plug. All the other plugs looked to be fine. What caused this and how do i fix it?


Pict0014.jpg
I'm starting to see a trend with the #5 cylinder. With stock injectors and bolt-ons, I managed to crack the ringlands on the #5 piston. On the next engine (all of the internal goodies w/ 42lb injectors), I burnt the electrode completely off the #5 spark plug and melted the piston. Could the #5 injector be getting the least amount of fuel due to the rail design?

Regardless, you definitely need to step up to 36's.
 
Kurt K said:
I'm starting to see a trend with the #5 cylinder. With stock injectors and bolt-ons, I managed to crack the ringlands on the #5 piston. On the next engine (all of the internal goodies w/ 42lb injectors), I burnt the electrode completely off the #5 spark plug and melted the piston. Could the #5 injector be getting the least amount of fuel due to the rail design?

Regardless, you definitely need to step up to 36's.

Kurt, I had a car here that blew the tip off #5 just like that. It also blew headgaskets but the headgaskets were leaking in 3 and 6, not 5 that I could tell. This car was stock.
 
On my - um - newer -ah- applications, I am replacing the terribly restrictive crossover connection that goes under the front of the blower with a full flow 3/8" line. I feel that this assures consistant feed to both sides of the fuel rail.
 
Dave,
Is it time we start looking at makeing a new set of fuel rails for these cars. I can think of one person thats had the same problem as well as 2-4 others that will be soon as well.?


All these Idea's Just not the time need for it all.
 
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Jason Wild said:
Dave,
Is it time we start looking at makeing a new set of fuel rails for these cars. I can think of one person thats had the same problem as well as 2-4 others that will be soon as well.?


All these Idea's Just not the time need for it all.

The problem with out injectors is that they do not lie in one plane. I saw the fuel rails that ESM made for George. A lot of work and if you added up half the hours and materials neccessary for the job, no one would buy them. Best you can do is dual feed into the stockers which is kind of what I am doing.
 
What the heck is dual feed?

And my numbers 4 and 5 plugs did that last year. I hope you didn't melt a couple pistons as in my case.
 
the HP reading is from my gtech so Im not quite sure that its accurate. How do i do a cylinder balance test? I've had these plugs in since last saturday should I pull the #5 and see what it looks like so far? Thanks


NICK
 
It has to be that injector if it is only burning up that one cylinder. Check it again. If it is doing it again, take that injector out and have it check and cleaned or replace it w/ a new one. It couldn't be the horsepower issue because they would all be burning up because the entire motor is running lean. Good Luck. Investigate that cylinder, not the entire fuel system. Do a leak down test on the motor too.

Good Luck.

- Joe
 
joe debattista said:
It has to be that injector if it is only burning up that one cylinder. Check it again. If it is doing it again, take that injector out and have it check and cleaned or replace it w/ a new one. It couldn't be the horsepower issue because they would all be burning up because the entire motor is running lean. Good Luck. Investigate that cylinder, not the entire fuel system. Do a leak down test on the motor too.

Good Luck.

- Joe
I disagree that the injector can be the only problem. Sure it could be a single injector, but I find it strange that (at least for me) 2 different engines, with 2 different sets of injectors had the same problem with #5 cylinder. On the stock engine, I just wrote it off because I needed an excuse to build my new engine. On the new engine, I was using brand new 42 lb injectors. I not only burnt the electrode off the plug, but I melted the piston. I sent the injectors out to have them tested; the all flowed within 2% of each other. The only constant between the 2 engines was the wiring harness and the fuel rail.

FWIW, when I first found the plug on engine 2, I did a compression and leakdown tests. I don't remember the exact numbers, but the leakdown was consistant throughout the cylinders and the compression tests were close to the same, except #5 was around 20 psi less. I later discovered that I had melted a "reverse dome" into the piston. :eek:

I never really did determine the cause of my problem. I'm just running a more conservative tune.
 
Whatever it may be, that cylinder is running lean for sure. That is the only way you are going to get the heat build up to melt an electrode off of a spark plug.

SC motors just may have a problem w/ the number five. The same way SBC have a problem w/ the #2 Cylinder and the same way supra's have a problem w/ #6. Throw more fuel at it and the problem will most likely go away. I have no idea how to do this really on an SC, but you may have to back off more timing per pound of boost or timing period. Check that out.
 
The reason I said it is a single cylinder problem is because I had a similar problem on a SBC in my Nova. Only it decided to eat the piston as well (on a 300 shot) That is because NX designed the plate to be used on an Ford style V8 intake as opposed to Chevy and it didn't feed adequately to the #2 cylinder, since that is the front. I would definitly look at the tune first before isolating it though I thought it had been determined his tune was okay. I suppose I missed that. Give it more fuel is the moral of the story, but don't go over kill. Safe but not Slow. :D
 
what kind of plugs are you using?
did I miss that stated
I used bosch platinums during a plug change once and decided to check them at about 6k miles while doing some other work--most the plugs were burnt down nearly that bad

ever since I always used the motorcraft DP and have no probs.
this likely isnt your problem but just thought I would mentio it
 
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