This is topic engine knocking when at a stop.??? in forum Tech Talk at Northern California Ford Owners .
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Posted by BLOWN 4.6 (Member # 4789) on
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i have a 96 mustang 4.6 supercharged.it started making a knocking sound when at a stop,it wasnt making this sound before.i changed the spark plugs,i went from motor craft to ngk v-power and i gapped them at .40. could that be the problem?? other than that knocking sound the car runs fine. i need help??
Posted by 94gt (Member # 3060) on
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arent those ngk's platinum? I know that you are never supposed to run platinum plugs on a s/c car.
Posted by BLOWN 4.6 (Member # 4789) on
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they are iridium copper spark plugs. could that be the problem???
Posted by 94gt (Member # 3060) on
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if the only thing you changed is the plugs, that would be your issue. check the gap on the new ones and try the motorcrafts again
Posted by Joooestang66 (Member # 2828) on
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Sounds like spark knock, spark knock isn't good.
Posted by SmokinLX (Member # 1684) on
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How much boost are you runnin? Do you have an aftermarket ignition?How long after the spark plug change did you notice the noise? Good luck
Posted by BLOWN 4.6 (Member # 4789) on
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its been 300 miles since i installed the ngk. what ive noticed is that it starts to make that knocking sound and then goes away and them comes back. what are some good spark plugs for a supercharged 4.6, think its running 8pounds of boost or so. need help.....
Posted by Fostang (Member # 3752) on
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Pull out the plugs and check em.
[ August 08, 2005, 09:47 PM: Message edited by: Fostang ]
Posted by h8louzn (Member # 1075) on
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quote:
Originally posted by Joooestang66:
Sounds like spark knock, spark knock isn't good.
Wow, I have never heard of spark knock at idle.
Don't think that would be it!!
Posted by 92stangLX (Member # 3252) on
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Check your plug wires. I had one of mine fall off and it sounded like I had a knock or valve tick.
Posted by BLOWN 4.6 (Member # 4789) on
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all wires look good,since the spark plugs im running are NGKs tr-55 and there stock heat range and i heard that isnt good.i was told to run colder spark plugs.so i went out and got some motorcraft -22c (ford lighting)spark plugs that are colder than stock and im gapping them at .34 ill see how that works out. thanks to everyone for their input. ![[patriot]](graemlins/patriot.gif)
Posted by BLOWN 4.6 (Member # 4789) on
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i took off the ngk spark plugs and 7 of them where kind of green from the hook,and 1 of them had the hook smashed and was full of oil. what could of caused that??? need help.. ![[Confused]](confused.gif)
Posted by TRIXSNK (Member # 2844) on
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quote:
Originally posted by BLOWN 4.6:
i took off the ngk spark plugs and 7 of them where kind of green from the hook,and 1 of them had the hook smashed and was full of oil. what could of caused that??? need help..
Either the electrode was damaged on install or something in the combustion chamber made contact with it.
Pics would help.
How does the oil look any particles?
Possibly bent or broken valve?
A compression test may help if the car is running rough.
Posted by BLOWN 4.6 (Member # 4789) on
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the car is running fine,the only thing is that at a stop it sometimes makes a kncking sound???
Posted by CDT (Member # 5004) on
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quote:
Originally posted by BLOWN 4.6:
i took off the ngk spark plugs and 7 of them where kind of green from the hook,and 1 of them had the hook smashed and was full of oil. what could of caused that??? need help..
broken piston, for sure.... Come on down and get a quote on an engine...
Posted by stoauto (Member # 2803) on
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yeah, time for a new motor.
Posted by TRIXSNK (Member # 2844) on
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CDT and Stoauto know what they are doing so not surprised to hear such an immediate and what seems to be a definitive answer.
Posted by BCINGUU (Member # 2397) on
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You need to watch your plug depth. Different heads have different plugs. What heads are you running, and what plugs? I sincerely hope your plugs aren't too long.
Posted by h8louzn (Member # 1075) on
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Evan don't know squat!! ![[Wink]](wink.gif)
Posted by BLOWN 4.6 (Member # 4789) on
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thats funny cause the car has been running fine ever since i changed the plugs..
Posted by Eddie510 (Member # 2354) on
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run it a day or to now and check a sparkplug again see how it looks, eddie
Posted by 92stangLX (Member # 3252) on
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quote:
Originally posted by TRIXSNK:
quote:
Originally posted by BLOWN 4.6:
i took off the ngk spark plugs and 7 of them where kind of green from the hook,and 1 of them had the hook smashed and was full of oil. what could of caused that??? need help..
Either the electrode was damaged on install or something in the combustion chamber made contact with it.
Pics would help.
How does the oil look any particles?
Possibly bent or broken valve?
A compression test may help if the car is running rough.
Do a compression test. This will tell you a lot about what is going on. Also, you said that you pulled out the NGKs and inspected them. Did you pull out the plugs you just put in and do the same?
Another thing you may want to do is get a stethescope (sp) and find out which cylinder the knock is coming from and then check that plug and see what it looks like.
Posted by BCINGUU (Member # 2397) on
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Hey bro, tell us what heads and plugs you have. Post up some pix of the plugs too if you can.
Posted by RobertTS (Member # 1022) on
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Its a fouled plug what u have there, change the plugs to what you originally had before the knocking sound, Im pretty sure youŽll be ok,,same thing happened to me a long time ago, everyone thought it was a damaged piston but it was only a fouled plug. Try it out.
Posted by stangnut (Member # 5937) on
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COULD BE A BAD BEARING ,THEN DUE TO THE ETRA CLEARENCE THE PISTON HIT YOUR PLUG, NEED TO CHECK BEARING CLEARANCE.
Posted by BLOWN 4.6 (Member # 4789) on
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the new plugs i installed are gapped at .34 is that good or bad??
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