knocking sounds and bent spark plug tip

[smithers584]

ok just like the title says. my buddys s14sr, has had it running for about a week, no problems, idles great and ran great, went to change injectors back to stock today and put everything together and all the sudden its knocking loud at idle. i pulled all the plugs and #4 looked like it had been hit by something and the prong was smashed down and it had no gap. what would cause this, is there anyway that a rod bearing went and allowed the piston to slap the spark plug? we also pulled the valve cover and everything looked fine under there. any suggestions? this went from a smooth perfectly quite running car to this in about 15 seconds.

[projectRDM]

Bingo.

Piston + plug = rebuild.

[smithers584]

wow, i didnt think that there was that much play in the bearings. it also went from nice and quite to knocking seriously in about 15 seconds, doesnt that sounds weird if it was rod knock?

[smithers584]

ok well we changed the plug and ran it and pulled the plug and the gap was still good. the weird thing is that the noise comes and goes, it sounds like rod knock but then it goes away for a while and comes back, and the intensity of the noise changes also. and now there is a ringing noise coming from the turbo, WTF? its just so random and happened so quick we are trying to think outside the box a little, that or we dont want to come to terms with the fact that we have to rebuild the motor. my buddy that put the plugs in the first time said that they came with the motor and he didnt even check the gapping.

[JMixedDS13M]

that's wierd for something like that to happen just from changing the injectors. are the injectors that you changed the same length?

[NIK90s13]

Hey smithers, haven't heard from you in a while,I would check in the cylinder for some odd piece of somthing, like from the injectors or somthing like that. If his valves ''swallowed'' somthing it can get lodged on the piston head or bang arround in the chamber ect. So check in the chanber before you call it a rebuild.

[R34SKYLINE]

You think maybe when you changed the injector you droped something down in the combustion chamber threw the intake manifold???

[R34SKYLINE]

that's wierd for something like that to happen just from changing the injectors. are the injectors that you changed the same length?

Thats retarded the injectors don't pretrude into the combustion chamber...lol

[Pank]

that's wierd for something like that to happen just from changing the injectors. are the injectors that you changed the same length?


what?


msglength

[smithers584]

yeah i have been so busy with a few sr swaps in the past couple weeks i havent had too much time to get on here, plus i am getting pretty proficient with sr's after having mine for two years.

i wasnt there when they swapped them, but on the s14 sr the intake plenum sits on top, so we have been taking it off to get to the injectors, which leaves the runners vulnerable to items falling in. we stuck a magnet down the spark plug hole to see if we could reach anything but with no luck. i just find it hard to believe that a piston could reach the spark plug to bend it, even with shot bearings. and i cant comprehend that it was running so good last night and idleing so great and all the sudden this. if there is something in there, whats a good way to get it out? we pulled the plug and cranked the car to see if it would spit it out, with no luck, any other ideas?

[R34SKYLINE]

yeah i have been so busy with a few sr swaps in the past couple weeks i havent had too much time to get on here, plus i am getting pretty proficient with sr's after having mine for two years.

i wasnt there when they swapped them, but on the s14 sr the intake plenum sits on top, so we have been taking it off to get to the injectors, which leaves the runners vulnerable to items falling in. we stuck a magnet down the spark plug hole to see if we could reach anything but with no luck. i just find it hard to believe that a piston could reach the spark plug to bend it, even with shot bearings. and i cant comprehend that it was running so good last night and idleing so great and all the sudden this. if there is something in there, whats a good way to get it out? we pulled the plug and cranked the car to see if it would spit it out, with no luck, any other ideas?

Your piston wouldn't not hit the spark plug unless it were the wrong type of plug (to long) or you had catastropic failure the bearing being worn would have to have been basically missing for it to maybe even touch the plug but even then fat chance, the item could have been plastic to, maybe one of those hard plastic washers for the fuel railer feel in....

[spdfreek0o]

It sounds like detonation. Maybe the #4 injector is going bad or not flowing properly.

[smithers584]

ok well i stole an aircraft borescope from work today and took it over, its one of those pencil thin cameras with a light on the end and you move it with a joystick and watch the handheld lcd, it rocks, like 6mm radius. anyways, stuck it down through the spark plug and i could see the piston definately was hit by something, no bad, but noticeably scared. the valves and everything look good from the inside and outside, we did find ball bearings in his turbo manifold, not so good, and nothing in the intake plenum. we are also using ngk 7 copper plugs. cant seem to find the culprit, we are going to drain the oil and check the plug for signs of a shot bearing. any other ideas are welcome, thanks for the input guys.

[RPS1392]

Go rent a bore scope and take a look, sounds like if the turbo is now making noise, the object moving from the chamber to the turbo via the exhast is a possibility.

[RPS1392]

lol, as I was writing that you posted....

[NIK90s13]

Man I need one of those scopes!!! LOL I sounds really cool!!!! If there is nothing in the chamber and you are sure the injector and plug is good, maybe whatever was hitting blew out. Try running it again and see if you get the knock. Let me know.

[smithers584]

yeah that borescope is amazing, lets you look inside without pulling the head. so my friend took off the turbo and mani and said the turbo is shot. we did put the other injectors back in and still making that sound, im not convienced that its rod knock, but it sounds like it. could the starter make this noise is the solenoid was going bad? like it hitting the flywheel? ive never heard one go out, but that is where the sound is coming from it seems like. also, checked oil, very very clean, no signs of anything as far as metal shavings go. we will take a look at the starter tomorrow, this is got me really confused. what would it sound like if he spun a bearing? i dont imagine he did because we ran 15w50 in it and didnt not rev very high because we are still working out bugs and tuning.

[NIK90s13]

A spun bering would seeze(sp) up or rattel BIG time.It wouldn't go away, once a bering goes, that's it, it's gone. Let me know how the starter comes out, I'm at a bit of a loss without hearing it, If I think of anything else I'll let you know.

[smithers584]

starter was fine, that was just a long shot guess. noise is still there, closer evaluation makes us think its coming from under the valve cover, but we cant find anything underthere thats loose. it sounds like a midget with a bat is running around in the motor banging on things, its so inconsistent. tell me this, he is running a chipped s14sr ecu, we dont know what its chipped for it just came like that, with 550cc's that came with it but the stock fpr. could this cause detonation, maybe stock fuel pressure not high enough for 550 and chipped ecu?

[NIK90s13]

I don't know if it would cause the knocking, but with the bigger injuctors you need the ecu chipped and tuned to the injecters and the mods on the car, or it wont run right.With the ecu you have, who knows what it for. The car will run, it will probably be mega rich.

On another note, he has hydrolic lifters, right? I have A KA, so I am not sure on the SR, if the lifters are faling it will knock or tap pretty good, and if it charges up it will go away.

[smithers584]

well we are going to pull the head today and check the valves again, and if those are good we are going to pull the motor and check the rod bearings and see what we find. ill post when i find out whats wrong. thanks for the help.

[smithers584]

pulled the head and found two little pieces of metal in the cylinder. they werent big enough to make the sounds we heard, at least thats what we think, probably like a really small sowing needle, but about 1/4 inch long a piece. we also found some damage around where the valves seat and think the valves are bent, havent pulled them yet. going to replace the valves and get a head job. still need to inspect more of the motor though.

[S14DriftstaiN]

dont forget to check your timming marks.

[NIK90s13]

Yea I was think of the valves some, the odd part is that in goes away, check the valve guids to see if they are loose.

[juanishio]

did replacing the valves fix the problems,cus i had the same problem with the bent sparkplug...i took off the valve cover turns out i had a broken rocker arm. so what hit the sparkplug??could a broken rocker arm cause this

[monopolizedinc]

Here we are several Yeats later... Having similar issues on a friends bt sr driving fine one day and started to rattel a bit. Parked it and started looking around found the same #4 spark plug bent have not found a borescope to use buti did swqp the plug just for it to rattle a bit more and bend it over again.

[Bay_area831]

Having the same issue. Ever find an answer as to why

[SlpAngl]

To have a rocker arm cause the valve to hit the spark plug, you'd also most likely have to bend the shit out of your valve as well... I'm not very familiar with SR's but in my experience that sounds like a bottom end issue, not head.