A little help here?
07-27-2003, 10:50 PM
#1
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Join Date: Jul 2003
Posts: 6
A little help here?
Alrighty. I'm no car genious, but I pretty much gotta try and figure out what the hell is going on with my z myself, otherwise my friends stepfather isn't gonna gimme a hand with it. I know.. weak, but since he doesn't charge me to do the work/show me how to do the work.. I might as well.. right?
Okay.. simptoms then:
I had the tick that I am to understand Z's have. He told me it sounded like it needed a valve adjustment, and I agreed with him on that. Well.. the very day we intended on doing it and I was driving over there, the ticking turned into a louder rapping sound. He took it for a spin and said it sounded like the valves. The sound definately does originate from that area.. sounds a lot like it's coming from the number 3rd or 4th valve from the front. Unfortunately, we didn't have time to do the valve adjustment and I had to get my *** home.. on the way back the next day, she got a little hot (got stuck in traffic) and didn't want to cool off very well. I got a huge loss of power even after she seemed to cool down some, but after the rapping noise seemed to get louder, it seemed like a good bet to pull off to the side of the road. My coolant system decided to boilover.. not fun. I got a ride to my friends house, let it cool for a couple hours, came back, put fresh coolant/water in, and managed to drive it to his house. Well.. he listened again, and still insists it is the valves. We have tried adjusting them twice now.. and the sound is still persisting. You can't really hear more than the tick at idle, but when you rev her a little, the rapping comes in. Same timing as the tick would be, and was before hand. Planning on tripple-checking the valve clearances again, as when I double-checked, some of them were oddly too spaced again. We also checked compression, and it's good. Not superb, but it is keeping compression like it should. Oil level is good, and no milky oil going on.
In all, she's being loud and obnoxious, and has a huge loss of power now. At first, it was just loud, and nothing else.. not anymore. Perhaps one of you fellows has some insight.. like I said, I don't know a ton about cars. I'm still in that learning phase, so any help would be greatly appreciated.
Thanks
<edit> also, the rapping becomes more pronounced when there is any sort of strain, ie acceleration, any sort of hill, etc.. no matter how light.
Okay.. simptoms then:
I had the tick that I am to understand Z's have. He told me it sounded like it needed a valve adjustment, and I agreed with him on that. Well.. the very day we intended on doing it and I was driving over there, the ticking turned into a louder rapping sound. He took it for a spin and said it sounded like the valves. The sound definately does originate from that area.. sounds a lot like it's coming from the number 3rd or 4th valve from the front. Unfortunately, we didn't have time to do the valve adjustment and I had to get my *** home.. on the way back the next day, she got a little hot (got stuck in traffic) and didn't want to cool off very well. I got a huge loss of power even after she seemed to cool down some, but after the rapping noise seemed to get louder, it seemed like a good bet to pull off to the side of the road. My coolant system decided to boilover.. not fun. I got a ride to my friends house, let it cool for a couple hours, came back, put fresh coolant/water in, and managed to drive it to his house. Well.. he listened again, and still insists it is the valves. We have tried adjusting them twice now.. and the sound is still persisting. You can't really hear more than the tick at idle, but when you rev her a little, the rapping comes in. Same timing as the tick would be, and was before hand. Planning on tripple-checking the valve clearances again, as when I double-checked, some of them were oddly too spaced again. We also checked compression, and it's good. Not superb, but it is keeping compression like it should. Oil level is good, and no milky oil going on.
In all, she's being loud and obnoxious, and has a huge loss of power now. At first, it was just loud, and nothing else.. not anymore. Perhaps one of you fellows has some insight.. like I said, I don't know a ton about cars. I'm still in that learning phase, so any help would be greatly appreciated.
Thanks
<edit> also, the rapping becomes more pronounced when there is any sort of strain, ie acceleration, any sort of hill, etc.. no matter how light.
07-27-2003, 11:41 PM
#2
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Sounds bad very bad...it could be many things...
Try to short out the spark plug lead you think is the one making the sound..As that will idicate if its a big end bearing which it sounds like too me.
It could also be valve bounce or detonation..more likely detonation or a big end bearing if you hear a loud metallic sound back off the accelarator it will destroy your engine as it is PINGING (pre igntion) firing before the spark cauzed by either advanced timing or low octane fuel try higer octane fuel eg 98 see how that goes.
AS for overheating well have you checked your raidator ? no losse of fluids ? thermostat may not be opening either.. or the raidator may be blocked up.
<edit> try retarding the distrubitor and use higher octane fuel if that doesnt stop this sound its defientally a big end bearing going or gone </edit>
Try to short out the spark plug lead you think is the one making the sound..As that will idicate if its a big end bearing which it sounds like too me.
It could also be valve bounce or detonation..more likely detonation or a big end bearing if you hear a loud metallic sound back off the accelarator it will destroy your engine as it is PINGING (pre igntion) firing before the spark cauzed by either advanced timing or low octane fuel try higer octane fuel eg 98 see how that goes.
AS for overheating well have you checked your raidator ? no losse of fluids ? thermostat may not be opening either.. or the raidator may be blocked up.
<edit> try retarding the distrubitor and use higher octane fuel if that doesnt stop this sound its defientally a big end bearing going or gone </edit>
Last edited by 280zx Fever; 07-27-2003 at 11:43 PM.
07-27-2003, 11:46 PM
#3
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Join Date: Jul 2003
Posts: 6
As far as overheating: Need a bigger radiator and have very limited funds. That's not a huge issue, it stays cool except in heavy stop-and-go traffic.
I currently have the car off the road, not intending on putting it back on until I have this mess sorted out.
Could you go into more detail on the "big end bearing?"
Since the sound got loud, that is what it has reminded me of.. the sound of a bearing wrapped in cloth hitting metal. A very rolling sound, not a sharp sound.
And as I mentioned, all the noise is up in the valvetrain.. I've been thinking about perhaps getting a new head and rebuilding it and putting it in. Would probably help the situation, no?
I currently have the car off the road, not intending on putting it back on until I have this mess sorted out.
Could you go into more detail on the "big end bearing?"
Since the sound got loud, that is what it has reminded me of.. the sound of a bearing wrapped in cloth hitting metal. A very rolling sound, not a sharp sound.
And as I mentioned, all the noise is up in the valvetrain.. I've been thinking about perhaps getting a new head and rebuilding it and putting it in. Would probably help the situation, no?
07-27-2003, 11:48 PM
#4
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Join Date: Jul 2003
Posts: 6
Actually, things seem to have gotten worse when I retarded the distributor. I checked the timing and noted it was way up at like.. 18 btdc. I put it back down to 10 btdc and it wasn't very happy with me.. I've also been using octane booster and 93 octane.. so I'm curious on just how vicious this is.
07-27-2003, 11:52 PM
#5
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big end bearings wear over time. it could be a slightly worn big end and causing a bit of piston slap 
Short out the spark plug lead on the cylinder you think is causing the sound when running if the sound chops out then its that cylinder causing the sound
But by the sounds of things its a big end bearing they give a lower sort of clap sound mainbearings give a even lower sound aswell.
Short out the spark plug lead on the cylinder you think is causing the sound when running if the sound chops out then its that cylinder causing the sound
But by the sounds of things its a big end bearing they give a lower sort of clap sound mainbearings give a even lower sound aswell.
07-29-2003, 09:37 AM
#10
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My friend's stepfather has all the tools and it started acting up real bad near his house.. so I limped the car there and there it is. Like I said, I'm not driving it until I resolve the issue.. lol I'll prolly be able to get out there in the next couple of days, but until then I'll just cross my fingers, lol
