Things that make you go boom...
12-18-2002, 05:54 AM
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Things that make you go boom...
Well I don't have any information yet as to the actual diagnosis with the car but on Monday evening I stopped at the gas station across the street from my house to get a quicky car wash to remove all the dirt on my car and as I pulled into the station I heard this horrifying noise coming from the engine bay. I went straight home (approx 1/4 mi) and turned off the car after making a quick mpeg of the noise to play for my mechanic. I didn't want to drive the car if it was something progressive that would make things worse. The sound was, as far as I could tell, coming from the valvetrain portion of the engine. I proceeded to pull the plugs to check them and they were fine. I then removed the valve cover and manually cranked the engine to check for any possible loose valves or clearance issues. Nothing. At that point, I used a pen light to look down into the cylenders when at TDC. On cylenders 2, 3 & 4 I saw nothing out of the ordinary (keep in mind that you can only see an area the size of a dime) but when I looked at cylender 1 I was able to see a slight buildup of what looked to be oil / sludge. Not sure if it has any significance (spelling?) though. At this point the car is sitting on a lift after the HORROR of putting it up on a UHaul trailer and getting it off and the transmission is coming out as I write this. We had to do that anyways to change the clutch so I'm not overly concerned. We're going to be using a scope to look around inside the cylenders today and hopefully see absolutely nothing! But my fingers are certainly crossed. Even with the stethoscope the problem was certainly seeming to come from the valvetrain. I'll post pictures and updates as things progress. For now, take a listen to this sound clip and any "educated" input would be greatly appreciated. Hint hint... UL, RT 
More to come...
http://www.kpj.com/S2000/Recording3.wav
More to come...http://www.kpj.com/S2000/Recording3.wav
12-18-2002, 07:25 AM
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Cut that out! Of course I value your input. As a matter of fact I'm using some of your techniques to try to diagnose the problem. I'm just trying to find out if there is anything else that other people have experienced that may lead me to something I haven't thought of. 
12-18-2002, 07:38 AM
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stethoscope? I dont go to that extent, I usually just use a broom handle or other wooden stick and put one end to portions of the valve cover and the other end to my ear. the vavles are definately clicking away. so what's the oil level and condition look like? no check engine light at all? and most importantly - the exhaust note - is it consistent/normal or is it consistent with the fluttering valvetrain?
12-18-2002, 07:48 AM
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Broom handle or a wooden stick?!?!? This is a high tech operation here... 
j/k seriously though. The oil level was low but within limits. Condition was moderate. It's time for an oil / filter change. No CEL. The exhaust note is normal. 
j/k seriously though. The oil level was low but within limits. Condition was moderate. It's time for an oil / filter change. No CEL. The exhaust note is normal.
12-18-2002, 08:30 AM
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yea, the broom handle works quite well.
Reason I asked about the exhaust note - well, I've witnessed bent valves before first hand (not my car) and each time, there was a rumbling exhaust note. So, if that's correct then it not to say that's the case, but its very doubtful. So I wanted to rule out that possibility. Never know when something breaks or bends.
Reason I asked about the exhaust note - well, I've witnessed bent valves before first hand (not my car) and each time, there was a rumbling exhaust note. So, if that's correct then it not to say that's the case, but its very doubtful. So I wanted to rule out that possibility. Never know when something breaks or bends.
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12-18-2002, 08:35 AM
#9
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Disclaimer - I am not good at diagnosing problems using a WAV file, especially on my laptop speakers.
That said, my first thought is a spun rod bearing causing rod knock. That's a particularly loud knocking noise and usually valve noise doesn't get that bad (doesn't mean it can't happen though). Additionally, rod knock tends to be less audible when the engine is accelerating or decelerating. I notice when you rev the engine the noise diminishes greatly. Again, this makes me think rod knock.
I certainly hope this is not the case with your engine, as it will probably mean a whole new bottom end (a spun rod bearing often means the crank is f***ed). Best of luck and keep us posted.
UL
That said, my first thought is a spun rod bearing causing rod knock. That's a particularly loud knocking noise and usually valve noise doesn't get that bad (doesn't mean it can't happen though). Additionally, rod knock tends to be less audible when the engine is accelerating or decelerating. I notice when you rev the engine the noise diminishes greatly. Again, this makes me think rod knock.
I certainly hope this is not the case with your engine, as it will probably mean a whole new bottom end (a spun rod bearing often means the crank is f***ed). Best of luck and keep us posted.
UL
