Engine Noise

[Oren09]

This is going to be difficult, so I apologize in advance.
I have a noise in my engine (yes, one of those threads..)

It sounds like a knocking sound, clank, I don't know exactly.
I really only hear it over 3000RPM, but loudest over 5K. I hardly ever rev that high but did yesterday for a fast acceleration and I was like "Gaaahhh"

I took a video last night. First bit is kinda boring.. too many turns to get to speed. Last 10 seconds or so are where the noise is loudest. 4000 RPM+ in second gear.


Is this a normal sound? Or is my lower end just worn out? The head was rebuilt a few months ago. Something serious that's going to fail catastrophically soon? The engine is just over 180K and has made that sound ever since I put it in this car.

[FestYboy]

which sound? does it make the sound in neutral?

[Oren09]

It's near impossible to describe the sound.
It does not do it in neutral. Only under load.

[FestYboy]

i would be looking at the trans if it's under load, not the engine.

[JohnGunn]

It sounds like a knocking sound, clank, I don't know exactly.

I don't hear anything that resembles your description. Perhaps it would help if you could give the exact second where the sound is most evident.

I think the idea of making a recording that demonstrates a problem is great. That way you avoid the necessity of trying to find words to describe something that words can only hint at.

I'm sure you can hear the sound you're concerned about in your recording, but you know that sound from having heard the real thing. Would you say that your recording is a good representation of the noise?

To me it doesn't sound as if the engine is getting anywhere near 4,000 rpm. Normally, at that speed I get the feeling the engine is really beginning to work hard. I don't get that feeling at all from listening to your recording.

Maybe it would be worth another try at recording it. Did you have the windows open? Experiment with that. Also with the placement of the camera. On the floor in front of the passenger's seat.

Maybe your camera doesn't have sufficient fidelity to demonstrate the noise to anyone who hasn't already heard it.

[Oren09]

Thanks, John.
I had the windows down. I'll try with them up.
Also, I recorded this with my cell phone while it was docked on the windshield. I'll see if I can position the microphone so it picks up the noise better.

[Oren09]

Sorry to be so late in replying.
I forgot to record another video for this.
Did so tonight.
Went a mile or so and some stops at intersections.
Sound is most noticeable about about 1:40 when I put the phone in the passenger floor area.


Also, this is a new phone. It does 720p HD video. Not sure if the audio records at a higher bitrate as well, but the sound does sound clearer on this video than the old one.

[FestYboy]

have you happend to replace any CV axles recently?

[Oren09]

I have not.

[WmWatt]

Does the engine smoke at all? Sounds like a slapping sound - rings?
Also if you can put it up on jack stands and run it in gear and in neutral it might provide
more information.
Do you have a stethescope or length of hose to try and locate the source of the noise when doing this?

[FB71]

worn piston pin.

[Oren09]

Oh my. That doesn't sound good.
Is that worth fixing now or waiting until it fails. I have little money

I will try to locate some hose or such and listen around to pinpoint the sound.

[WmWatt]

If it's worn rings an chemical engine additive or heavy oil should help. Look for oil specially formulated for older engines. Might be a problem passing emissions test if you have them in your jurisdiction.

[Oren09]

It passed emissions back in April. Fairly well too.
A current theory is that my timing belt is off a tooth or two because I can't properly set my ignition timing. I will try to correct the belt tomorrow. Maybe the noise is related. I will update with results when belt and timing is correct.