Interesting Noise (video inside)

[aye mate]

So I was out cruising tonight and this noise started as I was making a hard right turn (sliding a little bit on a wet street). My first thought was oil starvation and subsequent rod knock as the noise was fairly loud at first. So I parked it and shut her down, dumped an extra quart of oil in (never leave home without it) and then started her up again and babied her home. During the drive home I noticed the sound was not constant, but would change volume and rhythm and fluctuated with RPM. During the entire 15 mile ride home Oil Pressure never appeared low and the temp. never moved. I pulled her in the garage and could barely hear anything at idle and took this video. Now I'm thinking not rodknock, but maybe something in the valve train.

http://smvideos.suprapics.com/index.php?fileid=5f80f94a5776614967d652a1f8adf1b9

Give it to me straight, Doctor.

Thanks, Jake

EDIT- The video is kind of big but I wanted the quality to be as good and clear as possible.

[IJ.]

AM: Sounds almost too fast to be RK have a look for an MIA Shim.

[aye mate]

Yea, thats what I'm hoping.

[IJ.]

<fingers crossed> It's an easy to find fault if it's valvetrain!

really hope it's not RK!

[supra90turbo]

:( vid no worky for me....
i was unable to download the codec apparently...

[MDCmotorsports]

Yeah the vid doesn't work...

[IJ.]

DivX version here! (http://smvideos.suprapics.com/index.php?fileid=16776ff79fcb0f6d7dabe03db54bcd68)

[johnathan1]

I would pull off the cam covers...you'll likely spot the problem right away.

[aye mate]

Ok took off the cam covers and didn't see anything out of the ordinary all lobes were in contact with their shims and I didn't see any shims out of place. I drained the oil and I am gonna get some magnets tomorrow so I can check it for metal shavings. Also I think I might check the clearances in between the cams and shims...if that would do any good.

[3p141592654]

Sounds like valve noise to me too. Check your bearing caps see if they are all torqued down okay to 14ft-lbs.

[IJ.]

AM: RK won't show up on a Magnet until you're down to the backing plate as the bearing material is nonferrous.

[aye mate]

Yea... I was thinking about whether or not the material would be magnetic. I will try the bearing cap suggestion. Thanks 3P and IJ.

[IJ.]

AM: I'd imagine if it were valve train related it would be very obvious as soon as you pulled a cover :(

[xarewhyayen]

valvetrain noise=twice the speed of crankshaft noise... that kinda sounds too rapid to be bottom end. Try going to autozone or whatever and getting a stethoscope with the long end and try to pinpoint where its loudest. Good luck with the diag and fix

[aye mate]

No chance it would be an extreme case of injector pulse now would it?











Sorry, I'm scrambling....like an egg.

[IJ.]

Xare: It's actually half speed but higher frequency so sounds faster ;)

AM: :( grab a long screw driver run the motor and place the handle on the bone just in front of your ear then put the other end on the block this might help you locate the source of the noise.
(Works with a broom handle as well)

[xarewhyayen]

IJ... higher frequency is what i meant by it... thanks for clarifying :)

[aye mate]

I'm gonna throw some 15w50 Mobil1 in tomorrow to see if that quiets it down. I had 7 quarts of 10w30 M1 in it when this started and its been in the 90's here.

[aye mate]

Little update. I was driving the car and the noise had quieted down considerably after about a week. Remember I said by the time I got it home the first night it was quieter than when it first started. So a week later I drove it to work to let our mechanic listen to it and it was very quiet while driving and barely audible when revving in neutral. So later that day the noise totally went away and I have driven it several times since with no noise and no loss in oil pressure or performance. I guess it was just a stuck valve caused by some oil build-up?

[hottscennessey]

I think I had the exact same problem.. came and went all in a day. I havn't heard it since. Its literally heart-stopping. I'm glad yours didn't turn out to be RK either!

[935motorsports]

Sounds like valve to me.

Listen to it under the car, it is usually easy to tell where noise is coming from. Feel the motor while it revs, use a screwdriver to listen, there are lots of tricks.

You can also pull the valve covers and check valve clearance. It takes an afternoon to do, but it is worth it to know what is going on with your motor.

Any work done recently?

[aye mate]

Nope, last time I did any work that would have messed with internals was when I replaced my NON-BHG two years ago. Never had a problem since.

I was thinking about doing an engine flush with that Bars Leak or BG stuff. Any idea how that stuff would work?

[aye mate]

The noise came back and it is constant. I'm taking the cams out tomorrow to check out everything there. But I'm really thinking that its RodKnock.