Help! Loud knocking sound! Edit: Don't think its rod bearings

[jonmon6691]

I was out driving today (A little hard I might add) And I started noticing that it didn't sound right above 4k rpms. So I pulled over and I heard this noise at any engine speed over about 2500 rpms.

I just replaced rod bearings about 5000 miles ago and no lights where on the dash (Low oil/pressure for example)

http://www.youtube.com/watch?v=cCdV-fqFpVE

Does this sound familiar to anyone?

 

[elarm1]

Sounds like a valve to me

 

[SuperHO]

sadly, it does sound familiar...although, take a look at your crank pulley and see if it's wobbling at all. otherwise, I say yank the pan and survey the damage.

 

[Eric VerValin]

injector?

 

[Kens1992mtxSHO]

No one will ever know until you start to tear it apart. IMO, I would start from the bottom up.

 

[Racer X]

Crank pulley/ crank cancer. If it's knocking around, it's already lost it's interference fit on the crank snout.

Sorry man.

 

[jonmon6691]

I just replaced the timing sprocket and key and used green loctite a few weeks ago because of crank cancer!? I made sure the crank bolt was around 145'#. Could not doing valve lash adjustment/ replacing old shims cause anything like this? Its possible that its never been done before.

 

[Kens1992mtxSHO]

It's possible you spit a shim but not likely. Couldn't hurt to check, but it's doubtful. Get yourself a 3.2, swap it in and call it a day.

 

[SuperHO]

curious question...when you did the bearings, did you torque them properly?

 

[frosho]

And did you use some type of **** on the bearings?

 

[SeanMc]

I had this problem once. After checking my wires, and spark plugs, it ended up being my coil pack.

 

[Racer X]

I just replaced the timing sprocket and key and used green loctite a few weeks ago because of crank cancer!? I made sure the crank bolt was around 145'#. Could not doing valve lash adjustment/ replacing old shims cause anything like this? Its possible that its never been done before.

Wait, so you're saying that you did a repair for crank cancer already?

If you're saying that you had crank cancer, and didn't replace the timing gear and crank pulley, of course you're going to be back in the same boat sooner rather than later. The axial faces of the pulleys wear also in a failure scenario, so much so that you could torque that crank bolt to 200# and still have them work loose. Trust me, I've been there.

[YOUTUBE]KG6Ju10CUx4[/YOUTUBE]

 

[1995mtxsho]

Sounds like a bent/sticking valve to me.

 

[SuperHO]

sounds like the squashed rod bearing i had...

 

[jonmon6691]

Yes I torqued correctly, dual stage style.
I used motor oil to **** them, but I replaced 'em 5k miles ago.

Yes I REPLACED the key and sprocket, damper pulley was undamaged.

How can I make sure it is or isn't the coil pack?

 

[whiteguy3]

Sounds Like a stuck valve. Try seafoam and injector cleaner. Sometimes that helps. They can get gummed up. Do you use 89 octane?

 

[jmpSHO]

Sounds like the rod bearings to me. How did the crank look when you replaced the bearings?

 

[jonmon6691]

I use premium (I think its 89, always cheveron if that helps, idk)

The crank felt fine, plastiguaged the worst looking one and it was fine.

 

[Eric VerValin]

Now after hearing your second video man......


its a rod bearing... mine did that 'fade in and out' kinda crap... you didn't have it revved up in the other video.. and after hearing that, I would definately pull the pan and see if you see anything special before it gets really noisy and you need to get another crank.


I would just get some more RTV, and some plastiguage.... if your lucky, it will only cost you $10, and you'll know for sure how much you need to worry about this noise. Wish it was a simpler solution, but I'd reallllllly want to look at the lower half of your motor after hearing that.

When you plastiguage it too... be picky about it... if you remember the 'worst' one.. do it a few times... top and bottom.. and make sure you get it all out of there too before startup.

Good luck man! I'm rootin for ya... I'd even offer to help if I wasn't on the other side of the country..

 

[mooseSHO46]

sticky valve it sounds to me