Rod Knock, Spun Bearing, Something?

[TSIMonsteR]

first and foremost, I read several threads pertaining to the subject and have several starting points for diagnosis based on what I've read. I don't have some of the tools I need at the new house, and instead of twiddling my thumbs waiting on a friend to bring what I need, I thought I'd post up a thread to help myself and anyone else with similar issues in the future. Thanks in advance.

So, the cars been running great. I've put over 3k on it since the beginning of February (mostly hwy miles). Monday night, on the way home, it ran fine, but I heard something unusual. I pulled into Little Caesar's and popped the hood.

Both the turbine housing and exhaust manifold were glowing. (just got off the hwy going 80 for about 30 miles, so this maybe normal, not sure, but I've never notice it before... but I guess I've never looked.)
**(EDIT- My research tells me that it is, in-fact, normal to an extent.)
The car was idling fine. I checked the gauges and link. Coolant temp was at 196, and everything else was fine. No CEL. According to the stock gauge, there was oil pressure.

I revved it up a bit and heard a knocking sound that I haven't heard before. Can't hear it at idle, but rev just a little and it sounds like somethings rattling around in there.
My dad was close by helping me get my new bed to my new house, so I called him and we hooked up a strap and towed it home (not far).

I thought maybe the oil cooler backed off and it was low on oil or something. I checked the oil, it was perfect. It looked clean, not burnt or anything, and there was plenty. I examined it very carefully and seen no metal shavings of any kind. (I plan to cut the oil filter today at some point to be sure)

I took the top timing cover off and rotated the crank a bit, the cam gears, at least, lined up.

What do you guys think thus far? I really can't pinpoint the sound, and I hat to run it again to try. I figured if it was a spun bearing, there would be some indication to low oil pressure, or low/old oil. This is Mobil 1 10w30 thats barely 3000 miles old and is checked at every gas tank fill up.

I was hoping maybe a lifter seized or something and that was causing the noise. I'm thinking maybe it got out of time somehow and started running lean? Time for Compression Test, I suppose.

I REALLY hope its not rod knock or a spun bearing.

I'll post updates as I start tearing into it

 

[BogusSVO]

rod knock/spun bearing... same thing

the 4g dose like the balance shafts to let loose and can sound like rod knock.

how many miles? how ofen and hard have you hammered on it?

 

[TSIMonsteR]

rod knock/spun bearing... same thing

the 4g dose like the balance shafts to let loose and can sound like rod knock.

how many miles? how ofen and hard have you hammered on it?

Been 3 to 4k since the I did a T-Belt/HG job. Checking timing right now.

I cranked it once more and I can almost swear its coming from the head area. I popped the valve cover and I don't see anything unusual. Plenty of clean oil coating everything.

I rotated the crank a bit by hand and it seemed fine as well. Didn't hang at any point (besides the normal pressure from the valve springs).

As I rotated, however, I heard some weird hissing, like air was seeping through. This points towards the valves being bent, but wouldn't the crank be hard to turn by hand?

I am pulling the accessory belts now to check the timing, but there is no abnormal slack in the timing belt, and the belt itself looks healthy. :-|

 

[BogusSVO]

it depends on where you hear the hiss, out the TB or tail pipe, not the best, but if it was thu the head/VC thats just compressed air thu the rings (blow by) some is normal

a spun rod bearing will not hang up on the crank for the most part, the crank is beat smaller and the rod bigger.....

you may want to drop the oil pan and grab the balance shafts and try to wiggle them

 

[TSIMonsteR]

Yeah, the hiss was coming from the valve area (I had the VC removed). It was only slight, so blow by sounds reasonable.

I'll drop the pan soon enough. Thanks for the help, I really do appreciate it. I only hope to return the favor as I become more knowledgeable about these things.

Lastly, should I try this, or go ahead and drop the pan to be safe? ( again, at idle, I can't hear the knock. I have to be at at least 2k rpms or so)

Easy test for rod knock is to remove the spark plug wire on each cylinder 1 by 1. This will take the combustion load off the bearing and the noise will go away if it indeed is a rod knock.

 

[BogusSVO]

drop the pan.. that way you can check it for metal fake, and also check the balance shaft bearings

wiggle the rods while your there, and look for one rod to be discolored and just in general look around for anything odd.

 

[TSIMonsteR]

drop the pan.. that way you can check it for metal fake, and also check the balance shaft bearings

wiggle the rods while your there, and look for one rod to be discolored and just in general look around for anything odd.

Will do. I'd rather put forth the effort to be positive.

Any tips on dropping the pan? From what I understand... drop the downpipe, xfer case, drop the cross member, unbolt the drivers side axle, and then it should come down, right?

I'm leaning more and more towards a spun bearing. After listening to a ton of youtube vids. It sounds just like rod knock. Maybe its just not bad enough when idling to make a lot of noise?

I'm wondering if I should just go ahead and pull the motor.

 

[TSIMonsteR]

By the way, number 1 bearing spun hard and scored the crank. Number 3 was worn and ready to spin as well.