Bad noise - help diagnosing

[99horsey]

Ok, never posted video before, hopefully this works. Sorry - ignore the phone ringing toward the end...

Car info: 2006, manual trans, DOB GT450 installed on stock motor, tuned by Lito

So today I hit the gas in 2nd and as soon as I hit 3rd gear, my car stumbled severely and started making this horrible noise. I nursed it home (everything with the engine seemed normal - fuel pressure, oil pressure, vacuum, etc.). It's just making this horrible tapping/clicking noise. The noise is 100% based on rpm and does not change a bit whether in gear, what gear, clutch in, clutch out, moving, or stationary. More rpms, faster noise, period. It's really really loud and it sounds to me like it is coming from the bell housing area. I hoped it was maybe from the alternator or something else related to FEAD. It sounds too loud for that and it sounds like it's coming from the bottom of the car.

It's hard to tell what it really sounds like from the video and also hard to tell how really loud it is - it makes my exhaust sound quiet! Is it possible it's coming from the clutch (McLeod RST, McLeod steel flywheel)? It has sometimes been making a screaching noise when I get on the gas hard and hit third, almost like the clutch plates were slipping. Maybe this time something let go? It happened instantly. All was fine, I hit 3rd, car stumbled bad and it started making this noise. The car has stumbled when hitting 3rd hard before and I've been meaning to datalog for Lito, but it doesn't do it very often. So the stumble may or may not be related to the resulting noise.

I did hold a breaker bar to various parts of the engine and my ear to try to pinpoint the noise. Couldn't find anything obvious on the top of the engine, blower, alternator, etc. It wasn't long enough to get to my ear when held on the bell housing but I thought I could feel the vibration (timed with the knocking sound) better through my hand there.

Sorry - this isn't much to go on, but I'm trying to figure out the first steps of diagnosis. It really sounds like it's coming from the clutch area, but I'm not going to pull the tranny myself and that's a lot of labor to pay for to chase something that may or may not even be there. Your help is most appreciated.

 

[nbk13nw]

Can isolate to noise to driver or passenger side?

Sent from my SM-G925V using Tapatalk

 

[99horsey]

No. It seems to be just as loud on each side. As I drove through the subdivision (hoping I could get home without something completely failing), I could hear it echoing on the curbs and houses on both sides of the car. It really is loud enough that I think anyone in ear shot would have been staring wondering what was wrong. The best I can describe the location is in the center of the car near the bottom of the engine. It seems to come out the underneath side behind the front wheels, but it's hard to tell. I even downloaded a db meter on my phone but couldn't see a noticeable increase depending on where I held it...

 

[Badd GT]

do you have stock cams or aftermarket?

 

[99horsey]

Stock cams. Everything internal is stock.

 

[Badd GT]

ok I have a DOB kit also and have had the stumble issue for awile, I have 127500 cams and a local shop did something to the by-pass valve spring to make it a "low vacuum" by-pass and it fixed the stumble. I had problems with huge backfires when tacking and yanking gears,the car would almost go into like limp mode after, but after shutting off and restarting would go away. Since the "low vacuum" by-pass these issues have stopped.

 

[99horsey]

Interesting. Even though I have stock cams, that sounds like what happens to me sometimes. Big stumble, backfire, but then mine behaves fine - I don't have to shut off or anything. Might have to look into this bypass valve mod if I can solve the fact that my car sounds like a washing machine with a roll of quarters in it at idle and all RPMs.

 

[Badd GT]

before you look into the by-pass i'd unscrew the IAT sensor and get a syringe and rubber tube and run it down into the pan under the innercooler and see if you have coolant in there

 

[99horsey]

Seems like a good thing to check after I solve this noise issue.

 

[Badd GT]

from the video sounds like valve train noise too me

 

[Wes06]

holy shit thats my noise >.>

the fuck is making it?!

mine started after sitting for roughly 2 months because of coolant leak i didnt have time to fix.

Building a new motor since I wanted to eventually anyway, just came ahead of schedule, but this is really odd....

https://www.youtube.com/watch?v=Dmb1MRcWi7I

 

[99horsey]

from the video sounds like valve train noise too me

Ugh, I hope not! When I held the breaker bar to the valve covers and my ear, it seemed fairly smooth. I don't know how else to try to pinpoint it.

holy shit thats my noise >.>

the fuck is making it?!

Is yours so loud you're not able to drive it? This is so loud I wasn't sure I could make it home but I figured f*** it, if it's already dead, I may as well not waste my time on a tow. But driveability (at grandma like acceleration and speed) seems to not be any different...

 

[99horsey]

holy shit thats my noise >.>

the fuck is making it?!

mine started after sitting for roughly 2 months because of coolant leak i didnt have time to fix.

Building a new motor since I wanted to eventually anyway, just came ahead of schedule, but this is really odd....

https://www.youtube.com/watch?v=Dmb1MRcWi7I

Ok, that sounds the same as mine!

I'm not sure if that's good or bad for either of us...

 

[Wes06]

I didnt risk driving it, only a few idle times and ran to temp hoping it would go away per DOB but it didnt.

Its loud a fuck, my car has offroad mid pipe and you can barely hear it in that video even with the ass end backed into the garage.

I would rather save the block if possible and re sell/re-use later than drive it and blow it to hell.

Mine seemed from passenger side/passenger front but honestly until I pull it i dunno. Speaking of that I need to do that next week

Its something in the motor 100% just not sure, first trouble shooting I did was remove the belt to rule out the SC and all other belt driven bits

 

[99horsey]

Loud as fuck is how I would describe my noise. And it's definitely the same noise based on the video. Crap. My problem is I've thought about going forged and building more power, but didn't really want to drop that much money in this car.

$ new rotating assembly
$ replace/rebuild heads
$ TR6060 swap

Ugh. I'd rather put that money into something else, but I can't get squat out of something that sounds like this... Need to figure out what the hell it is.

 

[Wes06]

Like i said i honestly dunno, Ive been meaning to pull the motor by now but havent since my new block isnt done for a few more weeks.

Luckily I dont plan on selling it, I bought a block/heads/crank from guy here, replacing rods/pistons and getting it thrown together

 

[99horsey]

Have you posted about this noise here and not found any likely culprits? If so, that makes me think we're not likely to find a solution other than rebuild. Which paints me into a corner... As my car sits, I could really only sell it as a roller, which means it's hardly worth anything. Which means build it or lose my ass...

 

[Wes06]

Checkout my started thread about this

Its everything between the lifters needing to be primed and just drive it, to chain tensioner not tight enough, exhaust leaking, sc rotors, but removing belt discounted that.

One guy said record the noise and play it back through a music editor to count the taps/spikes in the audio, Doing the math of spikes/second you can tell valve train vs rotating assembly.

Mine was fast enough it sounds like rotating assembly, maybe rod is starting to let go but still together.

Ill get co-workers engine lift/stand next week so I can hopefully start pulling it apart and let you know, or if you start before then you can let me know what you find

 

[99horsey]

Crap - I found your thread. The fact that I got the same horrible noise in an instant and constantly while the engine was already hot and again after it cooled down eliminated half of the suggestions you got. Definitely sounds like the same thing, but too many possibilities... This sucks.

 

[Wes06]

Like i said, I followed the music editor idea and came up with enough taps/second to be rotating assembly, so said hell with it and started buying stuff for the build.